Documents published in 2024 : Scipedia

Finite Element Formulations for Axisymmetric Solids: A New Approach Based on the Petrov-Galerkin Method
F. Zähringer, P. Betsch

ECCOMAS 2024.

Abstract
The sensitivity of conventional finite element formulations to distorted meshes is a well-known problem. In this work, it is investigated whether an 8-node Petrov-Galerkin f inite element formulation can reduce this mesh-sensitive behavior when simulating linear-elastic axisymmetric problems. The numerical investigations show that the Petrov-Galerkin formulation exhibits significantly better behavior than the Bubnov-Galerkin formulation in certain cases. However, the results also indicate that this is not generally the case.
Abstract
The sensitivity of conventional finite element formulations to distorted meshes is a well-known problem. In this work, it is investigated whether an 8-node Petrov-Galerkin [...]
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High-order Flux Reconstruction schemes for turbulent combustion
R. TAMOU, J. BOHBOT, J. COATLÉVEN, V. PERRIER, Q. Tran

ECCOMAS 2024.

Abstract
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A Multi-layered Integral Approach to the de-icing process
H. Beaugendre, A. Benoit, F. Morency, M. Parisot

ECCOMAS 2024.

Abstract
The modification of the shallow water icing model to handle de-icing phenomenon is the main focus of this study. As stated in the original model [1], the runback water is modeled utilizing a lubrication assumption for the water film velocity profile. A constant film temperature Tf(t,x) is then calculated under the thin-film hypothesis. Unlike the simplified icing model, the temperature field within the ice layer Tice(t,x,z) is no longer assumed to be constant. Instead, a temperature profile is utilized, enabling the generation of a static film on the wall when a heat conduction source term from a resistance is present [2]. A Temperature profile Ts(t,x,z) is also used in the static film layer if the model predicts the occurrence of this state. In the energy equation for both the solid ice and liquid portion of the static water film, transverse transfers are not considered, a 1D heat equation is then resolved. An integral approach and proper boundary conditions are used to close the problem. The validity of the integral method deteriorates as the thickness over which vertical integration is performed increases. To avoid this problem, a multi-layer approach is proposed. The thickness of the ice block is then divided into three layers of identical thickness. The purpose of this study is to offer a straightforward and robust method suitable for conducting industrial test cases. The model will first be introduced, followed by a description of the numerical approach. Subsequently, validation test cases will be conducted. Realistic de-icing scenarios will then be designed to evaluate the model [3]. Additionally, non uniform roughness effects will be examined.
Abstract
The modification of the shallow water icing model to handle de-icing phenomenon is the main focus of this study. As stated in the original model [1], the runback water is [...]
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Calibration of Heston Stochastic Local Volatility Model by Numerical Solution of Nonlinear Fokker-Planck Equation
S. Stoykov

ECCOMAS 2024.

Abstract
The Fokker-Planck partial differential equation is used to compute the probability density function of the Heston stochastic local volatility model. The solution of the Fokker Planck equation is required for the calibration of the leverage function, which plays an important role in the Heston stochastic local volatility model. The current study describes a numerical method for solving the nonlinear Fokker-Planck partial differential equation. The solution is demonstrated to converge to the one generated from the implied volatility surface by comparing call option prices.
Abstract
The Fokker-Planck partial differential equation is used to compute the probability density function of the Heston stochastic local volatility model. The solution of the Fokker [...]
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Immersed boundary methods for high-order discretization of the compressible Reynolds Averaged Navier-Stokes equations
D. Lodares, J. Manzanero, E. Ferrer, E. Valero

ECCOMAS 2024.

Abstract
The Immersed Boundary Method (IBM) presents clear advantages for CFD simu lation of compressible ows around complex geometries. In contrast to the standard body- tted approach, in which meshes are designed to conform to geometries, the IBM treats solid obsta cles via local modi cation of the governing equations. Popular modi cations rest on adding volumetric penalization terms to those mesh cells that are covered by immersed bodies [1] or on imposing special boundary conditions on mesh faces surrounding them [2]. In the context of the nodal Discontinuous Galerkin Spectral Element Method (DGSEM), one can also apply subcell based limiting strategies to further discretize the immersed mesh cells employing a compatible low-order method [3]. In this paper, we present a comparison between these three techniques in a high-order setting to solve compressible ows around 2D geometries using the RANS equations with the Spalart-Allmaras one-equation turbulence model. Our results show that introducing wall model-based terms is necessary for IBM formulations to yield correct RANS ow elds, and suggest that subcell-based limiting in the context of IBM can be advantageous in terms of convergence while maintaining solution accuracy.
Abstract
The Immersed Boundary Method (IBM) presents clear advantages for CFD simu lation of compressible ows around complex geometries. In contrast to the standard body- tted approach, [...]
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Local Timestep Super-Time-Stepping Integration Methods Applied to Heat and Mass Transfer in Anisotropic Porous Media
N. Dellinger, G. Dufour, X. Lamboley, L. Reboul, F. Rogier

ECCOMAS 2024.

Abstract
In fire safety problems, the simulation of the thermal degradation of anisotropic porous materials is complex due to the large amplitudes of time and space scales. Degraded areas where temperature increases and gas transport occurs might be very localised, sadly reducing the overall stability of numerical solvers and increasing the computation time. This can be mitigated thanks to Super-Time-Stepping methods, which are based on the use of a multi-step explicit scheme. In this study, these methods are first presented and their advantage to handle diffusion-advection problems such as the thermal degradation of anisotropic porous materials are emphasized on a simple use case. Then, a possible acceleration of the computation by using local timestep Super-Time-Stepping methods, particularly adapted to the heterogeneous problems previously mentioned, is discussed.
Abstract
In fire safety problems, the simulation of the thermal degradation of anisotropic porous materials is complex due to the large amplitudes of time and space scales. Degraded [...]
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A Multigrid preconditioner for Discontinuous Galerkin Methods Applied to Numerical Weather Prediction
P. Birken, A. Dedner, R. Klöfkorn, J. Kasimir

ECCOMAS 2024.

Abstract
High fidelity fluid simulations have important applications in science and engineer ing, examples include numerical weather prediction and simulation aided design. Discontinuous Galerkin (DG) methods are promising high order discretizations for simulating unsteady com pressible fluid flow in three dimensions. Systems arising from such discretizations are often stiff and require implicit time integration. This motivates the study of fast, parallel, low-memory solvers for the resulting algebraic equation systems. For (low order) finite volume (FV) discretizations, multigrid (MG) methods have been suc cessfully applied to steady and unsteady fluid flows. But for high order DG methods applied to f low problems, such solvers are currently lacking. The lack of efficient solvers suitable for contemporary computer architectures inhibits wider adoption of DG methods. This motivates our research to construct a Jacobian-free precondi tioner for high order DG discretizations. The preconditioner is based on a multigrid method constructed for a low order finite volume discretization defined on a subgrid of the DG mesh. Numerical experiments on atmospheric flow problems show the benefit of this approach.
Abstract
High fidelity fluid simulations have important applications in science and engineer ing, examples include numerical weather prediction and simulation aided design. Discontinuous [...]
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Finite Element Simulation of a Rainfall Induced Shallow Landslide in an Experimental Hillslope with a Multiphase Porous Media Model
M. Lazari, M. Camporese, L. Sanavia

ECCOMAS 2024.

Abstract
This study presents the results of a FEM numerical simulation of a large scale physical model of a slope subjected to rainfall infiltration. The slope failure is modelled as a coupled variably saturated thermo-hydro-mechanical problem, using the Pastor-Zienkiewicz generalised plasticity model to obtain the soil’s mechanical response. Small strain and quasi static loading conditions are assumed, and plane strain conditions are adopted in the slope stability analysis. The hydraulic and mechanical parameters are calibrated based on the available experimental data. The numerical results are compared with the experimental data of the mechanical and the hydraulic responses up to failure.
Abstract
This study presents the results of a FEM numerical simulation of a large scale physical model of a slope subjected to rainfall infiltration. The slope failure is modelled [...]
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Impact of saturated granular masses against rigid obstacles: the role of fluid compressibility and front inclination
M. Zerbi, P. Marveggio, C. Prisco

ECCOMAS 2024.

Abstract
In recent years, the impact of saturated granular flows against rigid obstacles has been studied by using different numerical approaches. The very low compressibility of water causes numerical instabilities when impact problems are simulated. In this work, a sensitivity analysis has been done by using a Material Point Method code to assess the influence of fluid compressibility and front inclination on numerical results. When the mass front is inclined, fluid bulk modulus does not significantly affect the solution and can be reduced to speed up the computations and reduce spurious numerical oscillations.
Abstract
In recent years, the impact of saturated granular flows against rigid obstacles has been studied by using different numerical approaches. The very low compressibility of water [...]
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Studies on Effect of Interaction of Coaxial Jets on Thrust of Air-breathing Rocket
T. Sawada, A. Oyama, Y. Maru, H. Manako

ECCOMAS 2024.

Abstract
It is anticipated that the rocket-based combined cycle engine, which incorporates a rocket engine and an airbreathing engine, will offer enhanced propulsive capabilities compared to conventional rocket engines. The exhaust nozzle is a coaxial nozzle comprising a convergent divergent nozzle in the center and a convergent nozzle around it. This represents an unprecedented configuration for a rocket engine nozzle. The objective of this study is to numerically analyze the flow field near the nozzle exit and to elucidate the impact of jet interference on thrust to facilitate the detailed design of rockets. In this study, an airbreathing sounding rocket, currently under research and development at JAXA, is employed as the analysis target. The resulting calculation yielded the flow field data around the nozzle. When the central jet is over-expanded, the velocity and pressure distributions at the nozzle outlet undergo alterations due to the mutual effect of one jet pulling in the other jet. The combined thrust of the two nozzles activated simultaneously was found to be lower than the sum of the individual thrusts of the two cases in which only one of the nozzles was activated. Conversely, the thrust remains constant when the central jet is under-expanded.
Abstract
It is anticipated that the rocket-based combined cycle engine, which incorporates a rocket engine and an airbreathing engine, will offer enhanced propulsive capabilities compared [...]
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Data-driven Permeability Prediction of 3D Fibrous Microstructures
D. Natarajan, T. Schmidt, S. Cassola, M. Nuske, M. Duhovic, D. May, A. Dengel

ECCOMAS 2024.

Abstract
For the manufacturing process simulation of fiber-reinforced polymer composites, f low simulations have to be performed at multiple spatial scales which govern the flow through the fiber structures. Repetitive multiscale flow simulations are computationally expensive and time-consuming. In order to speed up the multiscale simulation workflow, fast machine learning surrogate models or emulators could be used to replace one or more of the flow simulations. In this work, feature-based emulators and geometry-based emulators are developed using neural networks for predicting the permeability of 3D fibrous microstructures based on a reference dataset (doi:10.5281/zenodo.10047095). The best model achieved a mean relative error of 8.33% on the test set with a significantly faster inference time compared to a conventional simulator.
Abstract
For the manufacturing process simulation of fiber-reinforced polymer composites, f low simulations have to be performed at multiple spatial scales which govern the flow through [...]
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Machine learning model for correlating microstructural features and macroscopic properties of heterogeneous composites
H. Zhao, C. Shen, K. Wang, R. Mu, A. Wang

ECCOMAS 2024.

Abstract
This study explores the use of machine learning (ML) models in predicting the macroscopic properties of heterogeneous composites. Traditional micromechanics parameters have limitations, thus ML models with and without feature engineering are utilized. For artificial neural network (ANN) models with feature engineering, microstructural descriptors from SEM images of nickel-based superalloys are used to predict hardness. 10 descriptors are selected to reduce the computational cost of the deep neural network (DNN) with the support of the shallow neural network (SNN), and accuracy is enhanced by incorporating two additional descriptors. The result surpasses existing physics-based models. Models without feature engineering employ a convolutional neural network (CNN) to predict the effective thermal conductivity of thermal insulation composite materials. The CNN model demonstrates accurate predictions for novel microstructures. ML models can achieve more efficient predictions than traditional methods, indicating their potential in advancing materials science. In summary, harnessing artificial intelligence to capture the scattering characteristics of heterogeneous materials enables both DNN and CNN models to achieve more efficient predictions compared to traditional methods. This highlights the potential of machine learning in advancing materials science and expediting the development of materials with desired properties.
Abstract
This study explores the use of machine learning (ML) models in predicting the macroscopic properties of heterogeneous composites. Traditional micromechanics parameters have [...]
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Quasi Gasdynamic Heterogeneous Model for Modeling a Mixture of Compressible Fluids
I. Khaytaliev, E. Shilnikov, T. Elizarova

ECCOMAS 2024.

Abstract
Quasi-gasdynamic type regularization is presented for a heterogeneous model of a two-fluid mixture of compressible fluids. This model allows to describe the flows of stiffened gases. The reduced four-equation model for dynamics of the heterogeneous compressible two fluid mixture with equations of state of a stiffened gas is considered. A further reduced form of this model with the excluded volume concentrations and a quadratic equation for the common pressure of the components can be called a quasi-homogeneous form. A finite difference algorithm is used, built with the finite volume method. By solving one and two dimensional test problems it is shown that the presented algorithm is a stable and reliable way to model fluid mixtures with strong shock waves.
Abstract
Quasi-gasdynamic type regularization is presented for a heterogeneous model of a two-fluid mixture of compressible fluids. This model allows to describe the flows of stiffened [...]
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Deep Reinforcement Learning implementation with Physics-Informed Neural Network for Heat Conduction Control
N. Gonçalves, J. Rodrigues

ECCOMAS 2024.

Abstract
As modern systems become more complex, their control strategy can no longer solely rely on measurement data gathered by instrumentation. Instead, it must also incorporate information derived from mathematical models. The complexity of system models can result in excessively long computation times, making the control process impractical. As a solution, surrogate models are implemented to provide estimates within an acceptable timeframe for decision-making purposes. The surrogate model can be a Physics-Informed Neural Network that is used to obtain the system state on the next time step; such information can be used with a Deep Reinforcement Learning algorithm to train a control strategy based on simulations, replacing the need for running direct numerical simulations. On this work, we explore a Deep Q-Learning strategy on 1D heat conduction problem in which temperature distribution feeds a control system to activate a heat source, aiming to obtain a constant, previously defined temperature value. The main goal is to stabilize the bar temperature at the middle point of it without recurring to numerical simulations.
Abstract
As modern systems become more complex, their control strategy can no longer solely rely on measurement data gathered by instrumentation. Instead, it must also incorporate [...]
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A second-order reproducing kernel for SPH method to enhance accuracy and consistency
I. Wiragunarsa, L. Zuhal, T. Dirgantara, I. Putra

ECCOMAS 2024.

