Examinando por Autor "García, M.J."

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    A comparative computational study of blood flow pattern in exemplary textile vascular grafts
    (Taylor and Francis Ltd., 2018-01-01) Valencia, R.A.; García, M.J.; Bustamante, J.; Mecánica Aplicada
    Textile vascular grafts are biomedical devices and play an important role serving as a solution for the partial replacement of damaged arterial vessels. It is believed that the success of a textile vascular graft, in the healing process after implantation, is due to the porous micro-structure of the wall. Although the transport of fluids through textiles is of great technical interest in biomedical applications, little is known about predicting the micro-flow pattern and cellular transport through the wall. The aim of this work is to investigate how the type of fabric, permeability and porosity affect both the local fluid dynamics at several scales and the fluid-particle interaction between platelets in textile grafts, related with the graft occlusion. This study involves both experimental and computational tests. Experimental tests are performed to characterize the permeability and porosity according to the ISO 7198 standard. The numerical process is based on a multi-scale approach where the fluid flow is solved with the Finite Element Method and the discrete particles are solved with the Molecular Dynamic Method. The results have shown that the type of fabric in textile vascular grafts and the degree of porosity and permeability affect both the local fluid dynamics and the level of penetration of platelets through the wall, thus indicating their importance as design parameters. © 2017 Informa UK Limited, trading as Taylor & Francis Group.
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    COMPLEX VARIABLE SENSITIVITY ANALYSIS OF THE RADIO FREQUENCY ABLATION PROCESS FOR CANCER TREATMENT
    (International Center for Numerical Methods in Engineering, 2015-01-01) Monsalvo, J.F.; García, M.J.; Monsalvo, J.F.; García, M.J.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica Aplicada
    The complex Taylor series expansion (CTSE) method is applied in the sensitivity analysis of radio frequency ablation (RFA) procedures, in which the temperature distribution has to be accurately predicted in order to apply proper temperature values to tumor tissue and to avoid unwanted damage of healthy one. For this reason. the CTSE method was used to calculate local sensitivity. In this work, we solve a basic 2D model of the RFA process modelled by the bioheat transfer equation, and coupled with Joule heating equation. The accuracy, robustness and step -size independence are the main advantages of the CTSE method.
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    Design, construction and testing of a data transmission system for a mid-power rocket model
    (IEEE Computer Society, 2017-01-01) Botero, A.Y.; Rodríguez, J.S.; Serna, J.G.; Gómez, A.; García, M.J.; Botero, A.Y.; Rodríguez, J.S.; Serna, J.G.; Gómez, A.; García, M.J.; Universidad EAFIT. Departamento de Ciencias; Modelado Matemático
    This paper presents the continuation of a previous work in the development of a communication module for a solid propellant mid-power rocket model named "Simple-1" mission. It considered the design, construction, and testing procedures related to the data transmission protocol and its data rate. The current phase considers the antenna's optimization, launching, and data analysis on-flight. In the actual optimization step, the antenna components were modified to increase the gain. A rocket model Estes Ventris Series Pro II® was used to carry in the payload section a communication module with several sensors in a CanSat form factor. The collected data was processed using an Arduino Mini micro-controller and transmitted using a radio module (Radiometrix) to a software defined radio (SDR) HackRF-based platform on the ground station. The printed circuit boards (PCBs) were designed and manufactured from commercial off the shelf (COTS) and assembled in a cylindrical rack structure similar to this small format satellite concept. The Simple-1 was tested with the help of a wind tunnel to validate the behavior of the antenna's subsystem and was proved in several launches using solid propellant motors reaching altitudes from 500-700 meters. Different experimental data such as altitude, position, atmospheric pressure, and vehicle temperature were successfully captured and analyzed. This demonstrates that it is possible to develop low cost near space activities, gradually installing capabilities in a teamwork. In this developing stage, the techniques to design and manufacture two layers PCB were appropriated by traditional circuit board etching methods. In addition, the SDR technology was studied and implemented for the telemetry architecture. The use of surface mounting devices (SMD) offers an alternative to reduce the volume of the module. In the future, it is expected to have more advances in the stability of the communication protocols, robust hardware manufacturing, and integration of electronic circuits in four-layer PCB, in order to contribute to the access to space in our region and local aerospace industry developments. © 2017 IEEE.
