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• Modeling thermoplastic melt spread over different flooring materials

  K. Butler, E. Oñate, R. Rossi, J. Marti, S. Idelsohn

  (2010). Research Report, Nº PI349

  
  

  Abstract

  The effects of the thermal properties of three flooring materials on the spread rate of polymer melt over the surface were studied using a model based on the Particle Finite Element Method (PFEM). The high thermal conductivity of steel keeps the steel floor at a nearly uniform temperature throughout, whereas the ceramic and oak floors are able to sustain a higher temperature beneath the point at which the hot melt is dripping onto the surface. In general, the spread rate is controlled by the viscosity at the outer edges of the melt pool. The spread rate over steel is therefore fastest, especially for a thin floor that rapidly increases in temperature. The low thermal inertia of oak results in rapid changes in surface temperature, which traps the heat close to the interface between the floor and the melt and maintains a high temperature and low viscosity in the center of the melt pool. The ceramic floor transports heat more readily and may develop a hot spot underneath. The material properties of ceramic lie between those of oak and steel, but although the spread rate over a steel floor is always faster than over ceramic, the spread rate over oak may not always be slower.

  Abstract
  The effects of the thermal properties of three flooring materials on the spread rate of polymer melt over the surface were studied using a model based on the Particle Finite [...]

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• Interfase GiD per a la generació paramètrica de geometries trenades per a l’apantallament de cables coaxials

  R. Méndez, R. Isanta, R. Otín, O. Fruitos

  (2009). Technical Report, IT594

  
  

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• SIMPACT: Explicit Dynamic Code for non Linear Structural Analysis

  R. Otín

  (2009). Technical Report, IT585

  
  

  Abstract

  SIMPACT is a finite element computer system developed at the International Center for Numerical Methods in Engineering (CIMNE) in Barcelona, Spain, for analysis of structures subjected to dynamic and impact loading. Typical application of SIMPACT include among others the seismic analysis of structures, the study of structures subjected to internal of external vibrations, the prediction of ship motions originated by waves crashworthiness studies in automobiles, aerospace and maritime vehicles, analysis of structures subjected to blast pressure loading and a wide range of impact problems typical of defense applications.

  Abstract
  SIMPACT is a finite element computer system developed at the International Center for Numerical Methods in Engineering (CIMNE) in Barcelona, Spain, for analysis of structures [...]

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• Research Lines & RTD Project in Biomedical Engineering

  R. Project

  Technical Reports of the International Centre for Numerical Methods in Engineering (CIMNE) (2009).

  
  

  Abstract

  Computational Fluid Dynamics Solid and Structural Biomechanics Health Decision Support Systems Cardiovascular System Biomaterials Artificial Intelligence Neurosciences Medical-GiD Urology Pre and post processing

  Abstract
  Computational Fluid Dynamics Solid and Structural Biomechanics Health Decision Support Systems Cardiovascular System Biomaterials Artificial Intelligence Neurosciences Medical-GiD Urology Pre [...]

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• Implementation of an Automated Benchmarking module for Kratos

  F. Mossaiby

  (2009). Technical Report, IT571

  
  

  Abstract

  The steady and careful checking process of the test examples is almost impossible for developers and users of Kratos, and needs to be automated. This has been the inspiration of development of an Automated Benchmarking module. During the nightly builds of Kratos, which will be done on the upcoming Kratos server, this module automatically runs all test examples and verifies the results against a reference data set. It will send an email containing the status of each test example to a list of recipients. This can be useful in several ways. First, it will be clear when a conflict has occurred. This will help greatly to find the user committed the changes, ask him / her to correct / undo it. Also, it will let other users to be aware of a conflict in the latest code base, and avoid updating their own local code base, before it has been corrected. This can save them a lot of time and effort.

  Abstract
  The steady and careful checking process of the test examples is almost impossible for developers and users of Kratos, and needs to be automated. This has been the inspiration [...]

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• Comportamiento sísmico de puentes atirantados y disipación de energía adicional: un estado del conocimiento

  G. Valdebenito, A. Aparicio

  Monograph Series in Earthquake Engineering, editor A. H. Barbat (2005). MIS55

  
  

  Abstract

  Las siguientes páginas corresponden a la presentación de los últimos avances y novedades en materia de comportamiento sísmico de puentes de tirantes de gran luz. La idea ha surgido de la necesidad de unificar experiencias y criterios, y tiene como objetivo presentar al lector una visión actualizada acerca del comportamiento de estos sistemas y la reciente introducción y uso de sistemas avanzados adicionales de protección pasiva y activa. A modo introductorio, se presentan los aspectos generales del comportamiento de puentes de tirantes frente a cargas estáticas. Se exponen los resultados de las investigaciones más recientes acerca del comportamiento sísmico general de puentes de tirantes de gran luz, se analiza la problemática de la caracterización de la acción sísmica de entrada, se presentan los desarrollos y resultados de investigaciones recientes en materia de dispositivos de control de vibraciones aplicado a puentes, se analiza la temática del comportamiento sísmico de puentes de tirantes con incorporación de sistemas pasivos y activos y finalmente se presentan algunos aspectos básicos y actualizados relacionados con el análisis y diseño estructural.

  Abstract
  Las siguientes páginas corresponden a la presentación de los últimos avances y novedades en materia de comportamiento sísmico de puentes de tirantes [...]