Abstract
The application of smoothed particle hydrodynamics (SPH) encounters challenges related to consistency, stability, and accuracy. Inconsistencies in SPH arise from non-uniform particle distribution and a lack of neighboring particles at the boundary, leading to numerical instability and inaccurate particle approximations. Various methods have been proposed to address these issues. One such framework is the corrected SPH, designed to ensure consistency of the method. In this work, performance of some correction procedures are analysed through gradient calculations of a function. The root mean square error of the gradient approximation is analysed to justify the method’s convergence and accuracy
Abstract
The application of smoothed particle hydrodynamics (SPH) encounters challenges related to consistency, stability, and accuracy. Inconsistencies in SPH arise from non-uniform [...]
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A 3D Particle Model For Reinforced Concrete Fracture Aanalysis
N. Azevedo, M. Farinha, S. Oliveira

ECCOMAS 2024.

Abstract
A numerical model for the analysis of reinforced concrete structures must incorporate tools capable of representing the formation and propagation of cracks, their effect on the overall behavior of the structure, and the interaction between reinforcement and concrete. Detailed rigid particle models (PM) that take directly into consideration the physical mechanisms and the influence of the material aggregate structure have gained relevance and have shown to be able to predict, evaluate and understand cracking phenomena in concrete. The 3D particle models correlate well with experimental results from concrete specimens, particularly in terms of elastic response, peak values, fracture process and fracture location. This paper presents the 3D explicit formulation of steel reinforcement bars using discrete elements with cylindrical geometry. The incorporation of steel elements allows the particle model to be applied to the analysis of fracture in reinforced concrete structures. The rigid elements of cylindrical geometry interact with the concrete, modeled by spherical particles, through a contact interface. The model is validated in three-point beam bending tests, without transverse steel reinforcement. The numerical results obtained show that the proposed model correctly simulates the actual behavior, representing the fracture evolution process and the load displacement relationship for different steel ratios.
Abstract
A numerical model for the analysis of reinforced concrete structures must incorporate tools capable of representing the formation and propagation of cracks, their effect on [...]
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Modeling small scale processes in Antarctic sea ice
R. Pathak, T. Ricken, S. Thoms, S. Seyedpour, B. Kutschan

ECCOMAS 2024.

Abstract
The Antarctic sea ice, which undergoes annual freezing and melting, plays a signif icant role in the global climate cycle. Adverse environmental conditions in the Southern Ocean influence the extent and amount of ice in the Marginal Ice Zones (MIZ), the BioGeo- Chemical (BGC) cycles, and their interconnected relationships. The ’Pancake’ floes are a composition of porous sea ice matrix with interstitial brine, nutrients, and biological com- munities inside the pores. To realistically model these multi-phasic and multi-component coupled processes, the extended Theory of Porous Media (eTPM) is used to develop mod- els capable of simulating the different seasonal variations. All critical variables like salinity, ice volume fraction, and tem perature, among others, are considered and have their equations of state. The phase transition phenomenon is approached through a micro-macro linking scheme. A Phase- field solidification model coupled with salinity is used to model the micro-scale freezing processes and up-scaled to the macro scale eTPM model. This allows for modeling the salt trapped inside the pores. For the biological part, a BGC flux model for sea ice is also set up to simulate the algal species present in the sea ice matrix. Processes like photosynthesis are dependent on temperature and salinity, and are derived through an ODE-PDE coupling with the eTPM model. Academic sim ulations and results are presented as validation for the mathematical model. These high-fidelity models will eventually lead to their incorporation into large-scale global climate models.
Abstract
The Antarctic sea ice, which undergoes annual freezing and melting, plays a signif icant role in the global climate cycle. Adverse environmental conditions in the Southern [...]
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Lightweight AMG preconditioners for CFD simulations on symmetric domains
À. Alsalti-Baldellou, C. Janna, X. Álvarez-Farré, F. Trias

ECCOMAS 2024.

Abstract
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Performance analysis of parallel-in-time techniques in modern supercomputers
J. Plana-Riu, F. Trias, À. Alsalti-Baldellou, G. Colomer, A. Oliva

ECCOMAS 2024.

Abstract
This paper aims to improve the e ciency of large-scale turbulent simulations by improving the arithmetic intensity of the operations. This is done by applying a parallel-in time ensemble averaging technique so that multiple ow states are run simultaneouslly in the same device. This transforms sparse matrix-vector products into sparse matrix-matrix products, improving the arithmetic intensity. The performance of these operations as well as the speed-ups generated in the operation itself, in the whole iteration and an estimation in the whole simulation is presented, so that for cases in which the averaging interval is signi cantlly longer than the transition interval, remarkable speed-ups in the whole iteration are obtained.
Abstract
This paper aims to improve the e ciency of large-scale turbulent simulations by improving the arithmetic intensity of the operations. This is done by applying a parallel-in [...]
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A Hybrid Hexahedral Solid-shell Element with Self-equilibrated Stresses for the Geometrically Nonlinear Static Analysis of Composite Laminated Structures
G. Zucco, F. Liguori, A. Madeo

ECCOMAS 2024.

Abstract
Hybrid nite elements with self-equilibrated assumed stresses have proven to pro vide several advantages for analysing shell structures. They guarantee high performance when using coarse meshes and accurately represent the stress eld. Additionally, they do not require assumptions about the displacement eld within the element domain, and the integration is ef ciently performed only along their contours. This work exploits those advantages to develop a solid-shell nite element for the geometrically nonlinear static analysis of composite laminated structures. In particular, an eight-node nite element, which has 24 displacement variables and 18 stress parameters, is developed. The displacement eld is described only by translations, eliminating the need for complex nite rotation treatments in large displacement problems. A Total Lagrangian formulation is used with the Green-Lagrange strain tensor and the second Piola-Kirchho stress tensor. Thickness locking is cured using an assumed natural strain formu lation for the transversal normal stress, and the assumed stress eld eliminates shear locking. Then, for the analysis of linear-elastic problems, no domain integration is needed, and all the element operators are obtained by line integrals. The resulting formulation is e cient and allows for easy implementation. Computed numerical results show the accuracy and robustness of the presented element when used for both the linear elastic static and geometrically nonlinear elastic static analysis of composite laminated shell structures.
Abstract
Hybrid nite elements with self-equilibrated assumed stresses have proven to pro vide several advantages for analysing shell structures. They guarantee high performance when [...]
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Hierarchic Large Rotation Shell Model with Warping: Isogeometric Formulation and Modeling of Alternating Stiff/Soft Laminates
D. Magisano, A. Corrado, L. Leonetti, J. Kiendl, G. Garcea

ECCOMAS 2024.

Abstract
This paper presents a hierarchic large rotation Kirchho-Love shell model with warping. Two unknowns are introduced for each through-the-thickness function warping, rep resenting its amplitudes in two directions tangent to the shell surface. NURBS are used to approximate reference surface displacement and warping amplitudes in the weak form. The transverse shear strains depend only on the warping parameters linearly and are free from lock ing. A patch-wise reduced integration avoids membrane locking and improves e ciency. Focus is given to composites made up of multiple sti layers coupled with soft interlayers. The alternat ing layup with high sti ness ratios induces a signi cant sectional warping with transverse shear strains concentrated in the soft layers. Two warping models are investigated: WI) all sti layers maintain the same director orthogonal to the deformed surface with independent transverse shear deformations of the soft layers; WZ) a single zigzag function linking these deformations. The numerical tests con rm the great accuracy of the hierarchic shell model in reproducing the solid solution with a small number of discrete parameters, provided that the correct warping model is chosen. WI is reliable for all alternating layups. WZ reduces the unknowns to ve per surface point, regardless of the number of layers, and is accurate for uniform soft layers
Abstract
This paper presents a hierarchic large rotation Kirchho-Love shell model with warping. Two unknowns are introduced for each through-the-thickness function warping, rep resenting [...]
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Recent advances in the postbuckling analysis of composite laminated structures
F. Liguori, G. Zucco, A. Madeo

ECCOMAS 2024.

Abstract
The current demand for lightweight structures in a wide range of engineering appli cations leads to using thin-walled composite laminated structures whose behaviour is governed by buckling and postbuckling phenomena. Such a demand is pushing the borders of computational mechanics to enhance methods and algorithms for studying those structures' geometrically non linear responses. This work presents some of the authors' developments in analysing lightweight composite laminated structures. The literature survey introduces a family of nite elements known as MISS elements, where MISS stands for mixed isostatic self-equilibrated stresses. The description of those elements, which are derived from the Hellinger-Reissner functional, is followed by a discussion on their advantages concerning displacement-based elements when studying com posite laminated thin-walled structures. Subsequently, a framework for the postbuckling analysis of composite structures with the MISS-4C element that uses the Koiter multi-modal approach is presented.
Abstract
The current demand for lightweight structures in a wide range of engineering appli cations leads to using thin-walled composite laminated structures whose behaviour is governed [...]
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Post-buckling behaviour and delamination growth in defected variable angle tow composite laminates
D. Gaetano, F. Greco, L. Leonetti, A. Pranno, G. Zucco

ECCOMAS 2024.

Abstract
Due to their specific strength and stiffness properties, composite materials are largely used in lightweight structural applications in aerospace, automotive and mechanical engineering. Understanding how these materials fail under service loads is a challenging aspect of designing advanced composite structures. In fact, the failure of composite laminated structures is often governed by complex interactions of multiple interlaminar failure and damage mechanisms. Among them, delamination is one of the damage modes requiring large attention due to the low interlaminar resistance between the different layers comprised in a composite laminate. In addition, this phenomenon may be triggered by defects introduced in the construction phase or by the presence of connections leading to stress concentrations. When coupled with buckling phenomena, delamination inevitably decreases the load-carrying capacity of lightweight composite structures. Variable Angle Tow (VAT) laminates have been proven to improve the buckling and post-buckling response of those structures significantly. However, little is known about the geometrically nonlinear behaviour of VAT composite laminates with delaminations. This work applies the cohesive finite element method to model delamination growth in VAT composite laminates containing initial defects under compressive loading conditions. Numerical simulations investigate the effects of the fibre angle variation on the geometrically nonlinear static response of VAT composite laminates compared to that of their classical straight fibre counterparts.
Abstract
Due to their specific strength and stiffness properties, composite materials are largely used in lightweight structural applications in aerospace, automotive and mechanical [...]
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Numerical and analytical evaluation of resin flow during PCB pressing cycles
C. Schipfer, J. Zuendel, Q. Tao, T. Krivec, P. Fuchs, M. Gramueller

ECCOMAS 2024.

Abstract
This paper presents a comprehensive sequence of analytical methods for evaluating printed circuit board (PCB) pressing processes, augmented by numerical finite element (FE) simulations. The study considers the properties of the prepreg material, the structure of the PCB copper layer, and various pressing process parameters, all of which can be adjusted according to specific requirements. Our results are validated through experiments and compared with the established Squeeze Flow Model. The pro posed methodology identifies potential weaknesses in the design of the copper layer, material selection, and pressing parameters prior to production. Additionally, the implementation of this methodology in an interactive user interface allows for rapid and efficient results, facilitating timely decision-making and process optimization
Abstract
This paper presents a comprehensive sequence of analytical methods for evaluating printed circuit board (PCB) pressing processes, augmented by numerical finite element (FE) [...]
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Computational analysis of non-proportional biaxial shear reverse experiments superimposed by different cyclic loads
Z. Wei, S. Gerke, M. Brünig

ECCOMAS 2024.

Abstract
This paper deals with anisotropic ductile damage and fracture behavior under low positive stress triaxialities. Novel tension–shear biaxial low–cycle experiments with different numbers of loading cycles (up to twenty) have been performed using a cruciform biaxially loaded specimen. During the experiment, a tensile preload is first imposed on the horizontal axis until it reaches 3kN; then, it is kept constant while different shear cyclic loading sequences are superimposed on the vertical axis until failure. All cyclic loadings are driven to a large strain range to investigate ductile damage, and the same amplitude is maintained for each repeated reverse loading cycle within a single loading pattern. In addition, numerical simulations are performed with an anisotropic stress-state-dependent plastic-damage continuum model, also considering the Bauschinger effect. The experimental and numerical analysis of the evolution of the first principal total strain and damage strains highlights the influence of the cyclic loading history on the material behavior. Moreover, fracture surfaces are examined by scanning electron microscopy to analyze the different mechanical performances at the micro-level
Abstract
This paper deals with anisotropic ductile damage and fracture behavior under low positive stress triaxialities. Novel tension–shear biaxial low–cycle experiments with [...]
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Adaptive Refinement Techniques using Multiresolution Wave Propagation Simulations Guided by Inherent Convergence Indicators
D. Dimitriou, A. Samara, D. Saravanos

ECCOMAS 2024.

Abstract
The multiresolution finite wavelet domain method has been meticulously studied in wave propagation simulations. The multiresolution procedure always starts with the coarse solution, and then finer solutions can be superimposed on the coarse solution, until convergence is achieved. Based on remarkable observations on the multiple resolution components of the method, a residual-based convergence indicator that reveals convergence at the coarse solution is developed. This convergence metric is rapidly applicable and straightforward and can also divulge the spatial and temporal ranges/domains that the already obtained solution needs to be enhanced. In that way, an automatic adaptive refinement technique is proposed for the local enrichment of the solution, only in the specific grid points and time-steps that it is needed. A numerical case study regarding wave propagation in an inhomogeneous rod manifests the effectiveness and accuracy of the proposed automatic refinement methodology, as also the performance of the suggested convergence indicator.
Abstract
The multiresolution finite wavelet domain method has been meticulously studied in wave propagation simulations. The multiresolution procedure always starts with the coarse [...]
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Seismic Performance Assessment of Bouçã Arch Dam. Non-Linear Analysis Considering Joint Movements and Concrete Damage Under Tension and Compression
S. Oliveira, A. Alegre, C. Serra, R. Ramos, J. Silva, J. Proença, P. Mendes

ECCOMAS 2024.

Abstract
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Simultaneous, Dynamical Analysis of Structural Ropes and Membranes on all Level-sets
T. Fries, M. Kaiser

ECCOMAS 2024.

Abstract
Thelevel sets of scalar functions may imply the geometries of individual ropes and membranes. All level sets within an interval, considered in some bulk domain, define infinitely many geometries at once. A mechanical model is proposed which enables the simultaneous, dynamic analysis of all such geometries. For the solution of the governing equations, a tailored numerical method coined Bulk Trace FEM is employed for the spatial discretization, using higher-order background meshes in the bulk domains. The HHT-α method is used for the temporal discretization. Numerical results are presented that demonstrate the potential of the proposed mechanical model and numerical method
Abstract
Thelevel sets of scalar functions may imply the geometries of individual ropes and membranes. All level sets within an interval, considered in some bulk domain, define infinitely [...]
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Micro-scale analysis of rough surfaces using non-conforming meshes
M. Oliveira, D. Neto, L. Menezes

ECCOMAS 2024.

