Examinando por Autor "Cortés C."
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Ítem Approximation of the mechanical response of large lattice domains using homogenization and design of experiments(Universitatea Politehnica Bucuresti, 2020-01-01) Montoya-Zapata D.; Acosta D.A.; Cortés C.; Pareja-Corcho J.; Moreno A.; Posada J.; Ruiz-Salguero O.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de ProcesosLattice-based workpieces contain patterned repetition of individuals of a basic topology (Schwarz, ortho-walls, gyroid, etc.) with each individual having distinct geometric grading. In the context of the design, analysis and manufacturing of lattice workpieces, the problem of rapidly assessing the mechanical behavior of large domains is relevant for pre-evaluation of designs. In this realm, two approaches can be identified: (1) numerical simulations which usually bring accuracy but limit the size of the domains that can be studied due to intractable data sizes, and (2) material homogenization strategies that sacrifice precision to favor efficiency and allow for simulations of large domains. Material homogenization synthesizes diluted material properties in a lattice, according to the volume occupancy factor of such a lattice. Preliminary publications show that material homogenization is reasonable in predicting displacements, but is not in predicting stresses (highly sensitive to local geometry). As a response to such shortcomings, this paper presents a methodology that systematically uses design of experiments (DOE) to produce simple mathematical expressions (meta-models) that relate the stress-strain behavior of the lattice domain and the displacements of the homogeneous domain. The implementation in this paper estimates the von Mises stress in large Schwarz primitive lattice domains under compressive loads. The results of our experiments show that (1) material homogenization can efficiently and accurately approximate the displacements field, even in complex lattice domains, and (2) material homogenization and DOE can produce rough estimations of the von Mises stress in large domains (more than 100 cells). The errors in the von Mises stress estimations reach 42% for domains of up to 24 cells. This result means that coarse stress-strain estimations may be possible in lattice domains by combining DOE and homogenized material properties. This option is not suitable for precise stress prediction in sensitive contexts wherein high accuracy is needed. Future work is required to refine the meta-models to improve the accuracies of the estimations. © 2020 by the authors.Ítem Approximation of the mechanical response of large lattice domains using homogenization and design of experiments(Universitatea Politehnica Bucuresti, 2020-01-01) Montoya-Zapata D.; Acosta D.A.; Cortés C.; Pareja-Corcho J.; Moreno A.; Posada J.; Ruiz-Salguero O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAELattice-based workpieces contain patterned repetition of individuals of a basic topology (Schwarz, ortho-walls, gyroid, etc.) with each individual having distinct geometric grading. In the context of the design, analysis and manufacturing of lattice workpieces, the problem of rapidly assessing the mechanical behavior of large domains is relevant for pre-evaluation of designs. In this realm, two approaches can be identified: (1) numerical simulations which usually bring accuracy but limit the size of the domains that can be studied due to intractable data sizes, and (2) material homogenization strategies that sacrifice precision to favor efficiency and allow for simulations of large domains. Material homogenization synthesizes diluted material properties in a lattice, according to the volume occupancy factor of such a lattice. Preliminary publications show that material homogenization is reasonable in predicting displacements, but is not in predicting stresses (highly sensitive to local geometry). As a response to such shortcomings, this paper presents a methodology that systematically uses design of experiments (DOE) to produce simple mathematical expressions (meta-models) that relate the stress-strain behavior of the lattice domain and the displacements of the homogeneous domain. The implementation in this paper estimates the von Mises stress in large Schwarz primitive lattice domains under compressive loads. The results of our experiments show that (1) material homogenization can efficiently and accurately approximate the displacements field, even in complex lattice domains, and (2) material homogenization and DOE can produce rough estimations of the von Mises stress in large domains (more than 100 cells). The errors in the von Mises stress estimations reach 42% for domains of up to 24 cells. This result means that coarse stress-strain estimations may be possible in lattice domains by combining DOE and homogenized material properties. This option is not suitable for precise stress prediction in sensitive contexts wherein high accuracy is needed. Future work is required to refine the meta-models to improve the accuracies of the estimations. © 2020 by the authors.Ítem Approximation of the mechanical response of large lattice domains using homogenization and design of experiments(Universitatea Politehnica Bucuresti, 2020-01-01) Montoya-Zapata D.; Acosta D.A.; Cortés C.; Pareja-Corcho J.; Moreno A.; Posada J.; Ruiz-Salguero O.; Montoya-Zapata D.; Acosta D.A.; Cortés C.; Pareja-Corcho J.; Moreno A.; Posada J.; Ruiz-Salguero O.