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• The Double Hierarchy Method. A parallel 3D contact method for the interaction of spherical particles with rigid FE boundaries using the DEM

  M. Santasusana, J. Irazábal, E. Oñate, J. Puigbó

  Comp. Part. Mech (2016). Vol. 3, pp. 407-428

  
  

  Abstract

  In this work, we present a new methodology for the treatment of the contact interaction between rigid boundaries and spherical discrete elements (DE). Rigid body parts are present in most of large-scale simulations. The surfaces of the rigid parts are commonly meshed with a finite element-like (FE) discretization. The contact detection and calculation between those DE and the discretized boundaries is not straightforward and has been addressed by different approaches. The algorithm presented in this paper considers the contact of the DEs with the geometric primitives of a FE mesh, i.e. facet, edge or vertex. To do so, the original hierarchical method presented by Horner et al. (J Eng Mech 127(10):1027–1032, 2001) is extended with a new insight leading to a robust, fast and accurate 3D contact algorithm which is fully parallelizable. The implementation of the method has been developed in order to deal ideally with triangles and quadrilaterals. If the boundaries are discretized with another type of geometries, the method can be easily extended to higher order planar convex polyhedra. A detailed description of the procedure followed to treat a wide range of cases is presented. The description of the developed algorithm and its validation is verified with several practical examples. The parallelization capabilities and the obtained performance are presented with the study of an industrial application example.

  Abstract
  In this work, we present a new methodology for the treatment of the contact interaction between rigid boundaries and spherical discrete elements (DE). Rigid body parts are [...]

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• A modular, partitioned, discrete element framework for industrial grain distribution systems with rotating machinery

  G. Casas, D. Mukherjee, M. Celigueta, T. Zohdi, E. Oñate

  Comp. Part. Mech (2017). Vol. 4 (2), pp. 181-198

  
  

  Abstract

  A modular discrete element framework is presented for large-scale simulations of industrial grain-handling systems. Our framework enables us to simulate a markedly larger number of particles than previous studies, thereby allowing for efficient and more realistic process simulations. This is achieved by partitioning the particle dynamics into distinct regimes based on their contact interactions, and integrating them using different time-steps, while exchanging phase-space data between them. The framework is illustrated using numerical experiments based on fertilizer spreader applications. The model predictions show very good qualitative and quantitative agreement with available experimental data. Valuable insights are developed regarding the role of lift vs drag forces on the particle trajectories in-flight, and on the role of geometric discretization errors for surface meshing in governing the emergent behavior of a system of particles.

  Abstract
  A modular discrete element framework is presented for large-scale simulations of industrial grain-handling systems. Our framework enables us to simulate a markedly larger [...]

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• A Comparison of two objective stress rates in object-oriented codes

  A. Rodríguez-Ferran, A. Huerta

  Monograph CIMNE (1994). M26

  
  

  Abstract

  An object-oriented code, CASTEM2000, has provided the framework for algorithmic development and numerical testing. In these codes, information is stored and manipulated as objects which represent the entitiesrelevant to a finite element method computation.

  Abstract
  An object-oriented code, CASTEM2000, has provided the framework for algorithmic development and numerical testing. In these codes, information is stored and manipulated as [...]

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• A rate dependent plastic-damage constitutive model for large scale computational in concrete structures

  R. Faria, J. Oliver

  Monograph CIMNE (1993). M17

  
  

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• Composite materials non-linear modelling for long fibre-reinforced laminates: Continuum basis, computational aspects and validations

  F. Rastellini, S. Oller, O. Salomon, E. Oñate

  Computers and Structures (2008). Vol. 86 (9), pp. 879-896

  
  

  Abstract

  An innovative computational methodology is proposed for modelling the material non-linearmechanical behaviour of FRP structures. To model a single unidirectional composite lamina, a serial–parallel (SP) continuum approach has been developed assuming that components behave as parallel materials in the fibres alignment direction and as serial materials in orthogonal directions. The model is based on the appropriate management of the constitutive models of the component materials, by making use of suitable ‘closure equations’ that characterize the composite micro-mechanics [Rastellini F. Modelización numérica de la no-linealidad constitutiva de laminados compuestos. PhD thesis. ETSECCPB, Politechnical University of Catalonia, Barcelona, March, 2006. [in Spanish]]. Classical lamination theory is combined with the SP model to describe multidirectional laminates. The methodology is validated through several numerical analyses, which are contrasted against benchmark tests and experimental data taken from the world-wide failure exercise [Hinton MJ, Soden PD. Predicting failure in composite laminates: The background to the exercise. Comp Sci Technol 1998; 58:1001–10].

