Laboratorio CAD/CAM/CAE

URI permanente para esta comunidad

https://hdl.handle.net/10784/9117

Está en la capacidad de prestar servicios y entrenar asistentes para el mercado internacional en investigación y desarrollo de herramientas para diseño, manufactura y mecánica asistidos por computador (CAD/CAM/CAE).

Líneas de investigación: Applied Computational Geometry; Computational Mechanics; Computer Aided Geometric Design; Computer Aided Manufacturing; Geometric Modeling of Cultural Heritage; Geometric Modeling of Materials; Geometric Modeling of Terrain and Coastal Areas; Medical Images; Medical Kinematics; Robot Kinematics.
Código Minciencias: COL0013067.
Categoría 2019: A1.
Escuela: Ingeniería.
Departamento académico: Ingeniería Mecánica.
Coordinador: Juan Manuel Rodríguez Prieto.
Correo electrónico:jmrodrigup@eafit.edu.co

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Mostrando 1 - 20 de 218

2D shape similarity as a complement for Voronoi-Delone methods in shape reconstruction
(PERGAMON-ELSEVIER SCIENCE LTD, 2005-02-01) Ruiz, O.E.; Cadavid, C.A.; Granados, M.; Peña, S.; Vásquez, E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
In surface reconstruction from planar cross sections it is necessary to build surfaces between 2D contours in consecutive cross sections. This problem has been traditionally attacked by (i) direct reconstruction based on local geometric proximity between the contours, and (ii) classification of topological events between the cross sections. These approaches have been separately applied with limited success. In case (i), the resulting surfaces may have overstretched or unnatural branches. These arise from local contour proximity which does not reflect global similarity between the contours. In case (ii), the topological events are identified but are not translated into the actual construction of a surface. This article presents an integration of the approaches (i) and (ii). Similarity between the composite 2D regions bounded by the contours in consecutive cross sections is used to: (a) decide whether a surface should actually relate two composite 2D regions, (b) identify the type and location of topological transitions between cross sections and (c) drive the surface construction for the regions found to be related in step (a). The implemented method avoids overstretched or unnatural branches, rendering a surface which is both geometrically intuitive and topologically faithful to the cross sections of the original object. The presented method is a good alternative in cases in which correct reproduction of the topology of the surface (e.g. simulation of flow in conduits) is more important than its geometry (e.g. assessment of tumor mass in radiation planning). © 2004 Elsevier Ltd. All rights reserved.
2D Shape similarity as a complement for Voronoi-Delone methods in shape reconstruction
(Elsevier, 2005) Ruíz S., Óscar E.; Cadavid, Carlos A.; Granados, Miguel; Peña, Sebastián; Vásquez, Eliana; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
In surface reconstruction from planar slices it is necessary to build surfaces between corresponding 2D regions in consecutive levels -- The problem has been traditionally attacked with (i) direct reconstruction based on local geometric proximity between the regions, and (ii) classification of topological events between the slices, which control the evolution of the cross cuts -- These approaches have been separately applied with mixed success -- In the case (i), the results may be surfaces with over-stretched or unnatural branches, resulting from a local contour proximity which does not correspond to global similarity between regions -- In (ii), the consequences from topological events upon the actual surface realization have not been drawn -- In this paper an integration of (i) and (ii) is presented, which uses a criteria of similarity between composed 2D regions in consecutive slices to: (a) decide if a surface should actually relate those regions, (b) identify the topological transitions between levels and (c) construct the local surface for the related regions -- The method implemented hinders over-stretched and unnatural branches, therefore rendering a surface which adjusts to geometrically-sound topological events -- This is a good alternative when the surface reconstructed needs to be topologically faithful (for example in flow simulation) in addition to represent the a rough geometrical space (for example in radiation planning)
Accelerated Thermal Simulation for Three-Dimensional Interactive Optimization of Computer Numeric Control Sheet Metal Laser Cutting
(American Society of Mechanical Engineers (ASME), 2017-12-21) Mejía, D.; Moreno, Aitor; Arbelaiz, Ander; Posada, Jorge; Ruiz, O.; Chopitea, Raúl; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
Accelerated Thermal Simulation for Three-Dimensional Interactive Optimization of Computer Numeric Control Sheet Metal Laser Cutting
(American Society of Mechanical Engineers (ASME), 2018-03-01) Mejia D.; Moreno A.; Arbelaiz A.; Posada J.; Ruiz-Salguero O.; Chopitea R.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
In the context of computer numeric control (CNC)-based sheet metal laser cutting, the problem of heat transfer simulation is relevant for the optimization of CNC programs. Current physically based simulation tools use numeric or analytic algorithms which provide accurate but slow solutions due to the underlying mathematical description of the model. This paper presents: (1) an analytic solution to the laser heating problem of rectangular sheet metal for curved laser trajectories and convective cooling, (2) a graphics processing unit (GPU) implementation of the analytic solution for fast simulation of the problem, and (3) an integration within an interactive environment for the simulation of sheet metal CNC laser cutting. This analytic approach sacrifices the material removal effect of the laser cut in the favor of an approximated real-time temperature map on the sheet metal. The articulation of thermal, geometric, and graphic feedback in virtual manufacturing environments enables interactive redefinition of the CNC programs for better product quality, lower safety risks, material waste, and energy usage among others. The error with respect to finite element analysis (FEA) in temperature prediction descends as low as 3.5%. Copyright © 2018 by ASME.
