Repositorio Institucional Universidad EAFIT ::Examinando por Materia "Computer aided design"

Examinando por Materia "Computer aided design"

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Aerodynamic effects of manufacturing tolerances on a solar car
(Springer Science and Business Media Deutschland GmbH, 2017-01-01) Betancur, E.; Fragassa, C.; Coy, J.; Hincapie, S.; Osorio-Gómez, G.
In the case of solar vehicles, since the primary necessity is to optimise the energy efficiency during motion, many efforts are addressed by designers in searching the perfect aerodynamics. It means, in particular, the minimization of the drag force at cruising speeds and an elaborated vehicle’s Computer-Aided Design (CAD) are the principal result of this activity. Despite, these efforts can be nullified by geometrical tolerances emerging from manufacturing. In this paper, the effects of tolerances introduced by composite manufacturing processes are investigated combining 3D scanning technology and Computational Fluid Dynamics (CFD). After the solar car manufacturing, a reverse engineering process is executed with the aim to scan the vehicle’s body and compare it to the initial theoretical design. Geometric deviations are found and their aerodynamic consequences are evaluated in terms of aerodynamic losses. © Springer International Publishing AG 2017.
AIR-MODELLING: A tool for gesture-based solid modelling in context during early design stages in AR environments
(ELSEVIER SCIENCE BV, 2015-01-01) Arroyave-Tobon, Santiago; Osorio-Gomez, Gilberto; Cardona-McCormick, Juan F.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
Augmented reality (AR) technologies are just being used as interface in CAD tools allowing the user to perceive 3D models over a real environment. The influence of the use of AR in the conceptualization of products whose configuration, shape and dimensions depend mainly on the context remains unexplored. We aimed to prove that modelling in AR environments allows to use the context in real-time as an information input for making the iterative design process more efficient. In order to prove that, we developed a tool called AIR-MODELLING in which the designer is able to create virtual conceptual products by hand gestures meanwhile he/she is interacting directly with the real scenario. We conducted a test for comparing designers' performance using AIR-MODELLING and a traditional CAD system. We obtained an average reduction of 44% on the modeling time in 76% of the cases. We found that modelling in AR environments using the hands as interface allows the designer to quickly and efficiently conceptualize potential solutions using the spatial restrictions of the context as an information input in real-time. Additionally, modelling in a natural scale, directly over the real scene, prevents the designer from drawing his/her attention on dimensional details and allows him/her to focus on the product itself and its relation with the environment. © 2014 Elsevier B.V. All rights reserved.
AIR-MODELLING: A tool for gesture-based solid modelling in context during early design stages in AR environments
(ELSEVIER SCIENCE BV, 2015-01-01) Arroyave-Tobon, Santiago; Osorio-Gomez, Gilberto; Cardona-McCormick, Juan F.; Arroyave-Tobon, Santiago; Osorio-Gomez, Gilberto; Cardona-McCormick, Juan F.; Universidad EAFIT. Departamento de Ciencias; Lógica y Computación
Augmented reality (AR) technologies are just being used as interface in CAD tools allowing the user to perceive 3D models over a real environment. The influence of the use of AR in the conceptualization of products whose configuration, shape and dimensions depend mainly on the context remains unexplored. We aimed to prove that modelling in AR environments allows to use the context in real-time as an information input for making the iterative design process more efficient. In order to prove that, we developed a tool called AIR-MODELLING in which the designer is able to create virtual conceptual products by hand gestures meanwhile he/she is interacting directly with the real scenario. We conducted a test for comparing designers' performance using AIR-MODELLING and a traditional CAD system. We obtained an average reduction of 44% on the modeling time in 76% of the cases. We found that modelling in AR environments using the hands as interface allows the designer to quickly and efficiently conceptualize potential solutions using the spatial restrictions of the context as an information input in real-time. Additionally, modelling in a natural scale, directly over the real scene, prevents the designer from drawing his/her attention on dimensional details and allows him/her to focus on the product itself and its relation with the environment. © 2014 Elsevier B.V. All rights reserved.
Assembly planning with automated retrieval of assembly sequences from CAD model information
(EMERALD GROUP PUBLISHING LIMITED, 2012-01-01) Vigano, Roberto; Osorio Gomez, Gilberto; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
Purpose - The purpose of this paper is to define an approach to extract the liaison graph from a 3D CAD model and analyze a method to find at least a feasible assembly sequence for the product. The method could be useful to search the optimal sequence of assembling for a product, by comparing different sequences extracted in automatic mode from a 3D CAD model. Design/methodology/ approach - The method proposed analyzes the liaison graph extracted, in order to obtain the possible assembly sequences for the product under study. The extraction of the sequences is based on some attributes and parameters of the graph. Findings - By means of the method proposed it is possible to obtain in automatic mode the liaison graph of an assembly 3D CAD model. Moreover, the study of the graph obtained allows the definition of all the assembly sequences for the product. Finally, it is possible to analyse the sequences found to select the optimal sequence. Research limitations/implications - The major limitation of the approach is, actually, the great number of impossible sequences that are extracted. For this, a little intervention by the user is required. Practical implications - The application of the method allows the manufacturer to analyze and study the optimal assembly sequence without the direct use of a CAD system. The approach could be used at the early stage of the design process and by means of the database of the PDM/PLM systems. Originality/value - The approach proposed in the paper is an original method to extract a liaison graph from a 3D CAD model. The approach to extract the assembly sequences was compared with other methods and good results have been obtained. © Emerald Group Publishing Limited.