  Abstract
  An innovative computational methodology is proposed for modelling the material non-linearmechanical behaviour of FRP structures. To model a single unidirectional composite [...]

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• An integration of a low cost adaptive remeshing strategy in the solution of structural shape optimization problems using evolutionary methods

  G. Bugeda, J. Ródenas, E. Oñate

  Computers and Structures (2008). Vol. 86 (13-14), pp. 1563-1578

  
  

  Abstract

  Evolutionary methods are a powerful and robust tool for the solution of structural shape optimization problems. Nevertheless, the use of these methods requires the structural analysis of an important number of different designs, this making the computational cost of the analysis of each design a critical issue. For this reason, each design must be analyzed at a minimum computational cost but ensuring a minimum quality of the results. It is well known that the cheapest mesh for producing a solution with a fixed quality at minimum cost is an adapted one. Nevertheless, traditional adapted meshes are obtained from adaptive remeshing strategies, where each design has to be analyzed more than once, thereby also causing a high computational cost. This work presents a new strategy that allows generating an adapted mesh for each design without the necessity of performing a full adaptive remeshing procedure for each of them. It is based on the use of sensitivity analysis of all magnitudes related with adaptive remeshing (location of nodes, error estimation, etc.) with respect to the design variables. This sensitivity analysis is performed only once using a geometry of reference and it is used to project the results of the corresponding analysis to all other designs to be analyzed. The projected information allows generating an appropriate adapted mesh for each new design in one shot, greatly reducing the computational cost compared with standard strategies.

  Abstract
  Evolutionary methods are a powerful and robust tool for the solution of structural shape optimization problems. Nevertheless, the use of these methods requires the structural [...]

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• Análisis de problemas de choque e impacto entre sólidos deformables por el Método de los Elementos Finitos.

  J. Miquel, E. Oñate, C. Garino, S. Botello, F. Flores, J. Rojek

  Monograph CIMNE (1994). M25

  
  

  Abstract

  El trabajo que se expone ha hecho uso de los últimos avances en mecánica computacional, métodos numéricos, visualización y algoritmos de cálculo para obtener un programa de ordenador para simulación de problemas de choque e impacto de interés práctico para una amplia variedad de sectores industriales. En particular, el objetivo del proyecto SIMPACT ha sido el desarrollo de un paquete de software para análisis de problemas de dinámica rápida y análisis no lineal procesable en una amplia variedad de ordenadores, con aplicación a choques de vehículos, impacto en estructuras aeroespaciales, defensa y problemas de conformado, entre otros.

  Abstract
  El trabajo que se expone ha hecho uso de los últimos avances en mecánica computacional, métodos numéricos, visualización y algoritmos de [...]

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• Estructuras de edificación con aislaminto antisísmico

  L. Jané, A. Barbat

  Monograph CIMNE (1992). M13

  
  

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• Estimación y corrección del error en el análisis estructural por el MEF

  G. Bugeda

  Monograph CIMNE (1991). M9

  
  

  Abstract

  En los últimos años se han desarrollado diversas técnicas para resolver el problema de la estimación y la corrección del error. De hecho, la mayoría de los avances que se han realizado dentro del campo de los elementos finitos se pueden entender como formas distingas de minimizar el error existente en las soluciones. En esta monografía se hablará de dos técnicas distintas para la corrección de errores: Técnicas de refinamiento y técnicas de remallado.

  Abstract
  En los últimos años se han desarrollado diversas técnicas para resolver el problema de la estimación y la corrección del error. De hecho, [...]

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• Modelización numérica de materiales friccionales

  S. Oller

  Monograph CIMNE (1991). M10

  
  

  Abstract

  La presente monografía trata el problema del comportamiento de los materiales friccionales, especialmente del hormigón, más allá de su límite elástico. Estudia los problemas de aplastamiento y fractura y describe un modelo constitutivo amplio que permite una muy adecuada simulación de estos fenómenos.

  Abstract
  La presente monografía trata el problema del comportamiento de los materiales friccionales, especialmente del hormigón, más allá de su límite [...]

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