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    Design, construction and testing of a data transmission system for a mid-power rocket model
    (IEEE Computer Society, 2017-01-01) Botero, A.Y.; Rodríguez, J.S.; Serna, J.G.; Gómez, A.; García, M.J.; Botero, A.Y.; Rodríguez, J.S.; Serna, J.G.; Gómez, A.; García, M.J.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica Aplicada
    This paper presents the continuation of a previous work in the development of a communication module for a solid propellant mid-power rocket model named "Simple-1" mission. It considered the design, construction, and testing procedures related to the data transmission protocol and its data rate. The current phase considers the antenna's optimization, launching, and data analysis on-flight. In the actual optimization step, the antenna components were modified to increase the gain. A rocket model Estes Ventris Series Pro II® was used to carry in the payload section a communication module with several sensors in a CanSat form factor. The collected data was processed using an Arduino Mini micro-controller and transmitted using a radio module (Radiometrix) to a software defined radio (SDR) HackRF-based platform on the ground station. The printed circuit boards (PCBs) were designed and manufactured from commercial off the shelf (COTS) and assembled in a cylindrical rack structure similar to this small format satellite concept. The Simple-1 was tested with the help of a wind tunnel to validate the behavior of the antenna's subsystem and was proved in several launches using solid propellant motors reaching altitudes from 500-700 meters. Different experimental data such as altitude, position, atmospheric pressure, and vehicle temperature were successfully captured and analyzed. This demonstrates that it is possible to develop low cost near space activities, gradually installing capabilities in a teamwork. In this developing stage, the techniques to design and manufacture two layers PCB were appropriated by traditional circuit board etching methods. In addition, the SDR technology was studied and implemented for the telemetry architecture. The use of surface mounting devices (SMD) offers an alternative to reduce the volume of the module. In the future, it is expected to have more advances in the stability of the communication protocols, robust hardware manufacturing, and integration of electronic circuits in four-layer PCB, in order to contribute to the access to space in our region and local aerospace industry developments. © 2017 IEEE.
  • No hay miniatura disponible
    Ítem
    Design, construction and testing of a data transmission system for a mid-power rocket model
    (IEEE Computer Society, 2017-01-01) Botero, A.Y.; Rodríguez, J.S.; Serna, J.G.; Gómez, A.; García, M.J.; Botero, A.Y.; Rodríguez, J.S.; Serna, J.G.; Gómez, A.; García, M.J.; Universidad EAFIT. Departamento de Ciencias; Bioiversidad, Evolución y Conservación
    This paper presents the continuation of a previous work in the development of a communication module for a solid propellant mid-power rocket model named "Simple-1" mission. It considered the design, construction, and testing procedures related to the data transmission protocol and its data rate. The current phase considers the antenna's optimization, launching, and data analysis on-flight. In the actual optimization step, the antenna components were modified to increase the gain. A rocket model Estes Ventris Series Pro II® was used to carry in the payload section a communication module with several sensors in a CanSat form factor. The collected data was processed using an Arduino Mini micro-controller and transmitted using a radio module (Radiometrix) to a software defined radio (SDR) HackRF-based platform on the ground station. The printed circuit boards (PCBs) were designed and manufactured from commercial off the shelf (COTS) and assembled in a cylindrical rack structure similar to this small format satellite concept. The Simple-1 was tested with the help of a wind tunnel to validate the behavior of the antenna's subsystem and was proved in several launches using solid propellant motors reaching altitudes from 500-700 meters. Different experimental data such as altitude, position, atmospheric pressure, and vehicle temperature were successfully captured and analyzed. This demonstrates that it is possible to develop low cost near space activities, gradually installing capabilities in a teamwork. In this developing stage, the techniques to design and manufacture two layers PCB were appropriated by traditional circuit board etching methods. In addition, the SDR technology was studied and implemented for the telemetry architecture. The use of surface mounting devices (SMD) offers an alternative to reduce the volume of the module. In the future, it is expected to have more advances in the stability of the communication protocols, robust hardware manufacturing, and integration of electronic circuits in four-layer PCB, in order to contribute to the access to space in our region and local aerospace industry developments. © 2017 IEEE.
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    Ítem
    Engineering design using evolutionary structural optimisation based on iso-stress-driven smooth geometry removal
    (2001) García, M.J.; Ruíz, O.E.; Steven, G.P.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAE
    The main goal of Evolutionary Structural Optimisation (ESO) research has been to provide an easily applicable optimisation method for the engineering industry which assists the design process for product improvement -- Originally O was based on the concept of fully stressed structures and it is obtained by slowly removing, from a Finite Element mesh these elements that present the lowest stress value -- Following this heuristically-driven removal criteria, the initial topology evolves towards the optimum one -- Since its introduction in 1992, ESO has been developed and extended to several types of structural problems -- Initial weaknesses of ESO were (i) typically long solution times and (ii) topologies with jagged surfaces as a result of removing whole elements in the optimisation process -- These characteristics hindered its application to computer aided design and analysis -- In this investigation, these weaknesses have been addressed for 2D situations by (i) basing the stress computation on the Fixed Grid (FG) finite element method and (ii) removing material with the lowest values along iso-stress contours instead of removing whole elements -- A boundary representation (B-rep) of the structure is maintained at each iteration of the optimisation process -- Modification to the workpiece is made by identifying the stress contour lines and incorporating them into the evolving geometry -- The topological consistency of the B-rep is maintained via normalized 2D boolean operations
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    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.
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    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.