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• Probabilistic seismic hazard and risk assessment in Spain

  M. Salgado-Gálvez, O. Cardona, M. Carreño, A. Barbat

  Monograph Series in Earthquake Engineering, editor A. H. Barbat (2015). MIS69, ISBN: 978-84-943307-7-3

  
  

  Abstract

  This work attempts to explain how probabilistic seismic risk assessments can be performed at different resolution levels, using, strictly speaking, the same methodology (or arithmetic) and, then, how to obtain results in terms of the same metrics; but, also, highlighting what the differences in terms of inputs for the analysis and the reasons for them (i.e. including the dynamic soil response effects which are only relevant in local assessments) are. First, a country level assessment is first performed with similarities to the presented by Cardona et al. (2014) using a coarse-grain exposure database that includes only the building stock in the urban regions of Spain. Second, a urban seismic risk assessment with the detail of state-of-the-art studies such as the ones developed by Marulanda et al. (2013) and Salgado-Gálvez et al (2013; 2014a) is performed for Lorca, Murcia. In both cases, the fully probabilistic seismic risk results are expressed in terms of the loss exceedance curve which corresponds to the main output of said analysis from where different probabilistic risk metrics, such as the average annual loss and the probable maximum loss, as well as several other relationships, can be derived (Marulanda et al., 2008; Bernal, 2014). Because of the damage data availability for the Lorca May 2011 earthquake, a comparison between the observed losses and those modelled using an earthquake scenario with similar characteristics in terms of location, magnitude and spectral accelerations was done for the building stock of the city. The results of the comparison are presented in terms of expected losses (in monetary terms) and damage levels related to the obtained the mean damage ratios compared with the observed by post-earthquake surveys.    

  Abstract
  This work attempts to explain how probabilistic seismic risk assessments can be performed at different resolution levels, using, strictly speaking, the same methodology (or [...]

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• Refuerzo a cortante de vigas de hormigón armado con tejidos y matrices base cemento. Análisis y comparativa

  C. Escrig, L. Gil

  Monograph CIMNE (2016). M161

  
  

  Abstract

  El principal objetivo de la presente investigación es realizar un estudio comparativo sobre la capacidad de diversos tipos de TRM actuando como refuerzo a cortante en vigas de hormigón armado de características actuales. Para lograr este propósito, se han definido unos objetivos parciales que servirán de guía en todo el proceso de elaboración y realización de la investigación.  

  Abstract
  El principal objetivo de la presente investigación es realizar un estudio comparativo sobre la capacidad de diversos tipos de TRM actuando como refuerzo a cortante [...]

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• Robust volume mesh generation for non-watertight geometries

  A. Coll, P. Dadvand, E. Oñate

  Monograph CIMNE (2014). M146

  
  

  Abstract

  Nowadays large part of the time needed to perform a numerical simulation is spent in preprocessing, especially in the geometry cleaning operations and mesh generation. Furthermore, these operations are not easy to automatize because they depend strongly on each geometrical model and they often need human interaction. Many of these operations are needed to obtain a watertight geometry. Even with a clean geometry, classical unstructured meshing methods (like Delaunay or Advancing Front based ones) present critical weak points like the need of a given quality in the boundary mesh or a relatively smooth size transition. These aspects decrease their robustness and imply an extra e ort in order to reach the nal mesh. Octree based meshers try to relax some of these requirements. In the present work an octree based mesher for unstructured tetrahedra is presented. The proposed mesher ensures the mesh generation avoiding most of the geometry cleaning operations. It is based in the following steps: t an octree onto the model, re ne it following given criteria, apply a tetrahedra pattern to the octree cells and adapt the tetrahedra close to the contours in order to represent accurately the boundary shape. An important and innovative aspect of the proposed algorithm is it ensures the nal mesh preserves the topology and the geometric features of the original model. The method uses a Ray Casting based algorithm for the identi cation of the inner and outer parts of the volumes involved in the model. This technique allows the mesh generation of volumes even with non-watertight boundaries, and also opens the use of the mesher for immersed methods only applying slight modi cations to the algorithm. The main advantages of the presented mesher are: robustness, no need for watertight boundaries, independent on the contour mesh quality, preservation of geometrical features (corners and ridges), original geometric topology guaranteed, accurate representation of the contours, valid for immersed methods, and fast performance. A lot of time in the preprocessing part of the numerical simulation is saved thanks to the robustness of the mesher, which allows skipping most of the geometry cleaning operations. A shared memory parallel implementation of the algorithm has been done. The e ectiveness of the algorithm and its implementation has been veri ed by some validation examples.

  Abstract
  Nowadays large part of the time needed to perform a numerical simulation is spent in preprocessing, especially in the geometry cleaning operations and mesh generation. Furthermore, [...]

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• Detail-preserving mesh simplification

  M. Pasenau, C. Andújar

  Monograph CIMNE (2014). M145

  
  

  Abstract

  Mesh simplification is an important problem in computer graphics. Given a polygonal mesh, the goal is to generate another mesh which approximates the underlying shape but includes less polygons, edges and vertices. Early methods focused only on preserving the overall shape of the geometric model, whereas current methods also handle meshes with attributes (normal vectors, colors, texture coordinates) so that both the mesh shape and the mesh appearance are preserved. The goal of this work is to develop, implement and test a mesh simplification algorithm able to simplify large models in-core using a vertex clustering algorithm. Several detail-preserving techniques will be examined and implemented and a new filter is proposed, taking into account geometry features and nodal defined attributes. We also review recent advances in spatial hash tables to achieve a more compact storage, and we analyze and evaluate their impact in the simplification process.

  Abstract
  Mesh simplification is an important problem in computer graphics. Given a polygonal mesh, the goal is to generate another mesh which approximates the underlying shape but [...]

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