Automatic assembly sequence exploration without precedence definition
(Springer-Verlag France, 2013-01-01) Viganò, R.; Osorio Gómez, G.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
Today the assembly sequence for the products is often carried out manually and its definition, typically, is very expensive, not guaranteeing optimal solutions. Coming up with an efficient assembly sequence is the essential step to improve process productivity and reduces the time and costs related to assembly machines and equipment. The issue related to the assembly sequence of a product depends on the total number of the its components. In particular, the number of the possible sequences can be obtained through the calculus of the factorial of the number of the product components. This work presents an automatic approach intended to define assembly sequences, based on the information regard the contacts and the interferences existing among the components, which is obtained by the assembly CAD model of the product. The level of the information required by this approach allows its implementation at early stages of design, as soon as the layout of the conceptual solution of the product is defined, independently by the method used to model the CAD assembly. The procedure proposed is focused to obtain a reduced number of assembly sequences, guaranteeing that there is at least one feasible assembly sequence among them. The procedure is oriented to iteratively identify independent and important subassemblies into the CAD assembly, then merge them to specific assembling nodes and generate sequences until the whole product is analyzed. After a brief review of current methodologies developed for assembly planning, in this paper, the automated procedure for assembly sequence generation is explained and applied on an example, obtaining feasible solutions. © 2012 Springer-Verlag.
Ergonomic analysis in conceptual design stage using a gesture-based modelling tool
(Springer-Verlag France, 2017-08-01) Arroyave-Tobón, S.; Osorio-Gómez, G.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
Commonly, ergonomic analysis of the products' assembly processes starts in the embodiment design phase, when the information of the parts and their interaction are clearly defined. This may imply iterations during the design process for making improvements associated with ergonomic issues. We asked whether it is possible to infer possible ergonomic issues related to the manual assembly process during product conceptualisation. So, we integrated an AR-based modelling tool, in which the user creates and places virtual parts over the context in a top-down design strategy using his/her hands as interface, with an Ergonomic Assessment Module for continuous evaluation of the user postures, movements and forces related to the created parts. In that way, the spectrum of the potential solutions during the conceptualisation phase, when the information about the problem is vague enough, can be delimited and the convergence to the near-optimal solution may be more effective.
Exploración de la metodología top down design en sistemas CAD para el desarrollo de un modelo de ingeniería
(2006) Arango Rodríguez, Carlos Enrique; Paramo Bermúdez, Gabriel Jaime
Hybrid geometry / topology based mesh segmentation for reverse engineering
(PERGAMON-ELSEVIER SCIENCE LTD, 2018-06-01) Mejia D.; Ruiz-Salguero O.; Sánchez J.R.; Posada J.; Moreno A.; Cadavid C.A.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
Mesh segmentation and parameterization are crucial for Reverse Engineering (RE). Bijective parameterizations of the sub-meshes are a sine-qua-non test for segmentation. Current segmentation methods use either (1) topologic or (2) geometric criteria to partition the mesh. Reported topology-based segmentations produce large sub-meshes which reject parameterizations. Geometry-based segmentations are very sensitive to local variations in dihedral angle or curvatures, thus producing an exaggerated large number of small sub-meshes. Although small sub-meshes accept nearly isometric parameterizations, this significant granulation defeats the intent of synthesizing a usable Boundary Representation (compulsory for RE). In response to these limitations, this article presents an implementation of a hybrid geometry / topology segmentation algorithm for mechanical workpieces. This method locates heat transfer constraints (topological criterion) in low frequency neighborhoods of the mesh (geometric criterion) and solves for the resulting temperature distribution on the mesh. The mesh partition dictated by the temperature scalar map results in large, albeit parameterizable, sub-meshes. Our algorithm is tested with both benchmark repository and physical piece scans data. The experiments are successful, except for the well - known cases of topological cylinders, which require a user - introduced boundary along the cylinder generatrices. © 2018 Elsevier Ltd
Hybrid geometry / topology based mesh segmentation for reverse engineering
(PERGAMON-ELSEVIER SCIENCE LTD, 2018-06-01) Mejia D.; Ruiz-Salguero O.; Sánchez J.R.; Posada J.; Moreno A.; Cadavid C.A.; Mejia D.; Ruiz-Salguero O.; Sánchez J.R.; Posada J.; Moreno A.; Cadavid C.A.; Universidad EAFIT. Departamento de Ciencias; Matemáticas y Aplicaciones