Adaptative cubical grid for isosurface extraction
(2009) Congote, John; Moreno, Aitor; Barandiaran, Iñigo; Barandiaran, Javier; Ruíz, Óscar E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
This work proposes a variation on the Marching Cubes algorithm, where the goal is to represent implicit functions with higher resolution and better graphical quality using the same grid size -- The proposed algorithm displaces the vertices of the cubes iteratively until the stop condition is achieved -- After each iteration, the difference between the implicit and the explicit representations are reduced, and when the algorithm finishes, the implicit surface representation using the modified cubical grid is more detailed, as the results shall confirm -- The proposed algorithm corrects some topological problems that may appear in the discretisation process using the original grid
Adaptative cubical grid forisosurface extraction
(2009-01-01) Congote, J.; Moreno, A.; Barandiaran, I.; Barandiaran, J.; Ruiz, O.E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
This work proposes a variation on the Marching Cubes algorithm, where the goal is to represent implicit functions with higher resolution and better graphical qualiry using the same grid size. The proposed algorithm displaces the vertices of the cubes iteratively until the stop condition is achieved. After each iteration, the difference betvveen the implicit and the explicit representations are reduced, and when the algorithm finishes, the implicit surface representation using the modified cubical grid is more detailed, as the results shall confirm. The proposed algorithm corrects some topological problems that may appear in the discretisation process using the original grid.
Advanced HCI and 3D Web over Low performance Devices
(2012-07) Oyarzun, David; Del Pozo, Arantza; Congote, John Edgar; Olaizola, Igor G.; Sainz, Iñaki; Leturia, Igor; Arregi, Xabier; Ruíz, Óscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
This position paper presents the authors’ goals on advanced human computer interaction and 3D Web -- Previous work on speech, natural language processing and visual technologies has achieved the development of the BerbaTek language learning demonstrator, a 3D virtual tutor that supports Basque language students through spoken interaction -- Next steps consist on migrating all the system to multidevice web technologies -- This paper shows the architecture defined and the steps to be performed in the next months
Advanced HCI and 3D web over low performance devices
(CEUR-WS, 2012-01-01) Oyarzun, D.; Del Pozo, A.; Congote, J.E.; Olaizola, I.G.; Sainz, I.; Leturia, I.; Arregi, X.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
This position paper presents the authors' goals on advanced human computer interaction and 3D Web. Previous work on speech, natural language processing and visual technologies has achieved the development of the BerbaTek language learning demonstrator, a 3D virtual tutor that supports Basque language students through spoken interaction. Next steps consist on migrating all the system to multidevice web technologies. This paper shows the architecture defined and the steps to be performed in the next months.
