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Professor Oscar Ruiz was born in Tunja, Colombia. He obtained B.Sc. degrees in Mechanical Eng. (1983) and Computer Science (1987) at Los Andes University, Bogota, Colombia, a M.Sc. degree with emphasis in CAM (1991) and a Ph.D. with emphasis in CAD (1995) from the Mechanical & Industrial Eng. Dept. of University of Illinois at Urbana- Champaign, USA. Dr. Ruiz has held Visiting Researcher positions at Ford Motor Co. (Dearborn, USA. 1993 and 1995), Fraunhofer Inst. Graphische Datenverarbeitung (Darsmstad, Germany 1999 and 2001), University of Vigo (1999 and 2002), Max Planck Institute for Informatik (2004) and Purdue University (2009). In 1996 Dr. Ruiz was appointed as Faculty of the Mechanical Eng. and Computer Science Depts. at EAFIT University, Medellin, Colombia, and has been ever since the Coordinator of the Laboratory for interdisciplinary Research on CAD / CAM / CAE. Dr. Ruiz’ interests are Computer Aided Geometric Design, Geometric Reasoning and Applied Computational Geometry.
Avoidance of over-deposition at trajectory corners is relevant in Laser Metal Deposition (LMD) for Additive Manufacturing. Currently available LMD hardware only allows constant material feed (g/s). Therefore, gliding speed of the material dispenser is the remaining tuning variable for controlling metal over-deposition at corners. Existing literature reports trial-error physical experiments, addressing only particular corner angles. In response, this manuscript reports the implementation of a voxel-based simulator of the bead geometry, taking into consideration bead profile, dispenser velocity, material feed, and bead curve geometry. We use it to evaluate two constant-feed tailored-velocity strategies for minimizing material over-deposition at corners.
Diego Montoya-Zapata; Carles Creus; Aitor Moreno; Igor Ortiz; Piera Alvarez; Oscar Ruiz-Salguero; Jorge Posada. Computational minimization of over-deposition at corners of trajectories in Laser Metal Deposition. Manufacturing Letters 2021, 29, 29 -33.
AMA StyleDiego Montoya-Zapata, Carles Creus, Aitor Moreno, Igor Ortiz, Piera Alvarez, Oscar Ruiz-Salguero, Jorge Posada. Computational minimization of over-deposition at corners of trajectories in Laser Metal Deposition. Manufacturing Letters. 2021; 29 ():29-33.
Chicago/Turabian StyleDiego Montoya-Zapata; Carles Creus; Aitor Moreno; Igor Ortiz; Piera Alvarez; Oscar Ruiz-Salguero; Jorge Posada. 2021. "Computational minimization of over-deposition at corners of trajectories in Laser Metal Deposition." Manufacturing Letters 29, no. : 29-33.
In the context of generation of lubrication flows, gear pumps are widely used, with gerotor-type pumps being specially popular, given their low cost, high compactness, and reliability. The design process of gerotor pumps requires the simulation of the fluid dynamics phenomena that characterize the fluid displacement by the pump. Designers and researchers mainly rely on these methods: (i) computational fluid dynamics (CFD) and (ii) lumped parameter models. CFD methods are accurate in predicting the behavior of the pump, at the expense of large computing resources and time. On the other hand, Lumped Parameter models are fast and they do not require CFD software, at the expense of diminished accuracy. Usually, Lumped Parameter fluid simulation is mounted on specialized black-box visual programming platforms. The resulting pressures and flow rates are then fed to the design software. In response to the current status, this manuscript reports a virtual prototype to be used in the context of a Digital Twin tool. Our approach: (1) integrates pump design, fast approximate simulation, and result visualization processes, (2) does not require an external numerical solver platforms for the approximate model, (3) allows for the fast simulation of gerotor performance using sensor data to feed the simulation model, and (4) compares simulated data vs. imported gerotor operational data. Our results show good agreement between our prediction and CFD-based simulations of the actual pump. Future work is required in predicting rotor micro-movements and cavitation effects, as well as further integration of the physical pump with the software tool.
Juan Pareja-Corcho; Aitor Moreno; Bruno Simoes; Asier Pedrera-Busselo; Ekain San-Jose; Oscar Ruiz-Salguero; Jorge Posada. A Virtual Prototype for Fast Design and Visualization of Gerotor Pumps. Applied Sciences 2021, 11, 1190 .