Mesh segmentation and parameterization are crucial for Reverse Engineering (RE). Bijective parameterizations of the sub-meshes are a sine-qua-non test for segmentation. Current segmentation methods use either (1) topologic or (2) geometric criteria to partition the mesh. Reported topology-based segmentations produce large sub-meshes which reject parameterizations. Geometry-based segmentations are very sensitive to local variations in dihedral angle or curvatures, thus producing an exaggerated large number of small sub-meshes. Although small sub-meshes accept nearly isometric parameterizations, this significant granulation defeats the intent of synthesizing a usable Boundary Representation (compulsory for RE). In response to these limitations, this article presents an implementation of a hybrid geometry / topology segmentation algorithm for mechanical workpieces. This method locates heat transfer constraints (topological criterion) in low frequency neighborhoods of the mesh (geometric criterion) and solves for the resulting temperature distribution on the mesh. The mesh partition dictated by the temperature scalar map results in large, albeit parameterizable, sub-meshes. Our algorithm is tested with both benchmark repository and physical piece scans data. The experiments are successful, except for the well - known cases of topological cylinders, which require a user - introduced boundary along the cylinder generatrices. © 2018 Elsevier Ltd
Modeling and simulation of an Underwater Remotely Operated Vehicle (ROV) for surveillance and inspection of port facilities using CFD tools
(2008-01-01) Valencia, R.A.; Ramírez, J.A.; Gutiérrez, L.B.; García, M.J.; Valencia, R.A.; Ramírez, J.A.; Gutiérrez, L.B.; García, M.J.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica Aplicada
This article presents theoretical and computational studies with Computational Fluids Dynamics (CFD) tools of an Underwater Remotely Operated Vehicle (ROV), required to obtain reliable visual information, used for surveillance and maintenance of ship shells and underwater structures of Colombian port facilities. The thrust force is analyzed at the operational conditions by using CFD tools (FLUENT™, CFX™, COSMOSFLOW™) and the information about forces, torques and power of the vehicle's thrusters is obtained. The commercial propellers were modeled by using a reverse engineering process with a 3D scanner and Computer Aided Design (CAD) software (RAPIDFORM™). The results obtained with the CFD package allowed to evaluate several operating scenarios of the vehicle that are used for feedback purposes in the design process of the ROV before it be manufactured. Copyright © 2008 by ASME.
Multirate control of an unmanned aerial vehicle
(World Scientific and Engineering Academy and Society (WSEAS) Press, 2005-01-01) Vélez S., C.M.; Agudelo, A.; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
The application of multirate sampling to the control of an unmanned aerial vehicle (a mini-helicopter robot) using CACSD tools, developed specially for that goal, is presented. Multirate control is tested via simulation over the Matlab/Simulink mini-helicopter model, which is briefly described. A multirate modeling method is presented, which is the base of a CACSD tool for the modeling, simulation and real-time code generation of multirate control systems - the Multirate Control Toolbox (MCT).
Statistical analysis of the parameters in SPIF/DPIF in the thickness reduction in an experimental geometry
(Inderscience Publishers, 2019-01-01) Giraldo-Castrillon F.-A.; Giraldo-Castrillon Y.-M.; Páramo-Bermúdez G.-J.; Giraldo-Castrillon F.-A.; Giraldo-Castrillon Y.-M.; Páramo-Bermúdez G.-J.; Universidad EAFIT. Departamento de Ingeniería de Producción; Grupo en Tecnologías para la Producción
The objective of the present study was to determine the thickness reduction during the incremental deformation process with two techniques: SPIF/DPIF. A geometric structure was built using software computer-aided design (CAD) and the paths simulated in software computer-aided manufacturing (CAM). Experimental design of a full factorial type was made 23, for each technique, eight simulations, and three replicas. The variables studied in each experiment were the wall angle, the depth increase and the diameter of the tool. The three parameters are associated with the incremental deformation, although the angle was the most influential and the interaction between them in both techniques was significant. There was no difference in the comparative analysis between the different points in which the reduction of the thickness measured, just as neither one technique showed to be superior to the other. The angle of 68°, the depth of 1.0707 mm and the diameter of 9.3737 mm produced the least deformation with the SPIF technique and the angle of 60°, the depth of 1.2 mm and the diameter of 8 mm produced the least deformation with DPIF. © 2019 Inderscience Enterprises Ltd.
Structural optimization of as-built parts using reverse engineering and evolution strategies
(SPRINGER, 2008-06-01) García, M.J.; Boulanger, P.; Henao, M.; García, M.J.; Boulanger, P.; Henao, M.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica Aplicada
In industry, some parts are prone to failures or their design is simply sub-optimal. In those critical situations, one would like to be able to make changes to the part, making it lighter or improving its mechanical resistance. The problem of as-built parts is that the original computer-aided design (CAD) model is not available or is lost. To optimize them, a reverse engineering process is necessary to capture the shape and topology of the original design. This paper describes how to capture the original design geometry using a semi-automated reverse engineering process based on measurement provided by an optical 3D sensor. Following this reverse engineering process, a Fixed Grid Finite Element method and evolutionary algorithms are used to find the optimum shape that will minimize stress and weight. Several examples of industrial parts are presented. These examples show the advantages and disadvantages of the proposed method in an industrial scenario. © 2007 Springer-Verlag Berlin Heidelberg.

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