Algebraic Geometry and Group Theory in Geometric Constraint Satisfaction for Computer Aided Design and Assembly Planning
(1996-01-01) RUIZ, OSCAR EDUARDO; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
Algebraic geometry and group theory in geometric constraint satisfaction for computer-aided design and assembly planning
(Taylor & Francis, 1996) Ruíz, Óscar E.; Ferreira, Placid M.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
Mechanical design and assembly planning inherently involve geometric constraint satisfaction or scene feasibility (GCS/SF) problems -- Such problems imply the satisfaction of proposed relations placed between undefined geometric entities in a given scenario -- If the degrees of freedom remaining in the scene are compatible with the proposed relations or constraints, a set of entities is produced that populate the scenario satisfying the relations -- Otherwise, a diagnostic of inconsistency of the problem is emitted -- This problem appears in various forms in assembly planning (assembly model generation), process planning, constraint driven design, computer vision, etc -- Previous attempts at solution using separate numerical, symbolic or procedural approaches suffer serious shortcomings in characterizing the solution space, in dealing simultaneously with geometric (dimensional) and topological (relational) inconsistencies, and in completely covering the possible physical variations of the problem -- This investigation starts by formulating the problem as one of characterizing the solution space of a set of polynomials -- By using theories developed in the area of algebraic geometry, properties of Grobner Bases are used to assess the consistency and ambiguity of the given problem and the dimension of its solution space -- This method allows for die integration of geometric and topological reasoning -- The high computational cost of Grobner Basis construction and the need for a compact and physically meaningful set of variables lead to the integration of known results on group theory -- These results allow the characterization of geometric constraints in terms of the subgroups of the Special Group of Euclidean displacements in E^3, SE(3) -- Several examples arc developed which were solved with computer algebra systems (MAPLE and Mathematica) -- They are presented to illustrate the use of the Euclidean group-based variables, and to demonstrate the theoretical completeness of the algebraic geometry analysis over the domain of constraints expressible as polynomials
Algorithms for reconstruction of 3D surfaces for anthropometric modeling
(INGEGRAF, 2000) Ruíz Salguero, O.; Schrader Gil, R.; Acosta Duarte, J.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
Los protocolos de medición antropométrica se caracterizan por la profusión de medidas discretas o localizadas, en un intento para caracterizar completamente la forma corporal del sujeto -- Dichos protocolos se utilizan intensivamente en campos como medicina deportiva, forense y/o reconstructiva, diseño de prótesis, ergonomía, en la confección de prendas, accesorios, etc -- Con el avance de algoritmos de recuperación de formas a partir de muestreos (digitalizaciones) la caracterización antropométrica se ha alterado significativamente -- El articulo presente muestra el proceso de caracterización digital de forma corpórea, incluyendo los protocolos de medición sobre el sujeto, el ambiente computacional - DigitLAB- (desarrollado en el CII-CAD-CAM-CG de la Universidad EAFIT) para recuperación de superficies, hasta los modelos geométricos finales -- Se presentan comparaciones de los resultados obtenidos con DigitLAB y con paquetes comerciales de recuperación de forma 3D -- Los resultados de DigitLAB resultan superiores, debido principalmente al hecho de que este toma ventaja de los patrones de las digitalizaciones (planares de contacto, por rejilla de pixels - range images -, etc.) y provee módulos de tratamiento geométrico - estadístico de los datos para poder aplicar efectivamente los algoritmos de recuperación de forma -- Se presenta un caso de estudio dirigido a la industria de la confección, y otros efectuados sobre conjuntos de prueba comunes en el ámbito científico para la homologación de algoritmos
Analytical method for the kinetostatic analysis of the second-class RRR ASSUR Group allowing for friction in the kinematic pairs
(SciELO Brasil, 2010) Durango, Sebastián; Calle, Gabriel; Ruíz, Oscar; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
The calculation of forces in the kinematic pairs of mechanisms by inverse dynamics is usually performed without friction considerations -- In practice, when examination of articulated mechanisms takes into account friction, the solution of the inverse dynamics results in a complex procedure -- If a modular approach for the inverse dynamics is used, then exact solutions are available, but not necessarily are practical -- For example, the analytical solution for a second-class first-type Assur group is a 16th degree equation -- Previous researches proposed an approximated but practical (graphical) method to calculate the forces on the kinematic pairs taking into account the friction forces -- In this article, an analytical interpretation of the Artobolevski approximated method is developed for the second-class Assur group with three rotational pairs -- The final results for the reactions calculated with the implemented method present a good approximation with respect to the graphical solution -- Future work should consider friction forces not only in second-class groups with rotational joints, but also in second-class groups with prismatic joints and high-class Assur groups
Analytical method for the kinetostatic analysis of the second-class RRR assur group allowing for friction in the kinematic pairs
(Springer Berlin Heidelberg, 2010-07-01) Durango, S.; Calle, G.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
The calculation of forces in the kinematic pairs of mechanisms by inverse dynamics is usually performed without friction considerations. In practice, when examination of articulated mechanisms takes into account friction, the solution of the inverse dynamics results in a complex procedure. If a modular approach for the inverse dynamics is used, then exact solutions are available, but not necessarily are practical. For example, the analytical solution for a second-class first-type Assur group is a 16th degree equation. Previous researches proposed an approximated but practical (graphical) method to calculate the forces on the kinematic pairs taking into account the friction forces. In this article, an analytical interpretation of the Artobolevski approximated method is developed for the second-class Assur group with three rotational pairs. The final results for the reactions calculated with the implemented method present a good approximation with respect to the graphical solution. Future work should consider friction forces not only in second-class groups with rotational joints, but also in second-class groups with prismatic joints and high-class Assur groups. Copyright © 2010 by ABCM.