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)Lattice-based workpieces contain patterned repetition of individuals of a basic topology (Schwarz, ortho-walls, gyroid, etc.) with each individual having distinct geometric grading. In the context of the design, analysis and manufacturing of lattice workpieces, the problem of rapidly assessing the mechanical behavior of large domains is relevant for pre-evaluation of designs. In this realm, two approaches can be identified: (1) numerical simulations which usually bring accuracy but limit the size of the domains that can be studied due to intractable data sizes, and (2) material homogenization strategies that sacrifice precision to favor efficiency and allow for simulations of large domains. Material homogenization synthesizes diluted material properties in a lattice, according to the volume occupancy factor of such a lattice. Preliminary publications show that material homogenization is reasonable in predicting displacements, but is not in predicting stresses (highly sensitive to local geometry). As a response to such shortcomings, this paper presents a methodology that systematically uses design of experiments (DOE) to produce simple mathematical expressions (meta-models) that relate the stress-strain behavior of the lattice domain and the displacements of the homogeneous domain. The implementation in this paper estimates the von Mises stress in large Schwarz primitive lattice domains under compressive loads. The results of our experiments show that (1) material homogenization can efficiently and accurately approximate the displacements field, even in complex lattice domains, and (2) material homogenization and DOE can produce rough estimations of the von Mises stress in large domains (more than 100 cells). The errors in the von Mises stress estimations reach 42% for domains of up to 24 cells. This result means that coarse stress-strain estimations may be possible in lattice domains by combining DOE and homogenized material properties. This option is not suitable for precise stress prediction in sensitive contexts wherein high accuracy is needed. Future work is required to refine the meta-models to improve the accuracies of the estimations. © 2020 by the authors.Ítem FE-simulations with a simplified model for open-cell porous materials: A Kelvin cell approach(IOS Press, 2019-01-01) Montoya-Zapata D.; Cortés C.; Ruiz-Salguero O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEIn in-silico estimation of mechanical properties of open (Kelvin) cell porous materials, the geometrical model is intractable due to the large number of finite elements generated. Such a limitation impedes the study of reasonable domains. VoXel or Boundary representations of the porous domain result in FEA data sets which do not pass the stage of mesh generation, even for very modest domains. Our method to overcome such limitations partially replaces geometrical minutiae with kinematical constraints imposed on cylindrical bars (i.e. Truss model). Our implemented method uses node position equality constraints augmented with rotation constraints at the joints. Such a method significantly reduces the computational expense of the model, allowing the study of domains of 103 Kelvin cells. The results of the tests executed show the accuracy and efficiency of the Truss model in the estimation of Young's modulus and Poisson's ratio when compared with current procedures. The method allows application for materials which depart from Kelvin Cell uniformity, since the Truss model admits general configurations. As the simulation is made possible by the Truss model, new challenges appear, such as the application to anisotropic materials and the automatic generation of the Truss model from actual foam scans (e.g. tomographies). © 2019 - IOS Press and the authors. All rights reserved.Ítem Geometry simplification of open-cell porous materials for elastic deformation FEA(SPRINGER, 2019-01-01) Cortés C.; Osorno M.; Uribe D.; Steeb H.; Ruiz-Salguero O.; Barandiarán I.; Flórez J.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEEstimation of mechanical properties of porous materials is central for their medical and industrial application. However, the massive size of accurate boundary representations (B-Rep) of the foams makes the numerical estimations intractable. Even for small domain sizes, the mesh generation for finite element analysis (FEA) may not terminate. Current efforts for simulating porous materials use statistical predictions of the material structure. The simulated and actual materials present different geometry and topology, with consequences on the simulation results. To overcome these limitations, this manuscript presents a method, which (1) synthesizes an accurate truss abstraction from the raw geometry data, (2) executes efficient FEA simulations, and (3) processes nodal displacements to estimate apparent mechanical moduli of the porous material. The method addresses materials whose ligaments have circular cross-sections. The iso-surface present in the Computer Tomography (CT) scan of the porous material is used to synthesize a truss graph whose edges are truncated cones. Then, optimization and simplification methods are applied to produce a topologically and geometrically correct truss representation for the foam domain. Comparative FEA load simulations are conducted between the full B-Rep and truss representations of the material. The truss model proves to be significantly more efficient for FEA, departing from the Full B-Rep FEA by a maximum of 16% in the estimation of equivalent mechanical moduli. Geometric assessments such as porosity and Hausdorff distance confirm that the truss abstraction is a cost-effective one. Ongoing efforts concentrate on point set geometric algorithms for enforcement of standardized material testing. © 2018 Springer-Verlag London Ltd., part of Springer Nature