Abstract
This work presents a finite element model of the contact between a flat rigid surface and a rough deformable elastoplastic body, enabling the micro-scale analysis of the contact conditions. To assure the computational efficiency a non-conforming mesh is adopted to describe the deformable body. The results show that the model can capture the main effects of the bulk material constitutive behaviour, which is known to have a significant impact on the problem, as well on local changes on the friction conditions.
Abstract
This work presents a finite element model of the contact between a flat rigid surface and a rough deformable elastoplastic body, enabling the micro-scale analysis of the contact [...]
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Offline and Online Performance Contrast of Optimal Control
M. Miah, W. Lienhart

ECCOMAS 2024.

Abstract
Civil structures are quite vulnerable to extreme dynamic loads as well as to nat ural disasters. The aforementioned problem is well-known and interestingly, unavoidable as it is almost impossible to know when that type of loads or disasters are going to hit the existing structures. Due to such unpredictability, many are interested to adopt the online or real-time control and monitoring strategy instead of conventional approach. However, still offline moni toring and vibration control strategies are useful to understand the overall performance of the investigated dynamical problem as it might not be an option to go for online due to feasibility or other constrains. In order to hold a debate, herein, the controlled performance of a multi degree-of-freedom system has investigated both adopting offline and online approaches. The linear-quadratic regulator (LQR) algorithm has been employed as the control law and it is as sumed that controller will behave as an active control system. In order to understand the effect of the optimal control, the displacements and velocities at different degree-of-freedom’s level have considered and compared. The outcome suggests that both approaches have advantages and disadvantages such as offline approach is quite useful to understand at the design phase of the project, while, online approach might be very effected after the construction.
Abstract
Civil structures are quite vulnerable to extreme dynamic loads as well as to nat ural disasters. The aforementioned problem is well-known and interestingly, unavoidable as [...]
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Determination of Neutral Axis and Effect of the Variation of Cross Sectional Area on the Mechanical Properties of Smart Meta-Structure
S. Sahana, A. Singh, B. Bhattacharya

ECCOMAS 2024.

Abstract
In recent years, manufacturing has paved the way to enhance structural properties using 3D printed structures by constructing complex shapes. The properties of such structures depend on the arrangement of the internal lattices. Honeycomb is one such simple lattice struc ture that is widely used by researchers as it exhibits a high strength-to-weight ratio. However, the elastic properties of the lattice structures are intrinsic functions of the material properties and the geometric shape. Hence, it is impossible to modulate the elastic properties once constructed. Recent studies have shown that the active modulation of the elastic properties can be achieved by incorporating smart materials over the substrate layers of the lattice. The analytical expressions have been developed for honeycomb/ auxetic honeycomb lattice considering the Euler-Bernoulli bi-layer beam to determine its elastic properties. The expression is well valid for lattices where the thickness of the smart material is relatively less compared to the substrate thickness. How ever, it does not produce consistent results as the thickness of the smart material increases due to the shift of the position of the neutral axis, which was earlier assumed to be at the geomet ric centre of the substrate beam. This paper presents a modified formulation that considers the change in the position of the neutral axis as the thickness of the smart material patches varies. This modification allows the use of the analytical expression for beams with higher thickness ratios and can be used to understand the impact of forces in shear deformation. In addition, the variation in the elastic properties has also been investigated for different cross-sectional shapes such as I-section, T-section, and rectangular cross-section. The formulation presented here is generic, and the concept can be used in various futuristic multi-functional structural systems and devices across different length scales
Abstract
In recent years, manufacturing has paved the way to enhance structural properties using 3D printed structures by constructing complex shapes. The properties of such structures [...]
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ψ − flow: A Novel Physics-Constrained Architecture to Enforce Incompressibility and Boundary Conditions for Fast and Accurate Flow Predictions
M. Cabral, B. Font, G. Weymouth

ECCOMAS 2024.

Abstract
Deeplearning models have demonstrated remarkable capabilities at producing fast predictions of complex flow fields. However, incorporating known physics is essential to ensure that physical solutions can generalize to flow regimes not used for training. In this study, a formulation that, by construction, enforces flow incompressibility and respects the invariance of physical laws across different unit systems is introduced. We demonstrate that this approach can achieve performance improvements of up to 100 times compared to purely data-driven methods, all while maintaining fidelity to other crucial physical quantities. Moreover, we show that for canonical flow test cases, such a physics-constrained model can yield accurate results even with training datasets as small as a few hundred points and neural networks containing only a handful of neurons. It is also shown, however, that physics-constrained machine learning models are not silver bullets out of the box, and require careful consideration in their application and integration with other constraints. Specifically, this study addresses how a problem that is mathematically simple may not necessarily be straightforward in machine learning terms, and discusses ongoing efforts to bridge this gap. We conclude by discussing the place of physics-constrained machine learning models within a landscape primarily dominated by physics-informed approaches, in particular in the context of real-world problems where data and computational resources are often limited
Abstract
Deeplearning models have demonstrated remarkable capabilities at producing fast predictions of complex flow fields. However, incorporating known physics is essential to ensure [...]
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On the Usage of PANS for the CFD Simulation of Wind Turbines
T. Gomes, G. Vaz, A. Maximiano, L. Sileo, V. Krasilnikov

ECCOMAS 2024.

Abstract
With the rapid evolution of o↵shore wind energy, engineering tools are crucial to catalyze technological developments and increase their maturity, therefore leading to lower costs. Complex turbine-turbine interactions require a good knowledge of the physics of the flow on, around and down/upstream of each turbine, which can be provided using high-fidelity CFD simulations. Turbulence models play a critical role on this matter and an adequate balance between accuracy and computational e ort is necessary. While RANS approaches are quite e cient, LES should provide the most accurate result. Yet, even nowadays, LES blade-resolved simulations are still computationally prohibitive for industrial purposes. A middle-ground exists in SRS formulations, such as hybrid ones as DDES, or bridging ones such as PANS. In the present work emphasis is placed on PANS, since numerical and modelling errors can be studied and quantified independently, as opposite to other SRS approaches. Using as a benchmark the UNAFLOWwindturbine, it is found that traditional RANS and DDES turbulence formulations are able to predict integral forces, but partially fail in capturing wake mixing. Nevertheless, PANS, while enabling the user to select the ratio of turbulent quantities modelled, is not able to properly capture the integral forces due to premature separation in the blades. Several causes are discussed, including insu cient mesh refinement in the near-wall region and lack of turbulent content of the numerical inlet, preventing laminar to turbulent flow transition. Future work should focus on inlet synthetic turbulence generation, in line with existent literature, in order to improve the shortcomings faced in properly resolving the near-wall flow.
Abstract
With the rapid evolution of o↵shore wind energy, engineering tools are crucial to catalyze technological developments and increase their maturity, therefore leading [...]
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ENERGÍA NUCLEAR: UNA ALTERNATIVA VÁLIDA PARA LAS INVERSIONES SOSTENIBLES - FULL PAPER
M. Carrasquer

Marta Carrasquer's personal collection (2024). 1

Abstract
En medio de la crisis climática y la demanda de soluciones sostenibles, la energía nuclear ha resurgido como una opción clave para reducir las emisiones de carbono sin comprometer la generación energética. No obstante, enfrenta desafíos como la percepción pública, los riesgos de accidentes y la gestión de residuos radiactivos. A pesar de no emitir dióxido de carbono durante su operación, su papel en la transición hacia una economía de bajas emisiones depende de superar tanto barreras técnicas como prejuicios sociales. Este estudio explora cómo la energía nuclear puede contribuir de forma efectiva y sostenible en la lucha contra el cambio climático. Y a la vez, investiga la viabilidad de la energía nuclear dentro del ámbito de las inversiones sostenibles, detallando un universo de inversión en tecnologías nucleares e instrumentos financieros que apoyan la transición hacia un futuro energético descarbonizado.
Abstract
En medio de la crisis climática y la demanda de soluciones sostenibles, la energía nuclear ha resurgido como una opción clave para reducir las emisiones [...]
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Organismos y empresas colaboradoras
libro-blanco-materiales-compuestos (2024). 58
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The Influence of Bilingualism in Altering the Cortical Executive Functions of Adolescents
A. Shah

Collection of Articles on Psychology (2024). 3

Abstract
195 countries, 7,000+ officially known languages, thousands of hidden dialects. When we think of languages, words that come to mind are often related to communication. Especially with knowing multiple languages, we think of amplifying relations with interpersonal communication. Yet, a problem exists with the lack of knowledge about bilingualism’s advantage besides these perceptions in globalized societies. This issue impacts monolinguals because of decreasing language education neglecting bilingualism’s increase of cognitive skills. Limited research on the benefits of bilingualism among adolescents exacerbates this problem, as existing studies often focus on infants and older adults, considering these age groups depict clear benefits without confounding variables. However, adolescents have the greatest adaptability for language acquisition, asserting suitability in measuring bilingualism before brain development hinders learning abilities in adulthood (Smith, 2018). The purpose of this study is to underscore the beneficial advantage bilingualism—specifically among adolescents—provides unconsciously daily, ultimately aiding to promote language education.
Abstract
195 countries, 7,000+ officially known languages, thousands of hidden dialects. When we think of languages, words that come to mind are often related to communication. Especially [...]
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Multicolor Parallel Fourth-Order Implicit Finite Difference for Solving the 2D Poisson Equation
M. Zapata, R. Balam, H. Puc

SMCCA (2024). 3

Abstract
The Poisson equation is central in numerous physics and engineering applications, such as computational fluid dynamics and acoustic wave propagation, where efficient and accurate solutions are essential. This study focuses on the numerical solution of the 2D Poisson equation with Dirichlet boundary conditions using a fourth-order compact Implicit Finite Difference scheme. Finite difference methods, particularly high-order schemes, are advantageous for solving the Poisson equation due to their efficiency and suitability for structured grids. To address the computational demands of large-scale problems, we incorporate domain decomposition and the Multicolor Successive Over Relaxation method, facilitating parallel computation. Through numerical experiments, we demonstrate that our approach significantly enhances both accuracy and computational efficiency when compared to traditional second-order methods.
Abstract
The Poisson equation is central in numerous physics and engineering applications, such as computational fluid dynamics and acoustic wave propagation, where efficient and accurate [...]
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L’impacte i el desenvolupament ordenat de l’economia col.laborativa com a un fenòmen econòmicament determinant.
M. Alarcón, G. Congrés2025

Abstracts_4rceec (2024). 222

Abstract
Eix 3: La musculatura del sistema empresarial català L’impacte i el desenvolupament ordenat de l’economia col.laborativa com a un fenòmen econòmicament determinant. Abstract L’economia col.laborativa, redefinida com a economia de plataformes és un fenomen emergent que utilitza la tecnologia i l’entorn digital per proporcionar serveis atractius i/o productes desintermediant i disrumpint l’statu quo de moltes indústries, inclús creant-ne de noves. Cada any s’inverteixen milers de milions d’euros en aquesta nova economia arreu del món fent créixer el fenomen i expandint-lo de forma exponencial. Catalunya és seu d'algunes d’aquestes empreses, tant startups de producció pròpia com scaleups d’origen internacional donant pas així a un nou sector d’activitat econòmica lligat a les noves tecnologies digitals. La velocitat amb què el sector tecnològic i digital en l’àmbit de l’economia de plataformes evoluciona els seus models de negoci i la seva implementació per part dels usuaris planteja un gran repte tant de seguiment i comprensió com de predicció i prevenció a temps dels seu impacte. Hem estat testimonis de com els perjudicis que el desconeixement, el destemps o la manca d’adequació a la regulació existent poden afectar a un sector enguany tan determinant. Amb l’objectiu d’evitar aquests desajustos i de permetre un desenvolupament de l’economia de plataformes sostenible, racional i beneficiós per Catalunya i els seus ciutadans i ciutadanes, és imperiós conèixer el sector, les seves necessitats, els seus actors principals i les tendències que cal tenir en compte.
Abstract
Eix 3: La musculatura del sistema empresarial català L’impacte i el desenvolupament ordenat de l’economia col.laborativa com a un fenòmen [...]
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Fatigue delamination damage analysis in composite materials through a rule of mixtures approach
A. Taherzadeh-Fard, S. Jiménez, A. Cornejo Velázquez, E. Oñate, L. Barbu

Composite Structures (2024). Vol. 351, 118613

Abstract
The present study investigates delamination damage initiation and propagation within a homogenization theory of mixtures, using the concept of virtual layers and virtual interfaces. It eliminates spatial discretization of layers, introducing a resultant damage variable to capture structure’s bulk response under both monotonic and cyclic loads. Fatigue-induced deterioration is classified into sub-critical, critical, and over-critical stages based on interfacial stresses. Calibration is conducted employing the widely-available Wöhler curves for each loading mode independently. An advance-in-time strategy is included in the model to enhance the simulation speed. The reliability of the approach is assessed for crack initiation and propagation separately through standard test coupons, showing good correlation with experimental data in mode I, mode II, and mixed-mode loading conditions. Depending on the calibration procedure adopted, the model is applicable to a wide range of stress ratios. In addition, it could be integrated into any standard finite element framework using the desired number of elements through the thickness regardless of the physical amount of layers. This allows easy modification of stacking sequences or the number of layers within the constitutive law without mesh structure changes, facilitating simulation of large-scale composite laminates with minimal accuracy loss and reduced computational costs.
Abstract
The present study investigates delamination damage initiation and propagation within a homogenization theory of mixtures, using the concept of virtual layers and virtual interfaces. [...]
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Multiscale data-driven modeling of the thermomechanical behavior of granular media with thermal expansion effects
R. Rangel, A. Franci, E. Oñate, J. Gimenez

Computers and Geotechnics (2024). Vol. 176, 106789

Abstract
A multiscale data-driven (MSDD) methodology is proposed for simulating the thermomechanical behavior of granular materials subjected to thermal expansion. The macroscale is handled using a continuous model based on the Finite Volume Method (FVM), while the microscale response is captured at Representative Volume Elements (RVEs) with the Discrete Element Method (DEM). To significantly reduce the computational cost of the analyses, the microscale DEM computations are not performed online, �.�., simultaneously with the macroscale FVM ones, as generally done in standard multiscale approaches. Instead, they are performed in advance to create a comprehensive database of RVE solutions under different initial conditions and thermal strains. This dataset is then used to train an Artificial Neural Network (ANN), which serves as a surrogate model for the macroscale solver. The MSDD approach is validated against pure DEM solutions of problems with distinct thermal conditions. Remarkably, we demonstrate that with only three input parameters, namely porosity, fabric, and thermal strain, the surrogate model can predict the microstructure evolution, as well as the updated conductivity and Cauchy stress tensors of the granular assembly. This allows for a generally accurate simulation of transient thermomechanical analyses at a drastically lower computational cost than the pure DEM approach.
Abstract
A multiscale data-driven (MSDD) methodology is proposed for simulating the thermomechanical behavior of granular materials subjected to thermal expansion. The macroscale is [...]
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A critical review of how eXtended Reality (XR) has addressed key factors influencing Safety on Construction Projects (fSCPs)
F. Rivera, J. Mora, E. Oñate