AMA StyleJuan Pareja-Corcho, Aitor Moreno, Bruno Simoes, Asier Pedrera-Busselo, Ekain San-Jose, Oscar Ruiz-Salguero, Jorge Posada. A Virtual Prototype for Fast Design and Visualization of Gerotor Pumps. Applied Sciences. 2021; 11 (3):1190.
Chicago/Turabian StyleJuan Pareja-Corcho; Aitor Moreno; Bruno Simoes; Asier Pedrera-Busselo; Ekain San-Jose; Oscar Ruiz-Salguero; Jorge Posada. 2021. "A Virtual Prototype for Fast Design and Visualization of Gerotor Pumps." Applied Sciences 11, no. 3: 1190.
In the context of CAD CAM CAE (Computer-Aided Design, Manufacturing and Engineering) and Additive Manufacturing, the computation of level sets of closed 2-manifold triangular meshes (mesh slicing) is relevant for the generation of 3D printing patterns. Current slicing methods rely on the assumption that the function used to compute the level sets satisfies strong Morse conditions, rendering incorrect results when such a function is not a Morse one. To overcome this limitation, this manuscript presents an algorithm for the computation of mesh level sets under the presence of non-Morse degeneracies. To accomplish this, our method defines weak-Morse conditions, and presents a characterization of the possible types of degeneracies. This classification relies on the position of vertices, edges and faces in the neighborhood outside of the slicing plane. Finally, our algorithm produces oriented 1-manifold contours. Each contour orientation defines whether it belongs to a hole or to an external border. This definition is central for Additive Manufacturing purposes. We set up tests encompassing all known non-Morse degeneracies. Our algorithm successfully processes every generated case. Ongoing work addresses (a) a theoretical proof of completeness for our algorithm, (b) implementation of interval trees to improve the algorithm efficiency and, (c) integration into an Additive Manufacturing framework for industry applications.
Daniel Mejia-Parra; Oscar Ruiz-Salguero; Carlos Cadavid; Aitor Moreno; Jorge Posada. Level Sets of Weak-Morse Functions for Triangular Mesh Slicing. Mathematics 2020, 8, 1624 .
AMA StyleDaniel Mejia-Parra, Oscar Ruiz-Salguero, Carlos Cadavid, Aitor Moreno, Jorge Posada. Level Sets of Weak-Morse Functions for Triangular Mesh Slicing. Mathematics. 2020; 8 (9):1624.
Chicago/Turabian StyleDaniel Mejia-Parra; Oscar Ruiz-Salguero; Carlos Cadavid; Aitor Moreno; Jorge Posada. 2020. "Level Sets of Weak-Morse Functions for Triangular Mesh Slicing." Mathematics 8, no. 9: 1624.
Feature Recognition (FR) in Computer-aided Design (CAD) models is central for Design and Manufacturing. FR is a problem whose computational burden is intractable (NP-hard), given that its underlying task is the detection of graph isomorphism. Until now, compromises have been reached by only using FACE-based geometric information of prismatic CAD models to prune the search domain. Responding to such shortcomings, this manuscript presents an interactive FR method that more aggressively prunes the search space with reconfigurable geometric tests. Unlike previous approaches, our reconfigurable FR addresses curved EDGEs and FACEs. This reconfigurable approach allows enforcing arbitrary confluent topologic and geometric filters, thus handling an expanded scope. The test sequence is itself a graph (i.e., not a linear or total-order sequence). Unlike the existing methods that are FACE-based, the present one permits combinations of topologies whose dimensions are two (SHELL or FACE), one (LOOP or EDGE), or 0 (VERTEX). This system has been implemented in an industrial environment, using icon graphs for the interactive rule configuration. The industrial instancing allows industry based customization and itis faster when compared to topology-based feature recognition. Future work is required in improving the robustness of search conditions, treating the problem of interacting or nested features, and improving the graphic input interface.
Juan Pareja-Corcho; Oscar Betancur-Acosta; Jorge Posada; Antonio Tammaro; Oscar Ruiz-Salguero; Carlos Cadavid. Reconfigurable 3D CAD Feature Recognition Supporting Confluent n-Dimensional Topologies and Geometric Filters for Prismatic and Curved Models. Mathematics 2020, 8, 1356 .
