Documents published in Scipedia

• Assessing Scaling and Kinematic Errors in a Coupled Experimental-Computational Infant Musculoskeletal Model

  T. Chambers, C. Walck, V. Huayamave, E. Mannen

  coupled2023.

  
  

  Abstract

  Musculoskeletal models are valuable tools that enable the study and quantification of biomechanical parameters, allowing researchers to better understand the mechanisms influencing or contributing to human movement. Furthermore, musculoskeletal models have the potential to serve as diagnostic tools for identifying pathologies and disorders, such as developmental dysplasia of the hip. However, current musculoskeletal models are developed using adult subjects, with only a few studies focusing on infant populations, despite the greatest growth rate being in early infancy. Therefore, the objective of this study was to evaluate the impact of multiple linear scaling approaches of increasing complexity on the development of an infant musculoskeletal model. Motion capture technology was used to collect data from the spontaneous kicking movement of a 2.4-month-old infant lying supine. The experimental motion capture data and anthropometric measurements were used to scale the generic gait2392 OpenSim model. Four linear scaling methods of increasing complexity were used: uniform (Uni), nonuniform (Non), nonuniform with knee and ankle joint centers (NAKJCs), and nonuniform with knee, ankle, and regression-derived hip joint centers (NHJCs). Results suggest that the maximum marker errors decreased with the increasing complexity of the scaling approach. The Uni scaling approach resulted in the largest scaling and kinematic errors, with maximum marker errors of 4.92 cm and 5.30 cm, respectively. The NHJCs scaling approach had the lowest maximum marker errors, with errors of 4.17 cm and 4.36 cm, respectively. The scaling method used to develop infant musculoskeletal models should be considered carefully, especially when using linearly scaling generic models developed using adult cadaveric data.

  Abstract
  Musculoskeletal models are valuable tools that enable the study and quantification of biomechanical parameters, allowing researchers to better understand the mechanisms influencing [...]

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• A Novel Musculoskeletal-driven Exoskeleton Framework for Spina Bifida Rehabilitation in Infants

  V. Huayamave, T. Chambers, E. Vela, W. Kim, E. Centero, B. Macumber

  coupled2023.

  
  

  Abstract

  Soft exoskeletons are lightweight robotic devices currently used for physical therapy and rehabilitation. Most of the current research on soft exoskeletons has focused on the adult population, providing limited options for infant physical therapy and rehabilitation. Spina bifida, a condition affecting the infant’s brain and spinal cord, requires muscle movement treatment through physical therapy. Coupling physiological infant movement with soft robotics can provide solutions for rehabilitation and physical therapy. This study couples joint kinematics from a novel musculoskeletal model with a soft-robotic exoskeleton that uses vacuum-powered artificial muscles. The accuracy of the exoskeleton is assessed when replicating physiological infant kicks. Knee joint kinematics from the musculoskeletal model during infant movement were used to drive the soft exoskeleton. Preliminary results showed that the robotic system replicated infant kicks with lower frequency and small ranges of motion (RMS < 2 degrees) more accurately than those with higher frequency and large ranges of motion (RMS > 6 degrees). The proposed framework has the potential to replicate physiological infant kicks that could be used for infant physical therapy and rehabilitation.

  Abstract
  Soft exoskeletons are lightweight robotic devices currently used for physical therapy and rehabilitation. Most of the current research on soft exoskeletons has focused on [...]

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• A mechanobiological bone remodelling model coupling bone physiology and systemic calcium and phosphorus homeostasis

  J. Martínez-Reina, J. Calvo-Gallego, F. Gutiérrez-Milán, P. Pivonka

  coupled2023.

  
  

  Abstract

  In this work we couple a physiologically based mathematical model of integrated calcium and phosphorus homeostasis to a cell population bone remodelling model and to a pharmacokinetics (PK) - pharmacodynamics (PD) model of denosumab (Dmab), an antiresorptive drug administered to combat osteoporosis (OP). The model of Ca and P homeostasis allows to incorporate the effect of factors such as Ca dietary changes, vitamin D supplementation, concurrence of renal deficiency or hyperparathyroidism into the study of OP and its treatment.

  Abstract
  In this work we couple a physiologically based mathematical model of integrated calcium and phosphorus homeostasis to a cell population bone remodelling model and to a pharmacokinetics [...]

