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• Posibilidades de las nuevas tecnologías de información y comunicaciones en el sector de la construcción

  E. Oñate, J. Marcipar, F. Zárate

  (2003). Research Report, Nº PI221

  
  

  Abstract

  Se presenta una breve panorámica de las posibilidades de las nuevas Tecnologías de la Información y las Comunicaciones en el sector de la construcción. Tras unas reflexiones sobre el valor intrínseco de la información y las comunicaciones, se describe el impacto que está teniendo Internet en los nuevos métodos de trabajo, de comercio, de formación y, en general, de intercambio de información a todos los niveles en las actividades de los técnicos del sector de la construcción. Finalmente se especula sobre las posibilidades de las TIC para generar entornos de trabajo inteligentes que generen y gestionen conocimiento para la solución de problemas prácticos.

  Abstract
  Se presenta una breve panorámica de las posibilidades de las nuevas Tecnologías de la Información y las Comunicaciones en el sector de la construcción. [...]

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• Ship hydrodynamics

  E. Oñate, J. García-Espinosa, S. Idelsohn

  (2003). Research Report, Nº PI222

  
  

  Abstract

  This chapter presents an overview of some computational methods for analysis of ship hydrodynamics problems. Attention is focused on the description of a stabilized finite element formulation derived via a finite calculus procedure. Both arbitrary Lagrangian-Eulerian (ALE) and fully Lagrangian forms are presented. Details of the treatment of the free-surface waves and the interaction between the ship structure and the sea water are also given. Examples of application to a variety of ship hydrodynamics problems are shown.

  Abstract
  This chapter presents an overview of some computational methods for analysis of ship hydrodynamics problems. Attention is focused on the description of a stabilized finite [...]

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• A general stabilized formulation for incompressible fluid flow using finite calculus and the finite element method

  E. Oñate, J. García-Espinosa, G. Bugeda, S. Idelsohn

  (2003). Research Report, Nº PI223

  
  

  Abstract

  We present a general formulation for incompressible fluid flow analysis using the finite element method (FEM). The necessary stabilization for dealing with convective effects and the incompressibility condition are introduced via the so called finite calculus (FIC) method. The extension of the standard eulerian form of the equations to an arbitrary lagrangian-eulerian (ALE) frame adequate for treating fluid-structure interaction problems is presented. The fully lagrangian form is also discussed. Details of an effective mesh updating procedure are presented together with a method for dealing with free surface effects of importance for ship hydrodynamic analysis and many other fluid flow problems. Examples of application of the eulerian, the ALE and the fully lagrangian flow descriptions are presented.

  Abstract
  We present a general formulation for incompressible fluid flow analysis using the finite element method (FEM). The necessary stabilization for dealing with convective effects [...]

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• Numerical simulation of gear pumps

  G. Houzeaux, R. Codina

  (2003). Research Report, Nº PI224

  
  

  Abstract

  We present in this paper a complete numerical strategy for the study of two gear pumps. This work includes all the steps to follow from the treatment of the CAD geometry until the analysis of the simulation results. In particular, we treat the CAD simplification, the meshing of the geometry, the numerical strategy and, finally, the analysis of simulation results.

  Abstract
  We present in this paper a complete numerical strategy for the study of two gear pumps. This work includes all the steps to follow from the treatment of the CAD geometry until [...]

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• Softening, localization and stabilization: capture of discontinuous solutions in J2 plasticity

  M. Cervera, M. Chiumenti, C. Agelet de Saracibar

  (2003). Research Report, Nº PI227

  
  

  Abstract

  This paper exploits the concept of stabilization techniques to improve the behaviour of mixed linear/linear simplicial elements (triangles and tetrahedra) in incompressible or nearly incompressible situations. Elasto‐J2‐plastic constitutive behaviour has been considered with linear and exponential softening. Two different stabilization methods are used to attain global stability of the corresponding discrete finite element formulation. Implementation and computational aspects are also discussed, showing that a robust application of the proposed formulation is feasible. Numerical examples show that the formulation derived is free of volumetric locking and spurious oscillations of the pressure. The results obtained do not suffer from spurious mesh‐size or mesh‐bias dependence, comparing very favourably with those obtained with the standard, non‐stabilized, approaches.

  Abstract
  This paper exploits the concept of stabilization techniques to improve the behaviour of mixed linear/linear simplicial elements (triangles and tetrahedra) in incompressible [...]

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• Implementación del flujo potencial en CALTEP

  R. Silva, F. Zárate, S. Idelsohn

  (2003). Research Report, Nº PI228

  
  

  Abstract

  La presente Tesis de Master tiene como objetivo la modificación del programa CALTEP2000 estacionario, el cual estudia la transmisión de calor mediante el Método de Elementos Finitos (MEF). Esta modificación pretende adaptar dicho programa al estudio aerodinámico en problemas de fluidos con la aproximación de Flujo Potencial. De esta forma, la adaptación permite soslayar un problema numérico que surge, en fenómenos de flujo alrededor de objetos aerodinámicos que presentan un borde de fuga, si no se toman las precauciones adecuadas. Una vez obtenida esta adaptación, se procede a validarla con un perfil de ala sencillo y el programa educativo ED-Poiss y, posteriormente, con un cilindro circular y con perfiles NACA-63012A y NACAM-12. Debido a la complejidad de estos últimos, se utiliza para validarlos el programa comercial DesignFOIL, especializado en el estudio de perfiles de ala.