Appraisal of open software for finite element simulation of 2D metal sheet laser cut
(Springer-Verlag France, 2017-08-01) Mejia, D.; Moreno, A.; Ruiz-Salguero, O.; Barandiaran, I.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
FEA simulation of thermal metal cutting is central to interactive design and manufacturing. It is therefore relevant to assess the applicability of FEA open software to simulate 2D heat transfer in metal sheet laser cuts. Application of open source code (e.g. FreeFem++, FEniCS, MOOSE) makes possible additional scenarios (e.g. parallel, CUDA, etc.), with lower costs. However, a precise assessment is required on the scenarios in which open software can be a sound alternative to a commercial one. This article contributes in this regard, by presenting a comparison of the aforementioned freeware FEM software for the simulation of heat transfer in thin (i.e. 2D) sheets, subject to a gliding laser point source. We use the commercial ABAQUS software as the reference to compare such open software. A convective linear thin sheet heat transfer model, with and without material removal is used. This article does not intend a full design of computer experiments. Our partial assessment shows that the thin sheet approximation turns to be adequate in terms of the relative error for linear alumina sheets. Under mesh resolutions better than m , the open and reference software temperature differ in at most 1 of the temperature prediction. Ongoing work includes adaptive re-meshing, nonlinearities, sheet stress analysis and Mach (also called 'relativistic') effects.
Appraisal of open software for finite element simulation of 2D metal sheet laser cut.
(Springer-Verlag France, 2016-03-21) Mejia, Daniel; Moreno, Aitor; Ruiz Salguero, Oscar; Barandiaran, Inigo; Universidad EAFIT. Departamento de Ingeniería Mecánica. Grupo de Investigación CAD CAM CAE, Carrera 49 7 Sur-50, Medellín, Colombia.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
FEA simulation of thermal metal cutting is central to interactive design and manufacturing. It is therefore relevant to assess the applicability of FEA open software to simulate 2D heat transfer in metal sheet laser cuts. Application of open source code (e.g. FreeFem++, FEniCS, MOOSE) makes possible additional scenarios (e.g. parallel, CUDA, etc.), with lower costs. However, a precise assessment is required on the scenarios in which open software can be a sound alternative to a commercial one. This article contributes in this regard, by presenting a comparison of the aforementioned freeware FEM software for the simulation of heat transfer in thin (i.e. 2D) sheets, subject to a gliding laser point source. We use the commercial ABAQUS software as the reference to compare such open software. A convective linear thin sheet heat transfer model, with and without material removal is used. This article does not intend a full design of computer experiments. Our partial assessment shows that the thin sheet approximation turns to be adequate in terms of the relative error for linear alumina sheets. Under mesh resolutions better than 10e−5 m , the open and reference software temperature differ in at most 1 % of the temperature prediction. Ongoing work includes adaptive re-meshing, nonlinearities, sheet stress analysis and Mach (also called ‘relativistic’) effects.
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/CAE
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.