Archives of Computational Methods in Engineering (2024). Vol. 31, pp.s 2015–2048

Abstract
The construction industry is known for its high accident rates. One hundred key factors affecting construction safety (fSCPs)—associated with general aspects of organisational management, materials and equipment, the construction site, and human aspects related to the worker and work team—have been identified. EXtended Reality (XR), which encompasses Virtual Reality (VR), Augmented Reality (AR), and Mixed Reality (MR) technologies, is being used in construction safety management. XR offers multiple advantages, given its characteristics of visualisation, immersion, and interaction with digital models and real objects. XR’s potential safety uses are widely recognised, and several studies have tested these technologies for different applications. However, most such efforts have been focused on identifying functionalities, applications, and technological aspects of XR in general, rather than studying whether those uses affect the factors relevant to security management. This study examined the literature on XR experiences that have addressed fSCPs and analysed how these developments have been related to the construction sector’s methodologies and technologies, such as building information modelling (BIM).
Abstract
The construction industry is known for its high accident rates. One hundred key factors affecting construction safety (fSCPs)—associated with general aspects of organisational [...]
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A continuum–discrete multiscale methodology using machine learning for thermal analysis of granular media
R. Rangel, J. Gimenez, E. Oñate, A. Franci

Computers and Geotechnics (2024). Vol. 168, Art. Num. 106118

Abstract
This work presents a data-driven continuum–discrete multiscale methodology to simulate heat transfer through granular materials. The two scales are hierarchically coupled, where the effective thermal conductivity tensor required by the continuous method at the macroscale is obtained from offline microscale analyses. A set of granular media samples is created through the Discrete Element Method (DEM) to relate microstructure properties with thermal conductivity. The protocol for generating these Representative Volume Elements (RVEs) and homogenizing the microscale response is presented and validated by assessing the representativeness of the granular assemblies. The study found that two local properties, the porosity and the fabric of the material, are sufficient to accurately estimate a representative thermal conductivity tensor. The created dimensionless database of microscale results is used for training a surrogate model based on machine learning. In this way, effective thermal conductivity tensors that accurately reflect the local microstructure can be efficiently predicted from the surrogate model by taking the microstructural properties as inputs. The proposed multiscale methodology enables us to solve heat problems in granular media using a continuum approach with accuracy comparable to a pure discrete computational method but at significantly reduced computational cost.
Abstract
This work presents a data-driven continuum–discrete multiscale methodology to simulate heat transfer through granular materials. The two scales are hierarchically [...]
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A modified Johnson–Cook model for the plastic behavior of metals in ultrasonic vibration-assisted upsetting processes
H. Bakhshan, J. Carbonell, E. Oñate

Journal of Manufacturing Processes (2024). Vol. 121, pp. 361-373

Abstract
In this work, we present a constitutive description of the plastic behavior of the metals and alloys under Ultrasonic Vibration (UV). When UV is imposed, it induces a softening effect on the plastic deformation of metals and alloys, referred to as the acoustoplastic phenomenon. The volumetric softening mechanism of the acoustoplasticity must consider stress superposition and acoustic softening. Taking the Johnson–Cook (JC) constitutive model as the reference for metal thermo-plasticity, the flow stress reduction due to UV is introduced by three types of softening terms: subtractive, multiplicative, and coupled. Those different configurations will be quantified via physical and phenomenological assumptions. For the study and validation of the proposed constitutive models, we focus on a well-known material, 6063 aluminum alloy. The ultrasonic vibration is modeled by an assisted upsetting process of an aluminum billet and compared with experiments. The impact of variations of the strain rate, ultrasonic amplitude, and frequency on the softening behavior of the models are analyzed and compared with available experimental results. We find out that the subtractive and coupled models agreed well with the experimental results showing the errors ranging from 2.4–4.8% and 4.4%–8%, respectively. However, the predictive ability of the multiplicative model exhibits large discrepancies at the low stage of strains following the acceptable predictions at high stains. By understanding the impact of the UV on the acoustoplastic deformation of the metals and alloys we can establish a reliable theoretical framework for prospective numerical studies of the UV-assisted manufacturing processes which is the goal of the current research presented here.
Abstract
In this work, we present a constitutive description of the plastic behavior of the metals and alloys under Ultrasonic Vibration (UV). When UV is imposed, it induces [...]
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Hydromechanical embedded finite element for conductive and impermeable strong discontinuities in porous media
D. Cavalcanti, C. Mejia, D. Roehl, I. de-Pouplana, E. Oñate

Computers and Geotechnics (2024). Vol. 172, 106427

Abstract
The pore pressure inside oil and gas reservoirs compartmentalized by sealing faults increases during injection processes. The rise in the pore pressure can induce fault reactivation, leading to hydraulic issues such as fluid leakage from the reservoir to other layers and seismicity. Therefore, it is essential to accurately model the mechanisms involved in this problem, primarily related to the presence of a strong discontinuity, a fault, inside the domain. Several numerical approaches can be used to represent the presence of discontinuities. The embedded finite element method (EFEM) has recently gained attention because it does not require the mesh to conform with the discontinuities, thus circumventing the typical mesh generation challenges of modeling faulted domains. The current EFEM formulations cannot properly model a hydromechanical problem such as fault reactivation, due to simplifications in their derivation. Hence, this work proposes a new fully coupled hydromechanical EFEM formulation based on the Strong Discontinuity Approach that can represent discontinuities acting as preferential flow paths or barriers for the fluid flow. The formulation is applied to a fault reactivation problem, showing the main reactivation mechanisms. This paper also discusses the presence of spurious oscillations along the discontinuities and their relations with the mesh discretization.
Abstract
The pore pressure inside oil and gas reservoirs compartmentalized by sealing faults increases during injection processes. The rise in the pore pressure can [...]
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The P-DNS method for turbulent fluid flows: An overview
S. Idelsohn, J. Giménez, A. Larreteguy, N. Nigro, F. Sívori, E. Oñate

Archives of Computational Methods in Engineering (2024). Vol. 31, pp. 973–1021

Abstract
An overview of the Pseudo-Direct Numerical Simulation (P-DNS) method is presented. This is a multi-scale method aiming at numerically solving the unknown fields at two different scales, namely coarse and fine. The P-DNS method is built around four key ideas. The first one is that of numerically solving both scales, which facilitates obtaining solutions to problems of both concurrent multi-scale and hierarchical multi-scale types. The second key idea is that of computing off-line the fine solution via Direct Numerical Simulation in simplified domains, termed representative volume elements (RVEs), while the third idea is that of storing the basic (physics-informed) results obtained from this solution in a problem-independent unique dimensionless database. This database may be subsequently used for solving different problems at the coarse level, i.e. by using coarse meshes in the corresponding problem domains, via a surrogate model. In this sense P-DNS resembles Reduced Order Methods, which require a previous off-line evaluation of the modes to be used in the solution, sharing with them the benefit of solving the reduced problem, more precisely the coarse scale, in P-DNS terms, in a very efficient way. The fourth and last key idea of P-DNS is based on the fact that most of the high-frequency modes of a turbulent flow are convected by the fluid velocity of the low-frequency modes. Taking this into account the P-DNS technique is implemented in such a way that the fine instabilities are convected by the velocity field of the coarse solution. Finally, although the P-DNS method has been used to solve different computational mechanics problems, such as convection-diffusion and convection-reaction/absorption problems, the scope of this overview will be limited to its application to turbulent incompressible fluid flows, including both single phase and particle-laden flows.
Abstract
An overview of the Pseudo-Direct Numerical Simulation (P-DNS) method is presented. This is a multi-scale method aiming at numerically solving the unknown fields at two different [...]
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Microstructure evolution modeling of Ti6Al4V alloy during cutting using the Particle Finite Element Method and homogeneous field distributions
H. Bakhshan, E. Oñate, J. Carbonell

Journal of Manufacturing Processes (2024). Vol. 131, pp. 73-92

Abstract
This paper aims to explore the evolution of microstructural parameters induced during the cutting of Ti6Al4V alloy (TC4). The microstructure characteristics of the workpiece material is directly tied to its mechanical response during machining. During TC4 cutting, microstructure evolution is observed as a result of severe plastic deformations. The characterization of this phenomenon has significant interest from both academia and industry. In this work we present a developed modeling technique which combines the Particle Finite Element Method (PFEM) with incremental homogeneous field distributions. First, the PFEM is extended to perform a thermo-mechanical analysis capable of capturing the material responses of TC4 during orthogonal cutting. To generate serrated chips, an appropriate strain softening-based constitutive plasticity model i.e., TANH (Hyperbolic TANgent) is utilized. The PFEM’s validity is checked through comparison with available experimental results in terms of chip shapes and cutting forces. Second, the evolution of microstructural parameters such as dislocation density, vacancy concentration, dynamic recrystallization (DRx) grain size, and hardness is incrementally developed and incorporated into the PFEM using internal state variables as homogeneous field distributions. The Johnson–Mehl–Avrami–Kolmogorov (JMAK) model and Hall–Petch equation are applied for predicting grain size and hardness, respectively. The parameters of the corresponding models are modified for TC4 to accurately capture their alterations. Lastly, the predicted results of the microstructure evolution in serrated chips and machined surfaces, including average grain size and hardness, are compared with experiments, demonstrating good agreement. This implies that the PFEM combined with microscale schemes can reliably simulate the machining process of the TC4.
Abstract
This paper aims to explore the evolution of microstructural parameters induced during the cutting of Ti6Al4V alloy (TC4). The microstructure characteristics of the workpiece [...]
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Modeling of ultrasonic vibration-assisted micromachining using the particle finite element method
H. Bakhshan, E. Oñate, J. Carbonell

Computational Particle Mechanics (2024). Published Online, June 2024

Abstract
When metals and alloys are exposed to ultrasonic vibrations (UV), a softening behavior occurs, caused by the phenomenon of acousto-plasticity. To obtain accurate results in a deformation analysis, this phenomenon must be included in the formulation of the constitutive material model. In this work, an acoustic-plastic model is proposed to capture the effects of ultrasonic vibrations during machining. The desired effect is to modify the chip morphology to reduce the magnitude of the cutting forces and thus reduce the energy consumption of the process. The study focuses on the modeling of ultrasonic vibration-assisted micromachining (VAMM). The particle finite element method is used and extended to perform a thermo-mechanical analysis capable of capturing the responses of conventional micromachining (CMM) and VAMM operations of 32 HRC stainless steel. The cutting speed and UV parameters, including amplitude and frequency, are integrated into the Johnson–Cook constitutive model to account for the effects of acoustic softening on the machining characteristics. The results show that the influence of UV on microcutting leads to thinner chips and lower cutting force. In the VAMM operations, an average reduction in cutting forces of 20% is achieved at five different cutting speeds. In addition, the contact length between the tool and chip decreases at different cutting speeds from 29% to a maximum of 44%. Furthermore, the thermal analysis results show that there is a negligible temperature change during the CMM and VAMM simulations, indicating that the study of the machining process can focus exclusively on its mechanical aspects when performed at the microscale. The predicted average chip thickness and effective shear angle of the workpiece material are in strong agreement with the experimental results, emphasizing the importance of considering acoustic softening in VAMM studies.
Abstract
When metals and alloys are exposed to ultrasonic vibrations (UV), a softening behavior occurs, caused by the phenomenon of acousto-plasticity. To obtain accurate results in [...]
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Fast explicit time integration schemes for parabolic problems in mechanics
E. Oñate, F. Zarate, J. Gimé, F. Paulet-Crainiceanu, S. Idelsohn

International Journal for Numerical Methods in Engineering (2024). Vol.125 (13), e7477

Abstract
We present a family of fast explicit time integration schemes of first, second and third order accuracy for parabolic problems in mechanics solved via standard numerical methods that have considerable higher computational efficiency versus existing explicit methods of the same order. The derivation of the new explicit schemes is inspired on the finite increment calculus (FIC) procedure used for obtaining stabilized numerical schemes in fluid and solid mechanics. The new (so-called) explicit FIC-Time (EFT) schemes allow considerable larger time steps than the standard first order forward Euler (FE) scheme and the second and third order Adams–Bashforth schemes. The comparison with Runge–Kutta schemes also favors the FIC-Time schemes in terms of the limit time step size (for second order schemes) and the total number of matrix-vector multiplications per time step (for second and third order schemes). The new first order explicit schemes have a faster convergence to steady-state than the FE scheme. The accuracy and efficiency of the new EFT schemes are verified in examples of application to the transient heat conduction equation using the finite element method.
Abstract
We present a family of fast explicit time integration schemes of first, second and third order accuracy for parabolic problems in mechanics solved via standard numerical methods [...]
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Efficient discrete element modeling of heat generation and transfer in granular flows: Validation and application
R. Rangel, A. Franci, E. Oñate

Powder Technology (2024). Vol. 439, Art. Num. 119719

Abstract
This work presents an efficient Discrete Element Method (DEM) framework for the simulation of the thermal behavior of granular media. The main focus is on long-lasting granular flows, involving heat transfer and generation due to mechanical energy dissipation. The proposed approach uses efficient strategies to reduce the computational cost of the analyses and, therefore, to enable its application to problems of practical relevance. For instance, the contact area is adjusted to compensate for the artificial material softening that is typically considered in DEM to increase the time step size. After extended validation, the methodology is applied to the simulation of different setups of an experimental rotating drum. The numerical simulations presented good agreement with the experimental results and allowed a detailed analysis of the mechanisms and patterns of heat generation, which could not be extrapolated from the experimental campaign.
Abstract
This work presents an efficient Discrete Element Method (DEM) framework for the simulation of the thermal behavior of granular media. The main focus is on long-lasting granular [...]
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A review of the constitutive modelling of metals and alloys in machining process
H. Bakhshan, E. Oñate, J. Carbonell

Archives of Computational Methods in Engineering (2024). Vol. 31(3), pp. 1611-1658