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• An HPC Multi-Physics Framework for Next-Generation Industrial Aircraft Simulations

  E. Fadiga, F. Rondina, T. Benacchio, D. Malacrida, L. Capone, S. Oliani

  coupled2023.

  
  

  Abstract

  The aerodynamic performance of industrial aircraft is strongly coupled with the structural deformation under aerodynamic load. Consequently, multi-physics simulations represent an important asset during the design and optimization phases. Most of the Fluid-Structure Interaction (FSI) coupling approaches adopted by researchers and engineers can be divided into monolithic and partitioned techniques. The monolithic coupling, which consists of a unique system of equations for the coupled problem, is usually characterized by higher robustness and easier scalability. However, this approach is inherently customized for specific applications and requires a significant development effort. The partitioned coupling links existing software on a higher level, benefitting from higher flexibility and lower time-to-solution. As the computational world marches towards the exascale, black-box coupling libraries such as preCICE [2] aim to combine the flexibility and user-friendliness of partitioned approaches with complete and efficient usage of the available computational power. This paper focuses on aeroelasticity analyses currently performed at the Leonardo Labs facilities, exploiting the recently installed davinci-1 supercomputer [14]. Open-source CFD and structural dynamics software applications are coupled using preCICE to conduct fully threedimensional FSI analyses of aeroelastic test cases of industrial interest. The activities are part of a broader Digital Innovation industrial strategy centred on Digital Twins combining high-fidelity, highly scalable numerical simulations with data-driven AI models.

  Abstract
  The aerodynamic performance of industrial aircraft is strongly coupled with the structural deformation under aerodynamic load. Consequently, multi-physics simulations represent [...]

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• Hemodynamic evaluation of aortic aneurysms using FSI simulations

  B. Chitneedi, C. Karliampas

  coupled2023.

  
  

  Abstract

  The work focuses on understanding aortic blood flow dynamics and emphasize the importance of considering the flexible aortic wall model in assessing cardiovascular health and identifying potential risk factors for aneurysm and related conditions. In this paper, a fluidstructure interaction (FSI) study of vascular blood flow based on the partitioned approach using open-source software tools, OpenFOAM for Computational Fluid Dynamics (CFD) and CalculiX for Computational Structural Mechanics (CSM), coupled through the preCICE tool is presented. The FSI simulations were performed on raw and simplified (based on area of interest) patient-specific models of aneurysmatic blood vessels, considering Newtonian fluid and laminar flow assumptions. The arterial wall was modeled using the CalculiX’s isotropic linear elastic model and the communication of data is handled by preCICE. The biomedical metrics such as the Time-Averaged Wall Shear Stress (TAWSS) and the Oscillatory Shear Index (OSI) in correlation with cardiac cycles were quantified to predict rupture prone regions.

  Abstract
  The work focuses on understanding aortic blood flow dynamics and emphasize the importance of considering the flexible aortic wall model in assessing cardiovascular health [...]

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• Data-Parallel Radial-Basis Function Interpolation in preCICE

  D. Schneider, T. Schrader, B. Uekermann

  coupled2023.

  
  

  Abstract

  We present data-parallel approaches to solve radial-basis function interpolation problems in the context of partitioned multi-physics simulations, where interpolation methods are required to transfer coupling data between non-matching vertex clouds. Data-parallel approaches are a key component for the efficient use of accelerator cards and thus for performance portability on modern compute platforms. The presented approach is integrated into the open-source coupling library preCICE. After discussing different implementation strategies, we introduce a solution based on thelinear algebra library Ginkgo, which provides a common abstraction layer for cross-platform performance with focus on solving sparse linear systems. The new implementation exploits accelerator cards for both, matrix assembly as well as solving the resulting linear system. The capability of the presented approach is compared to already existing implementations in preCICE using a turbine blade geometry

  Abstract
  We present data-parallel approaches to solve radial-basis function interpolation problems in the context of partitioned multi-physics simulations, where interpolation methods [...]

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• Implementation and Formulation of a Multi-Region, Electromagnetic Solver for Discontinuous Media

  A. Bogaers, W. Roos, Q. Reynolds, J. Zietsman

  coupled2023.

  
  

  Abstract

  The formulation and implementation of a finite-volume, multi-region, electromagnetic solver into OpenFOAM, and coupled using preCICE is presented, to enable the solution of electromagnetic problems with large material discontinuities.

