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• Phase-field modelling and computation of fracture in partially saturated porous media

  L. Lorenzis

  Videos of Plenary Lectures presented at the VIII International Conference on Coupled Problems in Science and Engineering (COUPLED 2019).

  
  

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• Simulated reality: Intelligence augmentation systems that employ real-time simulation and augmented reality

  E. Cueto

  Videos of Plenary Lectures presented at the VIII International Conference on Coupled Problems in Science and Engineering (COUPLED 2019).

  
  

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• Solving coupled problems in the realm of fracturing processes of saturated and unsaturated porous media

  W. Ehlers

  Videos of Plenary Lectures presented at the VIII International Conference on Coupled Problems in Science and Engineering (COUPLED 2019).

  
  

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• Structure-preserving discretization in space and time of coupled problems

  P. Betsch

  Videos of Plenary Lectures presented at the VIII International Conference on Coupled Problems in Science and Engineering (COUPLED 2019).

  
  

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• Advanced solid elements for sheet metal forming simulation

  V. Mataix Ferrándiz, R. Rossi, E. Oñate, F. flores

  (2016). Journal of Physics: Conferences Series, Cesar de Sa J. M. A., Neto E. S., Cardoso R. P. R., Adetoro O. B. (eds), Vol. 734 (3), pp. 032128

  
  

  Abstract

  The solid-shells are an attractive kind of element for the simulation of forming processes, due to the fact that any kind of generic 3D constitutive law can be employed without any additional hypothesis. The present work consists in the improvement of a triangular prism solid-shell originally developed by Flores. The solid-shell can be used in the analysis of thin/thick shell, undergoing large deformations. The element is formulated in total Lagrangian formulation, and employs the neighbour (adjacent) elements to perform a local patch to enrich the displacement field. In the original formulation a modified right Cauchy-Green deformation tensor (C) is obtained; in the present work a modified deformation gradient (F) is obtained, which allows to generalise the methodology and allows to employ the Pull-Back and Push-Forwards operations. The element is based in three modifications: (a) a classical assumed strain approach for transverse shear strains (b) an assumed strain approach for the in-plane components using information from neighbour elements and (c) an averaging of the volumetric strain over the element. The objective is to use this type of elements for the simulation of shells avoiding transverse shear locking, improving the membrane behaviour of the in-plane triangle and to handle quasi-incompressible materials or materials with isochoric plastic flow.

  Abstract
  The solid-shells are an attractive kind of element for the simulation of forming processes, due to the fact that any kind of generic 3D constitutive law can be employed without [...]

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• Generació de malles estructurades a partir d'equacions el·líptiques

  R. Codina

  (1990). Research Report, Nº PI7

  
  

  Abstract

  En aquest treball es descriu un mètode de generació de malles estructurades d'elements finits basat en imposar que les línies coordenades satisfacin una equació el·líptica, analitzant l'efecte de diferents termes amb les incògnites sense derivar d'aquesta equció sobre la malla resultant. Les equacions que cal resoldre es descrititzen en diferències finites, adaptant-hi les tècniques anomenades d'upwind pròpies del mètode dels elements finits. Es presenta també una tècnica de resolució del sistema algebraic d'equacions resultant. 

  Abstract
  En aquest treball es descriu un mètode de generació de malles estructurades d'elements finits basat en imposar que les línies coordenades satisfacin [...]

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• Métodos avanzados para el cálculo de la resistencia de la última de estructuras de hormigón

  E. Oñate, A. Hanganu

  (1999). Research Report, Nº PI176

  
  

  Abstract

  Se presenta en el trabajo una panorámica de los modelos más recientes para evaluar la resistencia última de estructuras de hormigón en masa y armado. Se presta especial atención al modelo de daño, descubriéndose varios ejemplos de aplicación de este modelo. 

  Abstract
  Se presenta en el trabajo una panorámica de los modelos más recientes para evaluar la resistencia última de estructuras de hormigón en masa y armado. [...]

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• A large strain plasticity model for anisotropic composite materials

  E. Car, S. Oller, E. Oñate

  (1999). Research Report, Nº PI179

  
  

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• Higher-order simulations: Strategic investment under model-induced market structures

  G. Peffer, B. Llacay

  (2004). Research Report, Nº PI261

  
  

  Abstract

  The trading and investment decision processes in financial markets becomes ever more dependent on the use of valuation and risk models. In certain, cases such as risk management, modelling practice has become so homogeneous that one is led to ask about the effect this has on the price formation process. Furthermore, should stable price patterns emerge from this, can sophisticated investors who have private information about the use and characteristics of these models make superior gains? The aim of this article is to test this hypothesis in a stylised market environment, where a strategic trader who trades on information about the valuation and risk management models used by competitors. Results show that for our particular market setting, such a strategy has an advantage over those that do not use this information.

  Abstract
  The trading and investment decision processes in financial markets becomes ever more dependent on the use of valuation and risk models. In certain, cases such as risk management, [...]

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• Smeared crack approach: Back to the original track

  M. Cervera, M. Chiumenti

  (2006). Research Report, Nº PI295

  
  

  Abstract

  This paper reviews briefly the formulations used over the last 40 years for the solution of problems involving tensile cracking, both with the discrete and smeared crack approaches. The paper focuses in the smeared approach, identifying as its main drawbacks the observed mesh-size and mesh-bias spurious dependence when the method is applied “straightly”. A simple isotropic local damage constitutive model is considered, and the (exponential) softening modulus is regularized according to the material fracture energy and the element size. The continuum and discrete mechanical problems corresponding to both the weak discontinuity (smeared cracks) and strong discontinuity (discrete cracks) approaches are analyzed and the question of propagation of the strain localization band (crack) is identified as the main difficulty to be overcome in the numerical procedure. A tracking technique is used to ensure uniqueness of the solution, attaining the necessary stability and convergence properties of the corresponding discrete finite element formulation. Numerical examples show that the formulation derived is well posed, stable and remarkably robust. As a consequence, the results obtained do not suffer from spurious meshsize or mesh-bias dependence, comparing very favorably with those obtained with other fracture and continuum mechanics approaches.

  Abstract
  This paper reviews briefly the formulations used over the last 40 years for the solution of problems involving tensile cracking, both with the discrete and smeared crack [...]

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