Abstract
Conventional machining still represents a predominant manufacturing process for the production of metal parts. During the last few decades, extensive research has been conducted to develop predictive models to capture complex material response during the machining process. Understanding the plastic behavior of the metals and alloys during machining operations has a great significance for researchers and engineers in both academia and industry. This paper thoroughly reviews the constitutive material models that have been employed thus far in the conventional machining studies. The aim of the paper is to present all significant constitutive models focusing the discussion on the most frequently used. First, we introduce the phenomenological models that depend on the deformation variables including strain, strain rate and temperature. Several extended versions proposed in the literature of these types of models will be reviewed. The techniques to identify the material constant parameters will also be discussed. Second, the proposed physical-based models, a kind of model that relies on the evolution of internal state variables, including dislocation density and grain size, will be addressed. Following that, novel data-driven based constitutive models are briefly debated to highlight their capabilities in order to be exploited in machining analysis. Finally, a concise overview and perspectives for future research efforts are outlined.
Abstract
Conventional machining still represents a predominant manufacturing process for the production of metal parts. During the last few decades, extensive research has been conducted [...]
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Fast prediction of rain erosion in wind turbine blades using a data-based computational tool
J. Gimenez, S. Idelsohn, E. Oñate

Journal of Hydrodynamics (2024). Vol. 36, pp. 504–518

Abstract
Wind turbines (WTs) face a high risk of failure due to environmental factors like erosion, particularly in high-precipitation areas and offshore scenarios. In this paper we introduce a novel computational tool for the fast prediction of rain erosion damage on WT blades that is useful in operation and maintenance decision making tasks. The approach is as follows: Pseudo-Direct Numerical Simulation (P-DNS) simulations of the droplet-laden flow around the blade section profile are employed to build a high-fidelity data set of impact statistics for potential operating conditions. Using this database as training data, a machine learning-based surrogate model provides the feature of the impact pattern over the 2-D section for given wind and rain conditions. With this information, a fatigue-based model estimates the remaining lifetime and erosion damage for both homogeneous and coating-substrate blade materials. This prediction is done by quantifying the accumulated droplet impact energy and evaluating operative conditions over time periods for which the weather at the installation site is known. In this work, we describe the modules that compose the prediction method, namely the database creation, the training of the surrogate model and their coupling to build the prediction tool. Then, the method is applied to predict the remaining lifetime and erosion damage to the blade sections of a reference WT. To evaluate the reliability of the tool, several site locations (offshore, coastal, and inland), the coating material and the coating thickness of the blade are investigated. In few minutes we are able to estimate erosion after many years of operation. The results are in good agreement with field observations, showing the promise of the new rain erosion prediction approach.
Abstract
Wind turbines (WTs) face a high risk of failure due to environmental factors like erosion, particularly in high-precipitation areas and offshore scenarios. In this paper we [...]
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Multi-scale methods: applications to fluid mechanics problems
S. Idelsohn, J. Gimenez, A. Larreteguy, N. Nigro, F. Sivori, E. Oñate

Mecánica Computacional (2023). Vol. 40 (1), pp. 9-9

Abstract
Multi-scale methods have emerged to facilitate its numerical solution when several simulta- neous scales exist in the same problem, and where all of them exert a significant influence on the solution. The difference in scales may be in the physical properties of the materials, for example density, modulus of elasticity, viscosity or diffusion coefficients, etc. or there may also be a difference in scales in the solution to the problem itself, such as a great difference in the magnitude of the waves or the instabilities involved. Multi-scale methods emerged primarily for the study of composite solids, but have later been generalized to very different applications. In this talk we will apply them to fluid mechanics problems. We will develop two very different types of applications. On the one hand, turbulence problems, where the multi-scale exists due to the great difference in the magnitude of the instabilities existing within a turbulent fluid. In a second application, we will see the problem of fluids that contain particles within them, where their homogeneous study is essential due to the large number of particles that have to be studied.
Abstract
Multi-scale methods have emerged to facilitate its numerical solution when several simulta- neous scales exist in the same problem, and where all of them exert a significant [...]
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Virtual reality for the creation of stories and scenarios for construction safety: social distancing in the COVID-19 pandemic context
F. Rivera, J. Mora, E. Oñate

International Journal of Computational Methods and Experimental Measurements (2023). Vol. 11 (2), pp. 105-114

Abstract
The construction site is a complex and dynamic place. Workers are susceptible to certain risks due to the variability of their worksites, the tasks they perform, and the equipment they use. These aspects make the architecture, engineering, construction, and operation industry (AECO) have high accident rates. These typical processes are added to the growing use of new technologies in the workplace (e.g., drones, robots) that must coexist with human workers, not altering their routines and preserving a safe environment. A key aspect of occupational risk prevention (ORP) is worker training. Traditional training methods are not satisfactory. Given these deficiencies, virtual reality has shown advantages and benefits for training, allowing the development of immersive training experiences that promise to generate more meaningful learning for students. The construction sector needs to reactivate their construction sites after periods of confinement due to the direct implications on the progress of projects and, indeed, the industry's productivity (with the repercussions on costs, time and legal aspects). In this respect, training workers in covid protection measures and designing and analysing changing construction site scenarios to reduce the spread of viruses is crucial to ensure workers' health. This research shows the application and agile development of a training experience for social distancing at construction sites to prevent COVID-19 transmission, based on virtual reality and building information modelling and using serious games as a teaching strategy. Analyses are shown to exemplify the application and potential of the tools.
Abstract
The construction site is a complex and dynamic place. Workers are susceptible to certain risks due to the variability of their worksites, the tasks they perform, and the equipment [...]
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Development of an individual 3D particle reconstruction method for discrete mechanical modeling: Interpolation by Fourier composition
J. Pena, M. Castro, M. Farías, E. Oñate, L. Moreno, C. Recarey

Computer Methods in Applied Mechanics and Engineering (2024). Vol. 420, Art. Num.116705

Abstract
Reconstruction methods for granular materials are an essential step in achieving an accurate geometrical basis in the use of particle methods such as the well-known discrete element method. In this study, a novel continuous analytical method will be proposed to achieve individual 3D reconstructions of granular materials. For this purpose, the 2D Fourier Descriptor theory is used and a generalization of it to the 3D case is obtained, which is quite different from the spherical harmonics theory. Some limitations existing in the original model will be addressed by developing and calibrating a generalized approach that results in a total of four main models. Particles from a study sample are reconstructed, and the models are evaluated based on four generalized error metrics, as well as the presence of some specific limitations detected in the models. Finally, the models are compared using a decision-making method in different decisional scenarios.
Abstract
Reconstruction methods for granular materials are an essential step in achieving an accurate geometrical basis in the use of particle methods such as the well-known discrete [...]
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THE APPLICATION OF HUMAN VISUAL ATTENTION IN MACHINE VISION
M. Al-Azawi

FIBRE4YARDS OA (2024). 1

Abstract
Machine vision is still a challenging topic and attracts many researchers to research in this field. The main difference between machine vision and human vision is that, machine can see images as a set of pixels, while human can used cognitive capabilities in identifying the contents of the image. Attention is one of the important properties of Human Vision System, with which the human can focus only on part of the scene at a time; scenes with more abrupt features shall attract human attention more than other regions. In this paper, we shall simulate the human attention and discuss its application in machine vision and how it will improve the result of the retrieval process and image identification and understanding. Artificial intelligence shall be used in the proposed algorithm to cluster the salient points that were obtained either from eye trackers or from saliency extraction techniques.
Abstract
Machine vision is still a challenging topic and attracts many researchers to research in this field. The main difference between machine vision and human vision is that, machine [...]
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Robustez y componente gigante de la red aeroportuaria de la República Mexicana mediante un análisis en Teoría de Grafos
O. Rosas, L. Olivares-Quiroz

SMCCA (2024). 7

Abstract
La robustez de un grafo es un parámetro que cuantifica la vulnerabilidad de una red bajo ataque en alguno de sus nodos. La robustez se define como la fracción de la componente gigante después de que se eliminan ciertos nodos ya sea de forma aleatoria o bien de forma específica. Usando estas dos últimas definiciones y un script de programación en Python y NetworkX analizamos la dinámica de la componente conectada principal de la red de tráfico aéreo de la República Mexicana cuando se realizan ataques aleatorios y dirigidos en sus nodos. Asimismo, y a manera de comparación, calcularemos la fracción crítica de nodos eliminados en función de la densidad de la red para diferentes redes aleatorias usando el modelo de Gilbert y la red de tráfico aéreo de la República Mexicana con el fin de decidir si ésta última es o no es vulnerable a dichos ataques. Los resultados obtenidos muestran el grado de vulnerabilidad de la red de tráfico aéreo en la República Mexicana.
Abstract
La robustez de un grafo es un parámetro que cuantifica la vulnerabilidad de una red bajo ataque en alguno de sus nodos. La robustez se define como la fracción [...]
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Research on similarity law of nonlinear shock response of ship plate frame structure under underwater explosion
J. Wang, D. Shi, X. Yao, Z. Wang

WCCM2024.

Abstract
The anti-explosion ability of ship grillage structure is an important index to evaluate the vitality of ships. Its model test is a low-cost and effective method to evaluate the vitality of ships and guide the design of ship anti impact structures. In view of the nonlinear and nonstationary process of underwater explosion damage to ship grillage, this paper breaks through the nonlinear effect of transient explosion impact that is not considered in the traditional scale model design, focuses on the one-dimensional nonlinear impact response of ship grillage structure, and carries out the characterization study of the similarity between model experiments and real ships. Considering that the vertical motion of the prototype and the model grillage structure in the model test obey the random walking model, the vertical impact response of the deck grillage is characterized as one-dimensional nonlinear non-stationary Brownian motion, which is described by Hurst index. Based on the classical similarity law, the similarity transformation relationship between the range R and the mean square deviation S is derived, and the Hurst index of the model and the prototype meets the equal relationship; Take a section of grillage structure on a real ship and conduct prototype, 1/2, 1/3, 1/4 and 1/5 one-dimensional nonlinear explosion impact scale simulation tests respectively. The numerical response results show obvious nonlinear characteristics, and the Hurst index of displacement, velocity and acceleration response of the model within the pulse width range is less than 5% compared with the prototype. According to the scale invariance of fractional Brownian motion, the similarity conversion relationship of multiple parameters (displacement, velocity, acceleration and mean square response) is obtained. With the mean square response as the characteristic parameter, the response value of the prototype is converted through this relationship, and compared with the model simulation results, the multi parameter response error under each scale ratio is less than 20%. It provides theoretical and technical support for conducting similar experiments on nonlinear response of underwater explosion shock of ships
Abstract
The anti-explosion ability of ship grillage structure is an important index to evaluate the vitality of ships. Its model test is a low-cost and effective method to evaluate [...]
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Energía nuclear: una alternativa válida para las inversiones sostenibles
M. Carrasquer

Abstracts_4rceec (2024). 218

Abstract
Ante el creciente desafío de mitigar el cambio climático y la necesidad de una transición hacia una economía de bajas emisiones de carbono, la energía nuclear resurge como una opción viable para satisfacer la demanda energética global. Este estudio evalúa la viabilidad de la energía nuclear como inversión sostenible. Aunque la energía nuclear ha sido históricamente polémica debido a los riesgos asociados y la gestión de residuos radiactivos, su capacidad para generar electricidad con bajas emisiones de gases de efecto invernadero y de forma estable, la posiciona como un componente crucial en la transición energética. El estudio comienza abordando los orígenes de la energía nuclear, desmitificando algunas creencias populares sobre su seguridad y destacando la evolución de la tecnología nuclear a lo largo del tiempo. Se exploran aspectos fundamentales como la construcción y desmantelamiento de plantas nucleares, así como la gestión de residuos radiactivos, un tema esencial en su aceptación pública. Todo, absolutamente todo en la naturaleza es radiactivo. ¿Eras consciente de ello? Cualquier objeto de la vida cotidiana contiene isótopos radiactivos que emiten tipos y niveles diferentes de radiación. Porque la radiación es un fenómeno natural sin el cual, la vida en la Tierra no sería posible. Este estudio no aborda aspectos técnicos sobre el funcionamiento de la energía nuclear, sino que se enfoca en su viabilidad como una opción de inversión sostenible. Se profundiza en el papel de la energía nuclear en la transición energética, analizando cómo puede contribuir a la reducción de emisiones y garantizar un suministro energético confiable. También se revisa la situación actual de los países líderes en tecnología nuclear, junto con su inclusión en la Taxonomía de la UE y su impacto en los Objetivos de Desarrollo Sostenibles (ODS). Este análisis examina como acceder desde los mercados de capitales en la contribución de la energía nuclear. Utilizando datos de proveedores externos de referencia en métricas sostenibles, la conformidad de compañías cotizadas con los requisitos clave de estándares internacionales y otros aspectos relevantes. Los resultados sugieren que, bajo condiciones específicas, la energía nuclear puede ser considerada sostenible, siempre que se cumplan rigurosos requisitos. En definitiva, el objetivo del estudio evalúa cómo la energía nuclear puede integrarse en carteras de inversión sostenible y cómo la evolución del mercado del uranio y las tecnologías nucleares ofrecen perspectivas para los inversores, destacando su potencial para contribuir a los objetivos del Acuerdo de París y su relevancia en la diversificación de la matriz energética. La postura adoptada en este estudio es favorable para que los mercados de capitales potencien la financiación de proyectos nucleares, siempre que se cumplan los más altos estándares de seguridad y sostenibilidad.
Abstract
Ante el creciente desafío de mitigar el cambio climático y la necesidad de una transición hacia una economía de bajas emisiones de carbono, la [...]
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CHAPTER 23: REVALUATION OF RECYCLED REINFORCEMENT FIBERS THROUGH TEXTILE TECHNOLOGIES
I. Martínez, J. Bernabeu

libro-blanco-materiales-compuestos (2024). 34

Abstract
This chapter addresses the environmental and energy challenges posed by the increasing production of composite materials, particularly those reinforced with carbon and glass fibres. Current recycling technologies focused on fibre recovery, such as thermal and chemical methods, now enable the production of fibres suitable for reintegration into the value chain. The chapter details adapted textile technologies for processing these recycled fibres, covering methods from non-woven fabric production to the newest manufacturing technology of yarns and unidirectional tapes. Technologies such as carding and yarn formation are analyzed, highlighting the need for hybridization with virgin materials to enhance the mechanical properties of the final products. While current advances do not yet match the performance of virgin materials, ongoing research continues to optimize these processes, paving the way for the industrialization of more sustainable composites, with applications ranging from lightweight structures to sectors with higher mechanical requirements.
Abstract
This chapter addresses the environmental and energy challenges posed by the increasing production of composite materials, particularly those reinforced with carbon and glass [...]
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CHAPTER 25: CONCLUSIONS
libro-blanco-materiales-compuestos (2024). 33
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A mathematical model of the formation of urine
F. Domínguez Pérez, J. LOPEZ