AMA StyleJuan Pareja-Corcho, Oscar Betancur-Acosta, Jorge Posada, Antonio Tammaro, Oscar Ruiz-Salguero, Carlos Cadavid. Reconfigurable 3D CAD Feature Recognition Supporting Confluent n-Dimensional Topologies and Geometric Filters for Prismatic and Curved Models. Mathematics. 2020; 8 (8):1356.
Chicago/Turabian StyleJuan Pareja-Corcho; Oscar Betancur-Acosta; Jorge Posada; Antonio Tammaro; Oscar Ruiz-Salguero; Carlos Cadavid. 2020. "Reconfigurable 3D CAD Feature Recognition Supporting Confluent n-Dimensional Topologies and Geometric Filters for Prismatic and Curved Models." Mathematics 8, no. 8: 1356.
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.
Diego Montoya-Zapata; Diego A. Acosta; Camilo Cortés; Juan Pareja-Corcho; Aitor Moreno; Jorge Posada; Oscar Ruiz-Salguero. Approximation of the Mechanical Response of Large Lattice Domains Using Homogenization and Design of Experiments. Applied Sciences 2020, 10, 3858 .
AMA StyleDiego Montoya-Zapata, Diego A. Acosta, Camilo Cortés, Juan Pareja-Corcho, Aitor Moreno, Jorge Posada, Oscar Ruiz-Salguero. Approximation of the Mechanical Response of Large Lattice Domains Using Homogenization and Design of Experiments. Applied Sciences. 2020; 10 (11):3858.
Chicago/Turabian StyleDiego Montoya-Zapata; Diego A. Acosta; Camilo Cortés; Juan Pareja-Corcho; Aitor Moreno; Jorge Posada; Oscar Ruiz-Salguero. 2020. "Approximation of the Mechanical Response of Large Lattice Domains Using Homogenization and Design of Experiments." Applied Sciences 10, no. 11: 3858.
In flexible manufacturing systems, fast feedback from simulation solutions is required for effective tool path planning and parameter optimization. In the particular sub-domain of laser heating/cutting of thin rectangular plates, current state-of-the-art methods include frequency-domain (spectral) analytic solutions that greatly reduce the required computational time in comparison to industry standard finite element based approaches. However, these spectral solutions have not been presented previously in terms of Fourier methods and Fast Fourier Transform (FFT) implementations. This manuscript presents four different schemes that translate the problem of laser heating of rectangular plates into equivalent FFT problems. The presented schemes make use of the FFT algorithm to reduce the computational time complexity of the problem from O ( M 2 N 2 ) to O ( M N log ( M N ) ) (with M × N being the discretization size of the plate). The test results show that the implemented schemes outperform previous non-FFT approaches both in CPU and GPU hardware, resulting in 100 × faster runs. Future work addresses thermal/stress analysis, non-rectangular geometries and non-linear interactions (such as material melting/ablation, convection and radiation heat transfer).
Daniel Mejia-Parra; Ander Arbelaiz; Oscar Ruiz-Salguero; Juan Lalinde-Pulido; Aitor Moreno; Jorge Posada. Fast Simulation of Laser Heating Processes on Thin Metal Plates with FFT Using CPU/GPU Hardware. Applied Sciences 2020, 10, 3281 .
AMA StyleDaniel Mejia-Parra, Ander Arbelaiz, Oscar Ruiz-Salguero, Juan Lalinde-Pulido, Aitor Moreno, Jorge Posada. Fast Simulation of Laser Heating Processes on Thin Metal Plates with FFT Using CPU/GPU Hardware. Applied Sciences. 2020; 10 (9):3281.
Chicago/Turabian StyleDaniel Mejia-Parra; Ander Arbelaiz; Oscar Ruiz-Salguero; Juan Lalinde-Pulido; Aitor Moreno; Jorge Posada. 2020. "Fast Simulation of Laser Heating Processes on Thin Metal Plates with FFT Using CPU/GPU Hardware." Applied Sciences 10, no. 9: 3281.