  Abstract
  La presente Tesis de Master tiene como objetivo la modificación del programa CALTEP2000 estacionario, el cual estudia la transmisión de calor mediante el Método [...]

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• Nonlinear dynamic analysis of RC Frame under earthquake loading

  H. Kwak, E. Oñate, S. Kim

  (2003). Research Report, Nº PI229

  
  

  Abstract

  Nonlinear dynamic analysis of a reinforced concrete (RC) frame under earthquake loading is performed in this paper on the basis of a hysteretic moment-curvature relation. Unlike previous analytic moment-curvature relations which take into account the flexural deformation only with the perfect-bond assumption, the proposed relation considers the rigid-body-motion due to anchorage slip at the fixed end, which accounts for more than 50% of the total deformation, using an equivalent flexural stiffness. The advantages of the proposed relation, compared with the layered section approach and multi-component model, may be on the easiness in application to a complex structure composed of many element and on the reduction in calculation time and memory space. The use of curved unloading and reloading branches inferred from the stress-strain relation of steel and consideration of the pinching effect caused by axial force made it possible to describe the structural response more exactly. Finally, correlation studies between analytical and experimental results are conducted to establish the applicability of the proposed model to the nonlinear dynamic analysis of RC structures.

  Abstract
  Nonlinear dynamic analysis of a reinforced concrete (RC) frame under earthquake loading is performed in this paper on the basis of a hysteretic moment-curvature relation. [...]

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• Numerical modelling of void inclusions in porous media

  A. Rodríguez-Ferran, J. Sarrate, A. Huerta

  (2003). Research Report, Nº PI230

  
  

  Abstract

  Numerical modelling of porous flow in a low-permeability with high-permeability inclusions is a challenging task, because the large ratio of permeabilities ill-conditions the finite element system of equations. We propose a coupled model where Darcy flow is used for the porous matrix and potential flow the inclusions. We discuss appropriate interface conditions in detail and show that the head drop in the inclusions can be prescribed in a very simple way. Algorithmic aspects are treated in full detail. Numerical examples show that this coupled approach precludes ill-conditioning and is more efficient than heterogeneous Darcy flow.

  Abstract
  Numerical modelling of porous flow in a low-permeability with high-permeability inclusions is a challenging task, because the large ratio of permeabilities ill-conditions [...]

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• Efficient and reliable nonlocal damage models

  A. Rodríguez-Ferran, I. Morata, A. Huerta

  (2003). Research Report, Nº PI231

  
  

  Abstract

  We present an efficient and reliable approach for the numerical modelling of failure with nonlocal damage models. The two major numerical challenges – the strongly nonlinear, highly localized and parameter-dependent structural response of quasi-brittle materials, and the interaction between non-adjacent finite element associated to nonlocality – are addressed in detail. Efficiency is achieved with a suitable combination of load-stepping control technique and nonlinear solver for equilibrium equations. Reliability of the numerical results is ensured by an h-adaptive strategy based on error estimation. We use a residual-type error estimator for nonlinear FE analysis based on local computations, which, at the same time, accounts for the nonlocality of damage model. The proposed approach is illustrated by means of three application examples: the three-point bending test, the single-edge notched beam and Brazilian test. In addition, we present a new nonlocal damage model based on nonlocal displacements. Its good qualitative behaviour and attractive numerical properties are discussed and illustrated by means of a uniaxial tension test.

  Abstract
  We present an efficient and reliable approach for the numerical modelling of failure with nonlocal damage models. The two major numerical challenges – the strongly nonlinear, [...]

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• Pseudo-divergence-free element free Galerkin method for incompressible fluid flow

  A. Huerta, Y. Vidal, P. Villon

  (2003). Research Report, Nº PI232

  
  

  Abstract

  Incompressible modelling in finite elements has been a major concern since its early developments and has been extensively studied. However, incompressibility in mesh-free method is still an open topic. Thus, instabilities or locking can preclude the use of mesh-free approximations in such problems. Here, a novel mesh-free formulation is proposed for incompressible flow. It is based on defining a pseudo-divergence-free interpolation space. That is, the finite dimensional interpolation space approaches a divergence-free space when the discretization is refined. Note that such an interpolation does not include any overhead I the computations. The numerical evaluations are performed using the inf-sup numerical test and two well-known benchmark examples for Stokes flow.

  Abstract
  Incompressible modelling in finite elements has been a major concern since its early developments and has been extensively studied. However, incompressibility in mesh-free [...]

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