SMCCA (2024). 4

Abstract
In this work, a mathematical model of renal hemodynamics involved in urine production is studied. The model is formed by three sub-models: one corresponds to the glomerular filtration stage, which gives input to the blood that is processed in the kidney; another one is the corresponding to the renal autoregulation process which defines the blood flow that must enter the kidney, to maintain its correct functioning, even in the face of blood pressure variations; and the last sub-model corresponding to the reabsorption and secretion stages, the former corresponds to the process by which the kidneys recover useful substances from the glomerular filtrate and return them to the blood and in the latter the kidneys eliminate unwanted substances from the blood into the peritubular capillaries.
Abstract
In this work, a mathematical model of renal hemodynamics involved in urine production is studied. The model is formed by three sub-models: one corresponds to the glomerular [...]
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Bayesian Estimation of the Basic Reproductive Number in a Chikungunya Outbreak in Acapulco, Guerrero
M. Vázquez-Peña, C. Vargas-De-León, R. Martínez-Fonseca, J. Velázquez-Castro

SMCCA (2024). 5

Abstract
Chikungunya is a vector-borne viral disease caused by the mosquitoes Aedes aegypti and Aedes albopictus. There is no specific medical treatment or available vaccine. This work presents a host-vector model that considers two age structures: chronological age and asymptomatic infection age. This model accounts for variability in the relapse period and susceptibility to the chikungunya virus. From this system of integro-differential equations, a particular case is derived in the form of ordinary differential equations (ODEs). The objective of this study is to estimate the basic reproductive number R0 of the ODE model for a chikungunya outbreak that occurred in 2015 in Acapulco, Mexico. A Bayesian approach using Hamiltonian Monte Carlo methods is applied to estimate the parameters of the ODE model and subsequently estimate R0. We estimate that R0 is 2.61, with a 95% credibility interval of (1.66, 3.80), which is consistent with other reports in the literature.
Abstract
Chikungunya is a vector-borne viral disease caused by the mosquitoes Aedes aegypti and Aedes albopictus. There is no specific medical treatment or available [...]
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Three Pillars for Digital Twins: Experiments, Simulation, and Artiﬁcial Intelligence
A. Hashemi, P. Ryzhakov, A. Ares

International workshop on Inkjet Technology and Beyond: Experiments, CFD, and Artificial Intelligence (2024). 1

Abstract
This presentation aims to highlight the synergy between experimental studies, Computational Fluid Dynamics (CFD) simulations, and Artificial Intelligence (AI) in developing high-fidelity, real-time digital twins that optimize and enhance the precision and performance of microfluidic systems. Digital twins are virtual replicas of physical systems that enable improved decision-making and performance optimization. These systems are particularly useful in complex scenarios where physical testing is costly or impractical. Digital twins allow for the exploration of ‘what-if’ scenarios and the prediction of outcomes under varying conditions, thus offering a comprehensive tool for modern engineering challenges. The impacts of effective digital twins are substantial, ranging from cost reduction and quality improvement to faster time-to-market, product differentiation, and enhanced product reliability.
Abstract
This presentation aims to highlight the synergy between experimental studies, Computational Fluid Dynamics (CFD) simulations, and Artificial Intelligence (AI) in developing [...]
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MIGRANTES CLIMÁTICOS EN BOLIVIA: UNA EVALUACIÓN SOBRE LAS POLÍTICAS PÚBLICAS DE PROTECCIÓN A LA MADRE TIERRA
A. Cabello Ayzama

Conferencia Innova 2024

Abstract
El presente documento presenta un análisis sobre la crisis climática en Bolivia, evaluando las políticas públicas existentes y su impacto en los migrantes climáticos. Mediante una revisión de literatura detallada, se identificaron desafíos comunes y buenas prácticas en la respuesta política. La investigación se centró en la revisión de la Política Plurinacional de Cambio Climático y casos específicos de migración interna, como el caso del Lago Poopó, para comprender mejor los efectos del cambio climático en las comunidades bolivianas. Se concluye que, aunque Bolivia ha reconocido la importancia del cambio climático a nivel constitucional, existe una brecha significativa entre la teoría y la práctica en la protección de los derechos de los afectados por este fenómeno. Se destaca la necesidad de una participación más activa del Estado y medidas concretas para abordar la crisis climática y proteger a las comunidades vulnerables.
Abstract
El presente documento presenta un análisis sobre la crisis climática en Bolivia, evaluando las políticas públicas existentes y su impacto en los [...]
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CHAPTER 20: FAST WARMING AND LOW ENERGY CONSUMPTION
. , L. AEMAC

libro-blanco-materiales-compuestos (2024). 37

Abstract
Muchos de los procesos de fabricación de estructuras de material compuesto se basan en grandes y costosasinstalaciones que originan procesos lentos, caros, y poco eficientes energéticamente. El preformado de tejidos de fibra seca, por ejemplo, se realiza en grandes instalaciones de hot drape forming, donde las fuentes convencionales de calentamiento basadas en lámparas infrarrojas son poco eficaces, ya que gran parte del calor suministrado se transfiere a los pesados moldes de aluminio en los que se lleva a cabo el proceso de preformado. En el contexto actual en el que es fundamental reducir la huella de carbono de cada componente, es fundamental reducir la energía necesaria en los procesos de producción y al mismo tiempo conseguir tiempos de ciclo competitivos. En este contexto, Tecnalia lleva años trabajando en la tecnología del calentamiento resistivo directo con el fin de acelerar y optimizar los procesos de fabricación de material compuesto. La aplicación directa de una corriente sobre el material de carbono a procesar supone la ventaja de evitar el calentamiento y enfriamiento de los moldes u otros utillajes adyacentes, obteniendo los resultados de forma mucho más rápida y eficaz que con los métodos utilizados hasta ahora. En el caso, por ejemplo, del proceso de preformado de tejidos de carbono, aplicar el calentamiento solo a la preforma permite reducir los tiempos de ciclo y el consumo energético más de un 60% y 80% respectivamente. Esto supone reducir el coste del proceso relacionado con un menor consumo energético y un menor tiempo de ciclo. La calidad de las preformas obtenidas mediante el preformado resistivo es similar a la obtenida mediante la tecnología convencional hot drape forming y, además, es un proceso repetitivo que se ha validado en entorno de fabricación industrial. En el artículo se indica también que esta tecnología de calentamiento resistivo directo no solo es aplicable en procesos de preformado de carbono, sino que también podría emplearse potencialmente en otros procesos de fabricación de componentes de material compuesto.
Abstract
Muchos de los procesos de fabricación de estructuras de material compuesto se basan en grandes y costosasinstalaciones que originan procesos lentos, caros, y poco eficientes [...]
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Acute or a Cute Robot? The Effect of Angularity on Medical Service Robot Perception
E. Yadgarov

Collection of Articles on Psychology (2024). 2

Abstract
Despite the importance of medical care, one in three Americans avoid doctor visits (Cleveland Clinic Medical Professional, 2021). Considering our modernizing world, applying robotics to healthcare, particularly with Medical Service Robots (MSRs), yields the potential to improve patient engagement and overall care (“Medical robots,” n.d.). Recognizing the impact of design on user perceptions, the purpose of this study was to manipulate the angularity and curvature of MSR designs to reduce perceived threat and increase warmth and trust among patients. Participants (N=230) were randomly assigned to one of three conditions: curved MSR design, angular design, or a no-image control group. After viewing the stimulus, participants answered Likert-type scales that measured their perception of them. ANOVA tests revealed that perceived trust was unaffected by angularity, while perceived warmth approached significance (p = .06). Significant effects were found for preference (p = .02) and perceived threat (p = .04), with the curved MSR design being most preferred and the angular version perceived as most threatening. Additionally, gender was found to have a significant main effect for preference (p < .01), warmth (p = .04), and trust (p = .04) as males rated the robots higher than females. These findings can be used to create MSR designs that are most positively perceived, thus optimizing their ability to improve patient care.
Abstract
Despite the importance of medical care, one in three Americans avoid doctor visits (Cleveland Clinic Medical Professional, 2021). Considering our modernizing world, applying [...]
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Innovation in Epilepsy Management in South Asia: Design and Development of a Wearable Seizure Detection Device
A. Waqar, A. Waqar

J. of Dawn. R. (2024). Vol. 6, 9

Abstract
This study introduces the Epilet Band, an innovative wristwatch-like device employing machine learning algorithms to detect Convulsive Epileptic Seizures (CES) in real-time. Distinguished by its use of Federated Machine Learning (FML), it ensures maximum data privacy and minimal data transfer. The Epilet band uses the DAP (detection, avoidance and prevention) method and incorporates a carefully selected array of sensors– accelerometer, gyroscope, temperature sensor, light intensity sensor and a digital microphone– all integrated into the Arduino Nano 33 BLE Sense. This study developed a seizure generator that replicates the movement patterns observed during epileptic seizures. Utilizing the Edge Impulse training platform, a machine learning model is trained to recognize these seizures, continually refining its accuracy through retraining and remodeling processes. The Epilet Band works by differentiating epileptic seizures from day-to-day activities by detecting muscle movement patterns produced by the two actions. Moreover, the Epilet Band actively detects ambient temperature, humidity, noise levels and light intensity (for example flashing lights over a period of 5 seconds) and alerts the user’s caretaker in case these conditions align with those which trigger epileptic seizures, with a message that an attack could be triggered. Research findings demonstrate the efficacy of the proposed Epilet band in detecting uncontrollable convulsive seizures timely. The machine learning model allows for improved accuracy of the detection algorithm as the number of trials and sample size increase with time. Being alerted of a potential seizures or triggers affords caretakers the opportunity to act fast to reduce fatalities or unfortunate accidents caused by a sudden onset of seizure. This exhaustive study underscores the innovation and scientific diligence captured by the Epilet Band, illustrating a future where epilepsy management is significantly empowered through technology trained by existing data, offering new horizons for individuals afflicted with this condition.
Abstract
This study introduces the Epilet Band, an innovative wristwatch-like device employing machine learning algorithms to detect Convulsive Epileptic Seizures (CES) in real-time. [...]
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La necessitat d’una gestió sostenible del tipus de canvi a les empreses
M. FUSTER, G. Congrés2025

Abstracts_4rceec (2024). 221
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El cuadro comparativo entre constitucionalismo multinivel, transconstitucionalismo e interconstitucionalismo: un equilibrio de conceptos y bases explicativas
A. Cabello Ayzama

Revista Pensamiento Jurídico (2022).

Abstract
El presente artículo busca revisar las principales construcciones teóricas sobre constitucionalismo y los conceptos de constitucionalismo trans-, inter- y multinivel. La problematización central del artículo es cómo describir los intentos teóricos de explicar los fenómenos de trans-, inter- o multiconstitucionalismo. Es una investigación que tiene el postulado descriptivo inicial de varias matrices teóricas, con breves incursiones analíticas sobre estas mismas construcciones, y finaliza con la organización del listado de clasificaciones teóricas. El material utilizado en la redacción del texto es material bibliográfico sobre teoría constitucional, derecho constitucional y, de manera complementaria, teoría política y derecho internacional. Los resultados del trabajo son clasificaciones y ordenamiento de los catálogos teóricos que presentan los elementos de similitud y disimilitud entre los conceptos en mención.
Abstract
El presente artículo busca revisar las principales construcciones teóricas sobre constitucionalismo y los conceptos de constitucionalismo trans-, inter- y multinivel. [...]
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Una nova estratègia d’internacionalització per al segon quart del segle XXI
D. Guri, J. Serret

Abstracts_4rceec (2024). 217

Abstract
Entre els trets més significatius que caracteritzen l’economia catalana està, sens dubte, la seva obertura exterior. Milers d’empreses -la majoria pimes- han incorporat, poc o molt, la presència en els mercats internacionals com a element indefugible de la seva estratègia empresarial. Administracions i organitzacions empresarials, en paral·lel, han estructurat programes i serveis de suport tendents a reforçar aquest procés, generant-se un ecosistema d’internacionalització amb una multiplicitat d’actors que porten a la pràctica la seva visió, les seves receptes, no sempre del tot alineades, amb l’objectiu que l’empresa les tradueixi en el seu compte de resultats. En un escenari com l’actual, on un conjunt de megatendències estan incidint de ple en el procés d’internacionalització, tendències que no es poden afrontar de manera lineal, cal una visió holística, sistèmica, amb noves maneres de plantejar l’estratègia. Poden les empreses seguir actuant com quan s’anunciava l’adveniment d’un món pla, de la fi de la història de Fukuyama, o han de fer front a les conseqüències d’un món multipolar en crisi permanent? No es pot parlar de digitalització, d’intel·ligència artificial, ni d’innovació sense considerar els mercats exteriors, que són motors i destinataris d’aquests processos. Avui, més que mai, els valors socials i ambientals estan qüestionant els fonaments del nostre sistema econòmic i les regulacions associades estan afegint complexitat a la internacionalització. Una empresa no pot obviar la sostenibilitat si vol ser capdavantera. Si donem resposta a aquestes i d’altres variables, no serà inevitable que el sistema productiu català es plantegi una nova aproximació per afrontar la internacionalització del segon quart del segle XXI? Es proposaran els elements clau que haurien de caracteritzar una nova estratègia guanyadora de internacionalització del teixit productiu català en aquest nou entorn.
Abstract
Entre els trets més significatius que caracteritzen l’economia catalana està, sens dubte, la seva obertura exterior. Milers d’empreses -la [...]
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ANNEX 1: COMPANIES ASSOCIATED WITH AEMAC
libro-blanco-materiales-compuestos (2024). 32
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The Role of Proteins in Glial Cell Autophagy and Apoptosis in the Dentate Gyrus
W. Ahmuty

J. of Dawn. R. (2024). Vol. 6, 10

Abstract
The dentate gyrus is a unique part of the brain because it is known for housing neurogenesis in the adult brain, a process which normally stops early in development. This makes the dentate gyrus an area of great interest, especially in combating neurodegenerative diseases. This area, as well as the entire nervous system, is composed of both neurons, which send and receive signals, and glial cells, which are responsible for supporting neurons. Glial cells including astrocytes, oligodendrocytes, and ependymal cells are present in both the central nervous system and peripheral nervous system, while Schwann Cells are present only in the peripheral nervous system, and microglia are present only in the central nervous system. Apoptosis and autophagy are both processes which degrade and recycle materials. Autophagy degrades materials inside the cell, such as organelles and proteins, and uses lysosomes to carry out the process. Apoptosis consists of degrading old or damaged cells, and is known as programmed cell death. Many proteins affect these processes including Beclin-1, UC3, p62, and the BCL-2 family of proteins. Some studies have used machine learning algorithms in conjunction with simulation and statistical software to study these proteins and the processes they are involved in. Several areas of research remain unfilled, especially in the area of glial cells and the proteins involved in autophagy and apoptosis, as not many machine learning studies have examined this.
Abstract
The dentate gyrus is a unique part of the brain because it is known for housing neurogenesis in the adult brain, a process which normally stops early in development. [...]
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The role of Beclin1 in astrocyte autophagy in the dentate gyrus
B. Ahmuty, W. Ahmuty