In the context of lattice-based design and manufacturing, the problem of physical realization of density maps into lattices of a particular family is central. Density maps are prescribed by design optimization algorithms, which seek to fulfill structural demands on a workpiece, while saving material. These density maps cannot be directly manufactured since local graded densities cannot be achieved using the bulk solid material. Because of this reason, existing topology optimization approaches bias the local voxel relative density to either 0 (void) or 1 (filled). Additive manufacturing opens possibilities to produce graded density individuals belonging to different lattice families. However, voxel-level sampled boundary representations of the individuals produce rough and possibly disconnected shells. In response to this limitation, this article uses sub-voxel sampling (largely unexploited in the literature) to generate lattices of graded densities. This sub-voxel sampling eliminates the risk of shell disconnections and renders better surface continuity. The manuscript devises a function to produce Schwarz cells that materialize a given relative density. This article illustrates a correlation of continuity against stress concentration by simulating C 0 and C 1 inter-lattice continuity. The implemented algorithm produces implicit functions and thus lattice designs which are suitable for metal additive manufacturing and able to achieve the target material savings. The resulting workpieces, produced by outsource manufacturers, are presented. Additional work is required in the modeling of the mechanical response (stress/strain/deformation) and response of large lattice sets (with arbitrary geometry and topology) under working loads.
Diego Montoya-Zapata; Aitor Moreno; Juan Pareja-Corcho; Jorge Posada; Oscar Ruiz-Salguero. Density-Sensitive Implicit Functions Using Sub-Voxel Sampling in Additive Manufacturing. Metals 2019, 9, 1293 .
AMA StyleDiego Montoya-Zapata, Aitor Moreno, Juan Pareja-Corcho, Jorge Posada, Oscar Ruiz-Salguero. Density-Sensitive Implicit Functions Using Sub-Voxel Sampling in Additive Manufacturing. Metals. 2019; 9 (12):1293.
Chicago/Turabian StyleDiego Montoya-Zapata; Aitor Moreno; Juan Pareja-Corcho; Jorge Posada; Oscar Ruiz-Salguero. 2019. "Density-Sensitive Implicit Functions Using Sub-Voxel Sampling in Additive Manufacturing." Metals 9, no. 12: 1293.
Diego Montoya-Zapata; Camilo Cortés; Oscar Ruiz-Salguero. FE-simulations with a simplified model for open-cell porous materials: A Kelvin cell approach. Journal of Computational Methods in Sciences and Engineering 2019, 19, 989 -1000.
AMA StyleDiego Montoya-Zapata, Camilo Cortés, Oscar Ruiz-Salguero. FE-simulations with a simplified model for open-cell porous materials: A Kelvin cell approach. Journal of Computational Methods in Sciences and Engineering. 2019; 19 (4):989-1000.
Chicago/Turabian StyleDiego Montoya-Zapata; Camilo Cortés; Oscar Ruiz-Salguero. 2019. "FE-simulations with a simplified model for open-cell porous materials: A Kelvin cell approach." Journal of Computational Methods in Sciences and Engineering 19, no. 4: 989-1000.
In the context of CAD, CAM, CAE, and reverse engineering, the problem of mesh parameterization is a central process. Mesh parameterization implies the computation of a bijective map ϕ from the original mesh M∈R3 to the planar domain ϕ(M)∈R2. The mapping may preserve angles, areas, or distances. Distance-preserving parameterizations (i.e., isometries) are obviously attractive. However, geodesic-based isometries present limitations when the mesh has concave or disconnected boundary (i.e., holes). Recent advances in computing geodesic maps using the heat equation in 2-manifolds motivate us to revisit mesh parameterization with geodesic maps. We devise a Poisson surface underlying, extending, and filling the holes of the mesh M. We compute a near-isometric mapping for quasi-developable meshes by using geodesic maps based on heat propagation. Our method: (1) Precomputes a set of temperature maps (heat kernels) on the mesh; (2) estimates the geodesic distances along the piecewise linear surface by using the temperature maps; and (3) uses multidimensional scaling (MDS) to acquire the 2D coordinates that minimize the difference between geodesic distances on M and Euclidean distances on R2. This novel heat-geodesic parameterization is successfully tested with several concave and/or punctured surfaces, obtaining bijective low-distortion parameterizations. Failures are registered in nonsegmented, highly nondevelopable meshes (such as seam meshes). These cases are the goal of future endeavors.