  Abstract
  The formulation and implementation of a finite-volume, multi-region, electromagnetic solver into OpenFOAM, and coupled using preCICE is presented, to enable the solution [...]

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• Partitioned Flow Simulations with preCICE and OpenFOAM

  M. Mühlhäußer, G. Chourdakis, B. Uekermann

  coupled2023.

  
  

  Abstract

  Large and heterogeneous flow simulations could benefit from partitioning, where each subdomain is solved by an individual, dedicated code. In this paper, we investigate and validate the fluid-fluid module of the preCICE-OpenFOAM adapter by coupling two incompressible OpenFOAM fluid solvers via a surface Dirichlet-Neumann coupling approach. The results of various simple test cases are compared to monolithic OpenFOAM simulations. By utilizing a special pressure boundary condition, the coupled results show only a small error around the coupling interface. The magnitude of this error depends on the velocity gradient, the mesh width, as well as the cell orthogonality. Looking into the OpenFOAM source code reveals that higher accuracy is only possible by manipulating the solvers themselves and thereby violating the black-box approach of preCICE. The fluid-fluid module is extended to couple temperature with sufficient accuracy for one validation case. Furthermore, support for multiphase flow solvers is added to the adapter. Lastly, custom inlet-outlet boundary conditions are implemented for pressure and velocity, which switch their behavior dynamically, depending on the flow direction. The results shown in this presentation provide a basis for future fluid-fluid coupling applications with preCICE.

  Abstract
  Large and heterogeneous flow simulations could benefit from partitioning, where each subdomain is solved by an individual, dedicated code. In this paper, we investigate and [...]

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• Towards Computational Efficient Fully Coupled Aeroelastic Simulations of Turbomachinery Blades with TRACE and CalculiX

  M. Freimuth, C. Berthold, F. Herbst

  coupled2023.

  
  

  Abstract

  In the industrial design of turbomachinery blades their aeroelastic behaviour is most commonly investigated by methods, that use linearization or rely on unidirectional coupling. To circumvent the limitations of those methods a new fully coupled simulation in the time domain with the structural solver CalculiX and the turbomachinery CFD solver TRACE is currently developed and presented in this paper. The coupling library preCICE is chosen to couple the mentioned elaborated single physics solvers due to its focus on high performance computing applications. Within this work the preCICE adapter for CalculiX has recently been enabled to work with a special CalculiX method, that allows to investigate dedicated eigenforms of the blades or other structural objects. It is furthermore shown that the use of this CalculiX method can lead to a massive speedup for use cases, where the structural dynamics response can be well described by a piece-wise linear approximation within each increment. On the other hand a completely new preCICE adapter for TRACE has been developed and is introduced here. The preCICE-coupled system of CalculiX and TRACE is successfully validated against a TRACE-internal coupling approach by investigating a simple testcase with a NACA profile blade that shows good agreement.

  Abstract
  In the industrial design of turbomachinery blades their aeroelastic behaviour is most commonly investigated by methods, that use linearization or rely on unidirectional coupling. [...]

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• Implementing a Comprehensive Hydromechanical Model for Sedimentary Basins by Coupling a 3D Mechanical Code to a Classic Basin Fluid Flow Code with the PreCICE Library

  J. Gratien, D. Colombo, S. Chaisemartin, A. Pasteau, B. Vialey

  coupled2023.

  
  

  Abstract

  In this paper, we present a coupling strategy for the implementation of a comprehensive hydromechanical model for sedimentary basins [1]. The preCICE framework [2] has been used to efficiently implement an iterative coupling scheme between ArcTem, a sedimentary basin fluid flow code, and Code Aster [20], a finite element general purpose mechanical code. We discuss several issues related to different domain partitions used by the parallel codes, to the time evolutivity of the 3D meshes and to the different time stepping used by each code. We have used the preCICE framework communication system to efficiently exchange data between the codes and to interpolate fields between usually non-matching meshes. The iterative coupling scheme is managed by means of the functionalities provided by preCICE. We validate our coupled code on a real sedimentary basin study [19]. We evaluate the flexibility of the preCICE framework to efficiently implement advanced iterative coupling algorithms. We compare the performance of our solution to a standard approach based on a centralized supervisor controlling the coupling flow and using files to exchange data between the codes.

  Abstract
  In this paper, we present a coupling strategy for the implementation of a comprehensive hydromechanical model for sedimentary basins [1]. The preCICE framework [2] has been [...]

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