Collection of Articles on Neuroscience (2024). 1

Abstract
The dentate gyrus is a unique part of the brain because it is known for housing neurogenesis in the adult brain, a process which normally stops early in development. This makes the dentate gyrus an area of great interest, especially in combating neurodegenerative diseases. This area, as well as the entire nervous system, is composed of both neurons, which send and receive signals, and glial cells, which are responsible for supporting neurons. Glial cells including astrocytes, oligodendrocytes, and ependymal cells are present in both the central nervous system and peripheral nervous system, while Schwann Cells are present only in the peripheral nervous system, and microglia are present only in the central nervous system. Apoptosis and autophagy are both processes which degrade and recycle materials. Autophagy degrades materials inside the cell, such as organelles and proteins, and uses lysosomes to carry out the process. Apoptosis consists of degrading old or damaged cells, and is known as programmed cell death. Many proteins affect these processes including Beclin-1, UC3, p62, and the BCL-2 family of proteins. Some studies have used machine learning algorithms in conjunction with simulation and statistical software to study these proteins and the processes they are involved in. Several areas of research remain unfilled, especially in the area of glial cells and the proteins involved in autophagy and apoptosis, as not many machine learning studies have examined this.
Abstract
The dentate gyrus is a unique part of the brain because it is known for housing neurogenesis in the adult brain, a process which normally stops early in development. This [...]
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ANNEX 2: LIST OF PROJECTS RELATING TO SUSTAINABILITY
H. ABRIL

libro-blanco-materiales-compuestos (2024). 31
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CHAPTER 19: MATERIALS COMPOSED OF NATURAL FIBERS
A. Morales, A. López, A. Güemes

libro-blanco-materiales-compuestos (2024). 38

Abstract
This technical report addresses the study of composite materials with natural fibers as reinforcement. The properties, applications and manufacturing processes of these materials are explored, highlighting their relevance in various industries. The environmental and sustainable benefits associated with the use of natural fibers instead of traditional materials are analyzed, as well as the current issues to overcome.
Abstract
This technical report addresses the study of composite materials with natural fibers as reinforcement. The properties, applications and manufacturing processes of these materials [...]
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CHAPTER 14: REUSE OF POLYMERIZED COMPOSITE MATERIALS
J. Fernández de la Puente Calvo, J. Jhala, R. Planche

libro-blanco-materiales-compuestos (2024). 44

Abstract
Spain, holding a prominent position in Europe's composites industry and notably in aviation composites, faces significant waste management challenges within its 500-strong composite company sector. As it shifts towards the Circular Economy to enhance competitiveness and resource efficiency, Spain adheres to the EU's waste hierarchy, emphasizing the critical need for waste minimization and the reuse of materials. This transition is particularly vital given the environmental impact of disposing of polymer-matrix composites, especially cured composites, with Europe generating roughly 400,000 tonnes of thermoset composite waste annually, a substantial portion of which is from Spain. This study delves into the reuse and repurposing of polymer composites, promoting their integration within the Circular Economy to preserve material integrity and value. It showcases innovative repurposing projects in Spain and across Europe, such as transforming wind turbine blades into materials for construction, which demonstrates the feasibility of extending these materials' lifecycles. These efforts align with sustainability goals aimed at waste reduction and resource conservation. However, challenges persist, including matching waste volume and condition with market demands and scaling these practices effectively. The concept of structural re-use, turning cured composite waste into high-value, reusable products, highlights the potential of merging reuse and recycling strategies. Innovative approaches to reuse not only mitigate sustainability challenges but also foster economically viable solutions, marking a significant stride towards sustainable and efficient resource utilization in the composites sector.
Abstract
Spain, holding a prominent position in Europe's composites industry and notably in aviation composites, faces significant waste management challenges within its 500-strong [...]
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CHAPTER 21: REUSABLE AUXILIARY MATERIALS. ALTERNATIVE VACUUM BAGS
M. Rodríguez

libro-blanco-materiales-compuestos (2024). 36

Abstract
Auxiliary materials are essential elements for polymer composites manufacturing. Each of these elements performs a specific function and requires partícular characteristics depending on the process parameters. They are generally single-use materials (consumables) and thermoplastics nature, so they could be recovered and recycled. However, due to the manufacturing process of composite parts, this recycling becomes complex due to contamination by resin and fibers and the heterogeneity of the different auxiliary materials. Because of this, one of the alternatives to reduce the consume of these elements and minimize their environmental impact is to use of reusable auxiliary materials. Currently, there are commercial solutions based on silicones. This alternative must be evaluated for each case, considering parameters such as the number of parts to be manufactured or their size and geometry.
Abstract
Auxiliary materials are essential elements for polymer composites manufacturing. Each of these elements performs a specific function and requires partícular characteristics [...]
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CHAPTER 22: DESIGN CONCEPTS BASED ON LOW CARBON FOOTPRINT CONSIDERATIONS AND METHODOLOGIES, EASE OF SEGREGATION AND RECOVERY.
B. Lekube

libro-blanco-materiales-compuestos (2024). 35

Abstract
In the current context of transitioning towards a circular economy and the digital age, the design of products based on composite materials requires a rethinking of decision-making processes. It is necessary to incorporate methodologies that include sustainability concepts, from selecting materials that can be revalorized to designing a product so that segregation at the end of its useful life is as simple as possible, always ensuring the technical, functional, and safety requirements of the products. This presents a complex scenario that will be elaborated on in the following sections:
Abstract
In the current context of transitioning towards a circular economy and the digital age, the design of products based on composite materials requires a rethinking of decision-making [...]
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CHAPTER 18: REACTIVE THERMOPLASTIC RESINS
. C.Elizetxea, . S.García-Arrieta, A. Calle, M. Manchado, R. Márquez, A. Bethencourt

libro-blanco-materiales-compuestos (2024). 39

Abstract
One of the main challenges currently faced by the composite materials sector is to ensure its sustainability, both at the level of the raw materials used, the production means necessary for its transformation, as well as its management and treatment. at the end of its useful life. Especially critical is the situation of thermostable composite materials, widely used in structural applications due to their excellent performance/weight ratio. There are different fields of research, oriented towards the search for more sustainable alternatives for these matrices so that these high mechanical performances continue to be guaranteed and that they can be transformed by conventional manufacturing processes. Reactive thermoplastic resins are a sustainable alternative for the manufacture of recyclable, weldable and processable structural composite components by conventional manufacturing technologies (Infusion, RTM. Pultrusion, Fillament Winding)
Abstract
One of the main challenges currently faced by the composite materials sector is to ensure its sustainability, both at the level of the raw materials used, the production means [...]
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CHAPTER 17: VITRIMERS
N. Markaide, A. Ruiz

libro-blanco-materiales-compuestos (2024). 41

Abstract
The development of recyclable plastics is a key focus of research in the current world due to its environmental issues and concerns about non-renewability. Recently, vitrimeric materials have garnered significant attention as an exciting class of renewable plastics due to their potential to exhibit strength, durability, and chemical resistance approaching that of traditional thermosetting plastics, while also demonstrating recyclability at the end of their lifespan. This is attributed to their chemical structure, as vitrimers possess dynamic covalent crosslinking, providing them with stability while being reprocessable. This review summarizes the latest advancements and prospects in the development of vitrimeric materials. Special emphasis is placed on vitrimer design strategies that pave the way for the development of next-generation circular materials. The emerging applications of vitrimers are also discussed in terms of their properties, including self-repair, malleability, processability, and multiple shape memory.
Abstract
The development of recyclable plastics is a key focus of research in the current world due to its environmental issues and concerns about non-renewability. Recently, vitrimeric [...]
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CHAPTER 16: BIO-MONOMERS AND THERMOSTABLE BIO-RESINS
S. Prolongo, A. Suárez

libro-blanco-materiales-compuestos (2024). 42

Abstract
Thermosetting resins, especially epoxy resins, have historically been based on petroleum-derived monomers, posing problems of toxicity, high costs, and dependence on non-renewable resources. This chapter presents the use of natural plant sources to develop more sustainable resin precursors. The synthesis of bio-epoxy monomers from vegetable oils, polysaccharides, lignin, polyphenols, and natural resins is currently the subject of interest in several research projects and scientific papers, in some cases reaching the level of product commercialization. Vegetable oils, such as linseed and soybean, and the transformation of saccharides into epoxy monomers are examples of explored options. Naturally occurring epoxy monomers derived from polyphenols from various plant sources can also be found, although their epoxidation requires the use of toxic compounds such as epichlorohydrin. Several natural sources, such as natural rubber, resin acids, and lignin are examined as alternatives to synthesize epoxy resins of natural origin. Leutelin, recently identified in fruits and medicinal herbs, is highlighted as a promising compound to produce bioepoxy monomers. Although initially the research focused mostly on the development of monomers of natural origin, research also extends to hardeners of natural origin, highlighting the synthesis of amines from vanillin and curing agents based on phenalkamines. The development of hardeners with reversible bonds, such as lignin imines, is also being explored, and the catalytic effect of hemp fibers in the curing of epoxy resins is highlighted. The combination with traditional monomers or the development of recyclable resins and vitrimers with reversible bonds are current fields of interest for the development of these resins, especially in the context of their competitors of petrochemical origin.
Abstract
Thermosetting resins, especially epoxy resins, have historically been based on petroleum-derived monomers, posing problems of toxicity, high costs, and dependence on non-renewable [...]
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CHAPTER 15: REUSE OF FIBERS AND RESINS IN STRUCTURAL ELEMENTS. PROPOSALS FOR USE IN DIFFERENT INDUSTRIES: PRELIMINARY PROPOSALS FOR USE
R. Vera

libro-blanco-materiales-compuestos (2024). 43

Abstract
One of the main problems of composite recyclability, is to find applications with a positive business case and technically viable. In order to determine possibilities, it is necessary, first, to analyze mechanical properties of materials as well as today available manufacturing processes with this type of products.
Abstract
One of the main problems of composite recyclability, is to find applications with a positive business case and technically viable. In order to determine possibilities, it [...]
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CHAPTER 13: WASTE MANAGEMENT AND REUSE TECHNOLOGIES OF NON-POLYMERIZED COMPOSITE MATERIALS
N. Martín, Á. Casanova

libro-blanco-materiales-compuestos (2024). 45

Abstract
This chapter addresses two relevant challenges to enforce in a manufacturing plant where carbon fiber prepreg is used as raw material for the manufacture of aeronautical parts. The first challenge is the segregation of fresh production waste, where the resin is fresh and has a big potential for being used as material for other applications. This chapter described a proposal for the collection of this highly valuable material in a pilot plant where aircraft stabilizers are manufactured. This second challenge addresses solutions for the reprocessing of waste material discarded during the manufacturing of carbon parts. Hereafter is described the preparation of new materials or by-products, which can be reincorporated into the production system of other composite material parts.
Abstract
This chapter addresses two relevant challenges to enforce in a manufacturing plant where carbon fiber prepreg is used as raw material for the manufacture of aeronautical parts. [...]
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CHAPTER 10: MECHANICAL RECYCLING OF COMPOSITE MATERIALS
S. Prolongo, A. Suárez

libro-blanco-materiales-compuestos (2024). 48

Abstract
The mechanical recycling of long-fiber composite materials is presented as an alternative of greater technological simplicity as well as low energy consumption, emission of pollutants and use of solvents, which places it in an advantageous position from the point of view of environmental sustainability. However, the products obtained are short-fibered, which reduces their mechanical reinforcement capacity, and have been used mainly as fillers for cementitious, asphalt and thermoplastic matrices. The technologies used to reduce the size of the initial pieces substantially influence the characteristics of the final product obtained, especially if they are to be used for functional purposes in terms of electrical or thermal properties. In addition, the fibers obtained have a proportion of resin from the initial composite material, so the subsequent treatment processes of these fibers, both physical and chemical, can affect the amount of final resin present in the product, its agglomeration or its surface characteristics. The current challenges for these products is to find processes that allow a better quality and greater uniformity of the final properties of the short fiber, so that the products obtained present a greater added value, which allows them to compete with other current discontinuous reinforcements.
Abstract
The mechanical recycling of long-fiber composite materials is presented as an alternative of greater technological simplicity as well as low energy consumption, emission of [...]
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CHAPTER 12: WASTE REDUCTION IN PRODUCTION AND REUSE OF MATERIALS
L. Coronado, I. Raboso

libro-blanco-materiales-compuestos (2024). 46

Abstract
The efforts to reduce, reuse and recycle scrap derived from manufacturing processes with composite materials are significantly increasing in all those sectors making use of such materials in their production systems. The rising commitment with the environmental cause and the everyday stricter regulation in terms of waste management has led to launching new initiatives to minimize the environmental impact of composite materials and derived components manufacturing. Therefore, the aim of this chapter is to provide several examples of optimization initiatives in the use of composite materials and, consequently, the reduction and reuse of waste in production environments in the aeronautical sector, having Airbus as a reference where, according to the available pre-pandemic data, 61% of the scrap corresponds to uncured material whereas 39% refers to cured waste.
Abstract
The efforts to reduce, reuse and recycle scrap derived from manufacturing processes with composite materials are significantly increasing in all those sectors making use of [...]
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CAPÍTULO 11: TECNOLOGÍAS DESTINADAS A LA REUTILIZACIÓN DE FIBRAS CORTAS DE VIDRIO Y CARBONO RECICLADAS
J. Navarro, L. Quilez", B. Bas

libro-blanco-materiales-compuestos (2024). 47

Abstract
En este capítulo se describen las diferentes estrategias de reutilización que se pueden llevar a cabo con los materiales compuestos con matrices poliméricas una vez pasados por los centros de reciclaje actualmente disponibles a escala industrial. El trabajo describe cómo, dependiendo de la naturaleza tanto de las matrices como de las fibras de refuerzo, la reutilización de este tipo de fibras debe estar dirigida hacía un tipo de procesos u otros y cómo, mediante la variación de las tecnologías, es posible dar lugar a productos con una mayor o menor orientación de las fibras. De la misma manera, el capítulo analiza algunos de los procesos de fabricación de materiales compuestos, que pueden afectar a la longitud de las fibras y por lo tanto modificar las propiedades del material final. De esta forma, se describen las diferentes tecnologías actualmente disponibles y en proceso de desarrollo en España para poder dar una nueva vida a las fibras de carbono y de vidrio, orientadas a retener la mayor parte de su valor añadido y propiedades, como son: reutilización en materiales compuestos termoestables, reutilización como refuerzo en materiales compuestos termoplásticos, reprocesado de la fibra (estructuras de fibra tejidas o no tejidas), reciclado de fibras que todavía estén embebidas, reciclajes específicos según la naturaleza de la fibra. A lo largo del texto se van recogiendo algunos de los proyectos liderados por entidades españolas con mayor relevancia en el desarrollo de las diferentes tecnologías y, además, al final del mismo se remarcan esos mismos proyectos y otros más en los que se destaca el trabajo realizado por centros, universidades y empresas españolas en el campo de la reutilización y reciclaje de fibras de carbono y de vidrio.
Abstract
En este capítulo se describen las diferentes estrategias de reutilización que se pueden llevar a cabo con los materiales compuestos con matrices poliméricas [...]
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Spatiotemporal Distribution of Phytoplankton in Long Island’s Coastal Waters Revealed by Remote Sensing
C. Zhang, N. Spinelli