Daniel Mejia-Parra; Jairo R. Sánchez; Jorge Posada; Oscar Ruiz-Salguero; Carlos Cadavid. Quasi-Isometric Mesh Parameterization Using Heat-Based Geodesics and Poisson Surface Fills. Mathematics 2019, 7, 753 .
AMA StyleDaniel Mejia-Parra, Jairo R. Sánchez, Jorge Posada, Oscar Ruiz-Salguero, Carlos Cadavid. Quasi-Isometric Mesh Parameterization Using Heat-Based Geodesics and Poisson Surface Fills. Mathematics. 2019; 7 (8):753.
Chicago/Turabian StyleDaniel Mejia-Parra; Jairo R. Sánchez; Jorge Posada; Oscar Ruiz-Salguero; Carlos Cadavid. 2019. "Quasi-Isometric Mesh Parameterization Using Heat-Based Geodesics and Poisson Surface Fills." Mathematics 7, no. 8: 753.
In the context of Computer Simulation, the problem of heat transfer analysis of thin plate laser heating is relevant for downstream simulations of machining processes. Alternatives to address the problem include (i) numerical methods, which require unaffordable time and storage computing resources even for very small domains, (ii) analytical methods, which are less expensive but are limited to simple geometries, straight trajectories and do not account for material non-linearities or convective cooling. This manuscript presents a parallel efficient analytic method to determine, in a thin plate under convective cooling, the transient temperature field resulting from application of a laser spot following a curved trajectory. Convergence of both FEA (Finite Element Analysis) and the analytic approaches for a small planar plate is presented, estimating a maximum relative error for the analytic approach below 3.5% at the laser spot. Measured computing times evidence superior efficiency of the analytic approach w.r.t. FEA. A study case, with the analytic solution, for a large spatial and time domain (1m×1m and 12s history, respectively) is presented. This case is not tractable with FEA, where domains larger than 0.05m×0.05m and 2s require high amounts of computing time and storage.
Daniel Mejia-Parra; Aitor Moreno; Jorge Posada; Oscar Ruiz-Salguero; Iñigo Barandiaran; Juan Carlos Poza; Raúl Chopitea. Frequency-domain analytic method for efficient thermal simulation under curved trajectories laser heating. Mathematics and Computers in Simulation 2019, 166, 177 -192.
AMA StyleDaniel Mejia-Parra, Aitor Moreno, Jorge Posada, Oscar Ruiz-Salguero, Iñigo Barandiaran, Juan Carlos Poza, Raúl Chopitea. Frequency-domain analytic method for efficient thermal simulation under curved trajectories laser heating. Mathematics and Computers in Simulation. 2019; 166 ():177-192.
Chicago/Turabian StyleDaniel Mejia-Parra; Aitor Moreno; Jorge Posada; Oscar Ruiz-Salguero; Iñigo Barandiaran; Juan Carlos Poza; Raúl Chopitea. 2019. "Frequency-domain analytic method for efficient thermal simulation under curved trajectories laser heating." Mathematics and Computers in Simulation 166, no. : 177-192.
Industrial dimensional assessment presents instances in which early control is exerted among “warm” (approx. 600 ∘C) pieces. Early control saves resources, as defective processes are timely stopped and corrected. Existing literature is devoid of dimensional assessment on warm workpieces. In response to this absence, this manuscript presents the implementation and results of an optical system which performs in-line dimensional inspection of revolution warm workpieces singled out from the (forming) process. Our system can automatically measure, in less than 60 s, the circular runout of warm revolution workpieces. Such a delay would be 20 times longer if cool-downs were required. Off-line comparison of the runout of T-temperature workpieces (27 ∘C ≤ T ≤ 560 ∘C) shows a maximum difference of 0.1 mm with respect to standard CMM (Coordinate Measurement Machine) runout of cold workpieces (27 ∘C), for workpieces as long as 160 mm. Such a difference is acceptable for the forging process in which the system is deployed. The test results show no correlation between the temperature and the runout of the workpiece at such level of uncertainty. A prior-to-operation Analysis of Variance (ANOVA) test validates the repeatability and reproducibility (R&R) of our measurement system. In-line assessment of warm workpieces fills a gap in manufacturing processes where early detection of dimensional misfits compensates for the precision loss of the vision system. The integrated in-line system reduces the number of defective workpieces by 95 % .