Approximation of the Mechanical Response of Large Lattice Domains Using Homogenization and Design of Experiments
(Universitatea Politehnica Bucuresti, 2020-06-01) Montoya, D.; Acosta, D.; Cortes, C.; Pareja, J.; Moreno, Aitor; Posada, Jorge; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
Aspect ratio- and size-controlled patterned triangulations of parametric surfaces
(ACTA PRESS ANAHEIM, 2007-01-01) Ruiz, Oscar E.; Pena, Sebastian; Duque, Juan; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
A method to produce patterned, controlled size triangulation of Boundary Representations is presented. Although the produced patterned triangulations are not immediately suited for fast visualization, they were used in Fixed Grid Finite Element Analysis, and do provide a control on the aspect ratio or shape factor of the triangles produced. The method presented first calculates a triangulation in the parameter space of the faces in which the B-Rep is partitioned and then maps it to 3D space. Special emphasis is set in ensuring that the triangulations of neighboring faces meet in a seamless manner, therefore ensuring that a borderless C2 2-manifold would have as triangulation a C0 borderless 2-manifold. The method works properly under the conditions (i) the parametric form of the face is a 1-1 function, (ii) the parametric pre-image of a parametric face is a connected region, and (iii) the user-requested sampling frequency ( samples per length unit ) is higher than twice the spatial frequency of the features in the B-Rep ( thus respecting the Nyquist principle ). As the conditions (i) and (ii) are possible under face reparameterization or sub-division and the condition (iii) is the minimum that a triangulation should comply with, the method is deemed as generally applicable.
Aspect ratio-and size-controlled patterned triangulations of parametric surfaces
(2007-02) Ruíz, Óscar E.; Peña, Sebastián; Duque, Juan; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
A method to produce patterned, controlled size triangulation of Boundary Representations is presented -- Although the produced patterned triangulations are not immediately suited for fast visualization, they were used in Fixed Grid Finite Element Analysis, and do provide a control on the aspect ratio or shape factor of the triangles produced -- The method presented first calculates a triangulation in the parameter space of the faces in which the B-Rep is partitioned and then maps it to 3D space -- Special emphasis is set in ensuring that the triangulations of neighboring faces meet in a seamless manner, therefore ensuring that a borderless C2 2-manifold would have as triangulation a C0 borderless 2-manifold -- The method works properly under the conditions(i) the parametric form of the face is a 1-1 function, (ii) the parametric pre-image of a parametric face is a connected region, and (iii) the user-requested sampling frequency (samples per length unit ) is higher than twice the spatial frequency of the features in the B-Rep ( thus respecting the Nyquist principle ) -- As the conditions (i) and (ii) are possible under face reparameterization or sub-division and the condition (iii) is the minimum that a triangulation should comply with, the method is deemed as generally applicable
Automatic Tools for Data Diagnostic and Correction in Aerophotogrametry
(INGEGRAF, 1999) Ruíz Salguero, Óscar E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
En Aerofotogrametría, el proceso de restitución (paso de imagen a formato electrónico vectorizado) es realizado por un operador humano, con asistencia de hardware y Software especializado -- Dicho proceso implica la traducción de accidentes geográficos, detalles topográficos, etc., la cual conlleva errores tanto geométricos (precisión) como topológicos (conectividad) de los datos digitales vectorizados -- Adicionalmente, aun si la vectorizacion es perfecta, los editores en etapas subsecuentes deben realizar tareas repetitivas: formateo, marcado, ajuste de convenciones, etc., que por el tamaño de los archivos de datos se hacen prolongadas y propensas al error -- Tanto los procesos de corrección como de formateo y marcado requieren además la ejecución de entradas / salidas con el usuario en el computador, proceso que es particularmente lento -- Esta investigación presenta el desarrollo de herramientas automáticas de (i) detección y corrección de errores comunes en los planos restituidos, (ii) partición y re-agrupación inteligentes de planos grandes, y (iii) formateo y marcado automático -- El desarrollo de software se hace usando el standard AIS (Application Interface Specification), lo que lo hace portable a los modeladores cuya interface AIS haya sido implementada -- El proyecto se desarrolla para la firma AeroEstudios LTDA de Colombia, la cual lo ha incorporado a sus herramientas de procesamiento de información digital

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