J. of Dawn. R. (2024). Vol. 6, 8

Abstract
Phytoplankton play a major role in marine ecosystem health. They form the base of aquatic food webs, but under conditions of nutrient loading and high stratification, they can develop into harmful algal blooms that produce toxins harmful to humans and wildlife. Ongoing phytoplankton blooms have been observed in Long Island’s (LI) coastal waters for the past half-century, but there is a lack of a comprehensive view of phytoplankton spatiotemporal distribution and their driving factors due to the analysis of specific sampling sites, species, and years. Thus, this study obtained 20 years of chlorophyll-a, climate, and nutrient remote sensing and in situ data from the ERDDAP data server and the CTDEEP Long Island Sound Water Monitoring Program to establish phytoplankton phenology using the threshold criterion and cumulative sum of anomalies methods and to investigate regional differences, influencing factors, and interannual trends using correlation and linear trend analysis. The phenology of summer-autumn blooms in Long Island Sound (LIS) was associated with high sea surface temperatures (r = -0.46, p < 0.01). In contrast, winter-spring blooms were most strongly correlated with low salinity (r = -0.52, p < 0.01), indicating P-rich Connecticut river discharges as the dominant nutrient source. However, phytoplankton in LI’s southern shores lack access to river outlets, so phytoplankton production was driven by deep winter mixings from low SST that replenish surface water nutrient levels (r = -0.71, p < 0.05). Finally, our results showed strong decreasing interannual trends of autumn chlorophyll-a levels from 2003-2022 (r < -0.66, p < 0.05), potentially due to heightened N-limitation. Hence, the effects of declining phytoplankton productivity on LI’s fisheries and marine ecosystems should be further investigated.
Abstract
Phytoplankton play a major role in marine ecosystem health. They form the base of aquatic food webs, but under conditions of nutrient loading and high stratification, they [...]
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Thermo-mechanical analysis of laminated composites shells exposed to fire
R. Pacheco, D. Di Capua, J. García-Espinosa, O. Casals

Engineering Structures (2020). Engineering Structures, 253 (2020) 113679

Abstract
This paper describes the research performed within the scope of H2020 project FIBRESHIP in the development and validation of a thermo-mechanical model to assess the ﬁre performance of composite structures. A one-dimensional thermal model with pyrolisis is used to obtain the temperature prole across the thickness and later introduced in the thermomechanical model with a quadrilateral shell element approach. The composite constitutive model employed is the socalled Serial/Parallel Rule of Mixtures (SPROM) which has been modied to introduce the eﬀect of the thermal deformation. A set of experimental tests are then used to validate the correctness of the numerical method proposed. The experimental data used to validate the thermal model is the classic Henderson experimental test. The thermomechanical coupling is validated against an original vertical furnace test of a FRP ships bulkhead following on the 2010 FTP Code standards. These validations demonstrate the correctness and accuracy of the proposed decoupled thermomechanical formulation.
Abstract
This paper describes the research performed within the scope of H2020 project FIBRESHIP in the development and validation of a thermo-mechanical model to assess the ﬁre [...]
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El Pacte Nacional per a la Indústria i la reconversió turística
M. Puig, G. Congrés2025

Abstracts_4rceec (2024). 225
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Cooperative financing funds
E. Serrano

Abstracts_4rceec (2024). 219

Abstract
Cooperative financing channels is an issue that has been an issue for the sector since the creation of the first cooperative enterprises. In the same way that capitalist companies need financing to consolidate, improve and promote their activities, cooperatives face the same need. This study analyzes the financing needs of cooperative enterprises based on a survey of one hundred Catalan cooperatives. In addition to analyzing the results obtained, these are also compared with the results of the latest survey on access to finance prepared by the European Central Bank (ECB, 2023).
Abstract
Cooperative financing channels is an issue that has been an issue for the sector since the creation of the first cooperative enterprises. In the same way that capitalist companies [...]
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CHAPTER 9: SOLVOLYSIS AND BIOLOGICAL RECYCLING OF COMPOSITES. OBTAINING RAW MATERIALS
P. Aguar, N. Miazza

libro-blanco-materiales-compuestos (2024). 49

Abstract
This chapter analyses the chemical recycling technique by solvolysis and by biological recycling, explaining that it involves breaking the polymer chain by using reactive solvents, temperature, catalysts, and pressure in the first case, and enzymes and microorganisms in the second. The situation of both technologies is shown, i.e. the operating parameters found in the literature for each type of polymer. In the case of solvolysis, the companies that are currently commercializing this technology are listed; there are still no companies for the case of biological recycling as its technology readiness level (TRL) is lower than for solvolysis. The chapter ends with recommendations for future developments for both types of solvolysis.
Abstract
This chapter analyses the chemical recycling technique by solvolysis and by biological recycling, explaining that it involves breaking the polymer chain by using reactive [...]
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CHAPTER 8: REVALUATION OF PYROLYSIS PRODUCTS
A. Lopez-Urionabarrenechea, A. Serras-Malillos, N. Gastelu, B. Perez-Martinez, E. Acha, B. Caballero, I. Marco

libro-blanco-materiales-compuestos (2024). 50

Abstract
This chapter describes the physical-chemical properties and market options of pyrolysis oils and pyrolysis gases coming from residual fiber-reinforced plastic materials. The description focuses on the pyrolysis products generated from the two predominant types of resin in these materials, i.e. epoxy and unsaturated polyester, from both production and end-of-life waste. Pyrolysis oils and gases have two potential industrial applications: the petroleum refining and petrochemical industries, and the alternative fuels market, namely, refuse derived fuels (RDF). However, it can be observed throughout the chapter that the physical-chemical properties of these two products are far from the standards currently required by the industry. Finally, the state of the art of the research on the optimization possibilities of these products is presented, highlighting a successful case where the oils are eliminated and hydrogen-rich gases are generated, increasing the economic profitability of the pyrolysis processes applied to this kind of waste.
Abstract
This chapter describes the physical-chemical properties and market options of pyrolysis oils and pyrolysis gases coming from residual fiber-reinforced plastic materials. The [...]
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CHAPTER 7: RECYCLING AND RECOVERY TECHNOLOGIES OF CARBON AND GLASS FIBERS BY PYROLYSIS
O. Rodriguez Largo, F. A.López

libro-blanco-materiales-compuestos (2024). 51

Abstract
Of all the recycling technologies available for recycling fiber-reinforced composite materials, pyrolysis is one of the most frequently used. This technology allows the recovery of long fibers with good mechanical properties in addition to reusing the resin in the form of energy. This chapter describes this technology, including some variations of it, such as microwave-assisted pyrolysis. It can be concluded that pyrolysis is a suitable technology for the recovery of long fibers, maintaining between 70-95% of their initial mechanical properties. Furthermore, pyrolysis applied to reinforced composites is a technology currently used at an industrial level, both in Europe and in Spain.
Abstract
Of all the recycling technologies available for recycling fiber-reinforced composite materials, pyrolysis is one of the most frequently used. This technology allows the recovery [...]
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CHAPTER 6: MANAGEMENT OF COMPOSITE MATERIALS AT THE END OF USE: CURRENT SITUATION
A. Chiminelli, M. Lizaranzu, C. Crespo

libro-blanco-materiales-compuestos (2024). 52

Abstract
This chapter presents a review of the current situation in Spain, in relation to Europe and the world, regarding the treatment of composite materials and their constituents at the end of their life cycle. Such treatment may include landfill disposal, energy recovery (incineration), recycling or recovery of materials as raw materials for the same or other uses, or the reuse or repurposing at the component or subcomponent level. These pathways or processes, along with associated developments and research, are described in greater depth in subsequent sections, while this section provides a general, combined, and particularized review, as much as possible, of the Spanish case. The chapter covers three main areas: a general framework, a section on initiatives and services offered by private companies, and a section on the activities of groups, centers, and entities within the R&D sector. Issues related to legislation, including waste classification, are presented in a specific chapter dedicated to this topic.
Abstract
This chapter presents a review of the current situation in Spain, in relation to Europe and the world, regarding the treatment of composite materials and their constituents [...]
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CAPÍTULO 5: IDENTIFICACIÓN DE LOS COMPOSITES PARA SU RECICLADO
X. Fernández-Sánchez-Romate, M. Martínez

libro-blanco-materiales-compuestos (2024). 53

Abstract
Currently, there is a growing interest in the development of reusable polymer matrix composite materials. In this regard, it is commonly known that although thermoplastic matrices can be reprocessed, they generally have worse mechanical properties, and their processing is much more complex than that of thermoset matrices, due to the high viscosities involved during manufacturing processes [1]. Therefore, the development of new thermoset matrices that can be reused is key. In this context, solutions such as polymers based on dynamic covalent bonds emerge, which allow the material to be reprocessed by heating it above its Tg [2], as seen in previous chapters. This would allow reprocessing similar to that of thermoplastic polymers, enabling these composite materials to be used again for new applications. Therefore, considering the development of these new materials and the existing concerns about developing more sustainable manufacturing techniques and materials, the need arises to establish new methods for the proper identification of both the composite material waste generated and those composite materials that are recycled, i.e., those that are reused. Products can be labeled to facilitate better recovery at the end of their useful life (End of Life, EOL), especially due to the wide variety of possible material compositions in composite materials. Labeling is mandatory for certain plastic products in the automotive industry (including composite materials) according to the End-of-Life Vehicle (ELV) directive [3]. There are standards for labeling products in other sectors. Some high-value products in the aerospace and automotive industries now incorporate Radio Frequency Identification (RFID) tags for tracking product life cycle management (Product Life Management, PLM) and ensuring provenance and traceability. These tags may contain data about the material to facilitate higher-value recycling and could be linked to virtual databases that include material origin, manufacturing, and usage data throughout the entire life cycle. Proper identification of components can also be done through the Digital Product Passport proposed as part of the ESPR (Ecodesign for Sustainable Products Regulation) [4], to maintain adequate traceability of products in terms of material technical characteristics, repair information, etc., so that consumers have a complete understanding of the materials and their environmental impact, in order to establish appropriate reuse techniques. The ESPR, in turn, aims to design components that result in more reliable, durable, reusable, repairable, easy-to-maintain, recyclable, and energy-sustainable products. In addition, waste can be classified using EWC codes (European Waste Catalogue). This can enable proper identification of waste that may be more hazardous or waste that could be reused at the end of its first life cycle. Therefore, this chapter aims to address, in a simple manner, those methods for identifying composite materials, both focused on the traceability of products through digital passports, and for managing the waste generated during their service life using EWC codes.
Abstract
Currently, there is a growing interest in the development of reusable polymer matrix composite materials. In this regard, it is commonly known that although thermoplastic [...]
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yagya
D. Qu

Collection of Articles on Social Sciences (2024). 1

Abstract
Navigating the complex landscape of adolescence in the digital age presents unique challenges, with social media, technological divides, and academic pressures intensifying the already demanding expectations placed on teenagers. This study explores the role of Emotional Intelligence (EI) in ethical decision-making among high school students. Emotional Intelligence, encompassing abilities such as self-awareness, empathy, and emotional regulation, plays a crucial role in understanding and managing emotions, which is essential for ethical reasoning. A survey was conducted among 68 students from an ethnically and academically diverse suburban high school, assessing their EI levels and ethical decision-making capabilities through a series of dilemmas. The results indicate a significant correlation between higher EI scores and better ethical decision-making abilities. Respondents with higher EI were more adept at navigating moral dilemmas, suggesting that EI serves as a valuable predictor of ethical behavior. Additionally, a secondary survey compared students' theoretical ethical choices with their anticipated real-life actions, highlighting the influence of peer pressure and social norms on decision-making. The findings underscore the importance of fostering EI skills in educational settings to better equip students for the ethical challenges they will face. This study contributes to the growing body of literature on the intersection of EI and ethics, emphasizing the need for holistic educational approaches that prioritize emotional and ethical development. Future research should expand to diverse populations and employ longitudinal methods to further elucidate the causal relationships between EI and ethical decision-making.
Abstract
Navigating the complex landscape of adolescence in the digital age presents unique challenges, with social media, technological divides, and academic pressures intensifying [...]
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CHAPTER 4: LIFE CYCLE ASSESSMENT METHODOLOGY
E. Tellechea, M. Lasheras, I. Landa, U. Larraya

libro-blanco-materiales-compuestos (2024). 54

Abstract
Life Cycle Assessment (LCA) of composite materials is the use of a systematic approach to assess environmental impacts throughout all stages of the life cycle. This methodology includes defining the objectives and scope of the study, data collection, impact assessment and interpretation of results. This chapter presents the specific considerations for the LCA of composite materials, analyzing related works on this topic. It is concluded that most of the work published to date uses LCA as a tool for comparative studies between traditional solutions (mostly metallic structures) and lightweight composite solutions. The authors observe that there has also been an increase in the use of green or bio-based composites in the recent years, made from natural fibers and/or resins.
Abstract
Life Cycle Assessment (LCA) of composite materials is the use of a systematic approach to assess environmental impacts throughout all stages of the life cycle. This methodology [...]
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CHAPTER 3: SITUATION OF COMPOSITE MATERIALS IN SPAIN
I. Idareta, N. Salmerón, T. Blanco, E. Guerra, M. Cerdeira, S. Díaz, L. Iniesta

libro-blanco-materiales-compuestos (2024). 55

Abstract
Composite materials play a very relevant role in various sectors, thanks to the lightweighting they can accomplish. Their implementation has been steadily increasing in recent decades, accompanied by the development of processes and equipment that facilitate and optimize their implementation. Spain is one of the leading European countries in the implementation of these materials and technologies, with leading companies and research centers both in terms of application and technological innovation, which continue to work on expanding the use of composites and advancing their sustainability.
Abstract
Composite materials play a very relevant role in various sectors, thanks to the lightweighting they can accomplish. Their implementation has been steadily increasing in recent [...]
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CHAPTER 2: SCOPE OF STUDY AND APPLICATION
J. Sanchez

libro-blanco-materiales-compuestos (2024). 56
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CHAPTER 1: MOTIVATION
J. Sanchez, A. Güemes

libro-blanco-materiales-compuestos (2024). 57
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