Daniel Mejia-Parra; Jairo R. Sánchez; Oscar Ruiz-Salguero; Marcos Alonso; Alberto Izaguirre; Erik Gil; Jorge Palomar; Jorge Posada; Marcos Alonso. In-Line Dimensional Inspection of Warm-Die Forged Revolution Workpieces Using 3D Mesh Reconstruction. Applied Sciences 2019, 9, 1069 .
AMA StyleDaniel Mejia-Parra, Jairo R. Sánchez, Oscar Ruiz-Salguero, Marcos Alonso, Alberto Izaguirre, Erik Gil, Jorge Palomar, Jorge Posada, Marcos Alonso. In-Line Dimensional Inspection of Warm-Die Forged Revolution Workpieces Using 3D Mesh Reconstruction. Applied Sciences. 2019; 9 (6):1069.
Chicago/Turabian StyleDaniel Mejia-Parra; Jairo R. Sánchez; Oscar Ruiz-Salguero; Marcos Alonso; Alberto Izaguirre; Erik Gil; Jorge Palomar; Jorge Posada; Marcos Alonso. 2019. "In-Line Dimensional Inspection of Warm-Die Forged Revolution Workpieces Using 3D Mesh Reconstruction." Applied Sciences 9, no. 6: 1069.
Cristian C. Rendon; Colombia UniversidadEAFIT; José L. Hernandez; Oscar Ruiz-Salguero. Wing profile evolution driven by computational fluid dynamics. Revista UIS Ingenierías 2019, 18, 139 -146.
AMA StyleCristian C. Rendon, Colombia UniversidadEAFIT, José L. Hernandez, Oscar Ruiz-Salguero. Wing profile evolution driven by computational fluid dynamics. Revista UIS Ingenierías. 2019; 18 (2):139-146.
Chicago/Turabian StyleCristian C. Rendon; Colombia UniversidadEAFIT; José L. Hernandez; Oscar Ruiz-Salguero. 2019. "Wing profile evolution driven by computational fluid dynamics." Revista UIS Ingenierías 18, no. 2: 139-146.
Diego Montoya-Zapata; Diego A. Acosta; Oscar Ruiz-Salguero; Jorge Posada; David Sanchez-Londono. A General Meta-graph Strategy for Shape Evolution under Mechanical Stress. Cybernetics and Systems 2019, 50, 3 -24.
AMA StyleDiego Montoya-Zapata, Diego A. Acosta, Oscar Ruiz-Salguero, Jorge Posada, David Sanchez-Londono. A General Meta-graph Strategy for Shape Evolution under Mechanical Stress. Cybernetics and Systems. 2019; 50 (1):3-24.
Chicago/Turabian StyleDiego Montoya-Zapata; Diego A. Acosta; Oscar Ruiz-Salguero; Jorge Posada; David Sanchez-Londono. 2019. "A General Meta-graph Strategy for Shape Evolution under Mechanical Stress." Cybernetics and Systems 50, no. 1: 3-24.
Interactive multi-beam laser machining simulation is crucial in the context of tool path planning and optimization of laser machining parameters. Current simulation approaches for heat transfer analysis (1) rely on numerical Finite Element methods (or any of its variants), non-suitable for interactive applications; and (2) require the multiple laser beams to be completely synchronized in trajectories, parameters and time frames. To overcome this limitation, this manuscript presents an algorithm for interactive simulation of the transient temperature field on the sheet metal. Contrary to standard numerical methods, our algorithm is based on an analytic solution in the frequency domain, allowing arbitrary time/space discretizations without loss of precision and non-monotonic retrieval of the temperature history. In addition, the method allows complete asynchronous laser beams with independent trajectories, parameters and time frames. Our implementation in a GPU device allows simulations at interactive rates even for a large amount of simultaneous laser beams. The presented method is already integrated into an interactive simulation environment for sheet cutting. Ongoing work addresses thermal stress coupling and laser ablation.
Daniel Mejia-Parra; Diego Montoya-Zapata; Ander Arbelaiz; Aitor Moreno; Jorge Posada; Oscar Ruiz-Salguero. Fast Analytic Simulation for Multi-Laser Heating of Sheet Metal in GPU. Materials 2018, 11, 2078 .
AMA StyleDaniel Mejia-Parra, Diego Montoya-Zapata, Ander Arbelaiz, Aitor Moreno, Jorge Posada, Oscar Ruiz-Salguero. Fast Analytic Simulation for Multi-Laser Heating of Sheet Metal in GPU. Materials. 2018; 11 (11):2078.
Chicago/Turabian StyleDaniel Mejia-Parra; Diego Montoya-Zapata; Ander Arbelaiz; Aitor Moreno; Jorge Posada; Oscar Ruiz-Salguero. 2018. "Fast Analytic Simulation for Multi-Laser Heating of Sheet Metal in GPU." Materials 11, no. 11: 2078.
Evolutionary Structural Optimization (ESO) seeks to mimic the form in which nature designs shapes. This paper focuses on shape carving triggered by environmental stimuli. In this realm, existing algorithms delete under - stressed parts of a basic shape, until a reasonably efficient (under some criterion) shape emerges. In the present article, we state a generalization of such approaches in two forms: (1) We use a formalism that enables stimuli from different sources, in addition to stress ones (e.g. kinematic constraints, friction, abrasion). (2) We use metagraphs built on the Finite Element constraint graphs to eliminate the dependency of the evolution on the particular neighborhood chosen to be deleted in a given iteration. The proposed methodology emulates 2D landmark cases of ESO. Future work addresses the implementation of such stimuli type, the integration of our algorithm with evolutionary based techniques and the extension of the method to 3D shapes.
Diego Montoya-Zapata; Diego Acosta; Oscar Ruiz-Salguero; David Sanchez-Londono. FEA Structural Optimization Based on Metagraphs. Advances in Intelligent Systems and Computing 2018, 209 -220.
AMA StyleDiego Montoya-Zapata, Diego Acosta, Oscar Ruiz-Salguero, David Sanchez-Londono. FEA Structural Optimization Based on Metagraphs. Advances in Intelligent Systems and Computing. 2018; ():209-220.
Chicago/Turabian StyleDiego Montoya-Zapata; Diego Acosta; Oscar Ruiz-Salguero; David Sanchez-Londono. 2018. "FEA Structural Optimization Based on Metagraphs." Advances in Intelligent Systems and Computing , no. : 209-220.
Daniel Mejía; Oscar Ruiz-Salguero; Jairo R. Sánchez; Jorge Posada; Aitor Moreno; Carlos A. Cadavid. Hybrid geometry / topology based mesh segmentation for reverse engineering. Computers & Graphics 2018, 73, 47 -58.
AMA StyleDaniel Mejía, Oscar Ruiz-Salguero, Jairo R. Sánchez, Jorge Posada, Aitor Moreno, Carlos A. Cadavid. Hybrid geometry / topology based mesh segmentation for reverse engineering. Computers & Graphics. 2018; 73 ():47-58.
Chicago/Turabian StyleDaniel Mejía; Oscar Ruiz-Salguero; Jairo R. Sánchez; Jorge Posada; Aitor Moreno; Carlos A. Cadavid. 2018. "Hybrid geometry / topology based mesh segmentation for reverse engineering." Computers & Graphics 73, no. : 47-58.
Estimation 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.
Camilo Cortés; Maria Osorno; David Uribe; Holger Steeb; Oscar Ruiz-Salguero; Iñigo Barandiarán; Julián Flórez. Geometry simplification of open-cell porous materials for elastic deformation FEA. Engineering with Computers 2018, 35, 257 -276.
AMA StyleCamilo Cortés, Maria Osorno, David Uribe, Holger Steeb, Oscar Ruiz-Salguero, Iñigo Barandiarán, Julián Flórez. Geometry simplification of open-cell porous materials for elastic deformation FEA. Engineering with Computers. 2018; 35 (1):257-276.
Chicago/Turabian StyleCamilo Cortés; Maria Osorno; David Uribe; Holger Steeb; Oscar Ruiz-Salguero; Iñigo Barandiarán; Julián Flórez. 2018. "Geometry simplification of open-cell porous materials for elastic deformation FEA." Engineering with Computers 35, no. 1: 257-276.
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%.
Daniel Mejia; Aitor Moreno; Ander Arbelaiz; Jorge Posada; Oscar E. Ruiz-Salguero; Raúl Chopitea. Accelerated Thermal Simulation for Three-Dimensional Interactive Optimization of Computer Numeric Control Sheet Metal Laser Cutting. Journal of Manufacturing Science and Engineering 2017, 140, 1 .
AMA StyleDaniel Mejia, Aitor Moreno, Ander Arbelaiz, Jorge Posada, Oscar E. Ruiz-Salguero, Raúl Chopitea. Accelerated Thermal Simulation for Three-Dimensional Interactive Optimization of Computer Numeric Control Sheet Metal Laser Cutting. Journal of Manufacturing Science and Engineering. 2017; 140 (3):1.
Chicago/Turabian StyleDaniel Mejia; Aitor Moreno; Ander Arbelaiz; Jorge Posada; Oscar E. Ruiz-Salguero; Raúl Chopitea. 2017. "Accelerated Thermal Simulation for Three-Dimensional Interactive Optimization of Computer Numeric Control Sheet Metal Laser Cutting." Journal of Manufacturing Science and Engineering 140, no. 3: 1.
PurposeMesh Parameterization is central to reverse engineering, tool path planning, etc. This work synthesizes parameterizations with (a) un-constrained borders, (b) overall minimum angle plus (c) area distortion. We present an assessment of the sensitivity of the minimized distortion with respect to weighed area and angle distortions.Design/methodology/approachA mesh parameterization is implemented which does not constrain borders by performing: (1) isometry maps for each triangle to the plane Z=0, (2) An affine transform within the plane Z=0 to glue the triangles back together and (3) a Levenberg-Marquardt minimization algorithm of a nonlinear F penalty function that modifies the parameters of the transformations (1) and (2) to discourage triangle flips, angle or area distortions. F is a convex weighed combination of area distortion (weight: α with 0≤α≤1) and angle distortion (weight: 1-α).FindingsOur parameterization algorithm has linear complexity (O(n), n= number of mesh vertices). The sensitivity analysis permits a fine-tuning of the weight parameter (α) which achieves overall bijective parameterizations in the studied cases. No theoretical guarantee is given in this manuscript for the bijectivity. Our algorithm has equal or superior performance compared with the ABF, LSCM and ARAP algorithms for the Ball, Cow and Gargoyle datasets. Additional correct results of our algorithm alone are presented for the Foot, Fandisk and Sliced-Glove datasets.Originality/value(1) The devised free boundary nonlinear mesh parameterization method does not require a valid initial parameterization and produces locally bijective parameterizations in all of our tests. (2) A formal sensitivity analysis shows that the resulting parameterization is more stable (i.e. the UV mapping changes very little) when the algorithm tries to preserve angles than when it tries to preserve areas. (3) Our algorithm belongs to the class that parameterizes meshes with holes. (4) We present the results of a complexity analysis comparing our algorithm with 12 competing ones.
Daniel Mejia; Diego A. Acosta; Oscar Ruiz-Salguero. Weighted area/angle distortion minimization for Mesh Parameterization. Engineering Computations 2017, 34, 1874 -1895.
AMA StyleDaniel Mejia, Diego A. Acosta, Oscar Ruiz-Salguero. Weighted area/angle distortion minimization for Mesh Parameterization. Engineering Computations. 2017; 34 (6):1874-1895.
Chicago/Turabian StyleDaniel Mejia; Diego A. Acosta; Oscar Ruiz-Salguero. 2017. "Weighted area/angle distortion minimization for Mesh Parameterization." Engineering Computations 34, no. 6: 1874-1895.
Stella Orozco; Arno Formella; Carlos A. Cadavid; Oscar Ruiz-Salguero; Maria Osorno. Geometry and Topology-based Segmentation of 2-Manifold Triangular Meshes in R3. British Journal of Applied Science & Technology 2017, 21, 1 -14.
AMA StyleStella Orozco, Arno Formella, Carlos A. Cadavid, Oscar Ruiz-Salguero, Maria Osorno. Geometry and Topology-based Segmentation of 2-Manifold Triangular Meshes in R3. British Journal of Applied Science & Technology. 2017; 21 (1):1-14.
Chicago/Turabian StyleStella Orozco; Arno Formella; Carlos A. Cadavid; Oscar Ruiz-Salguero; Maria Osorno. 2017. "Geometry and Topology-based Segmentation of 2-Manifold Triangular Meshes in R3." British Journal of Applied Science & Technology 21, no. 1: 1-14.