Examinando por Materia "Nanotechnology"
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Ítem Design of computer experiments applied to modeling of compliant mechanisms for real-time control(Springer London, 2013-07) Acosta, Diego A.; Restrepo, David; Durango, Sebastián; Ruíz, Óscar E.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis article discusses the use of design of computer experiments (DOCE) (i.e., experiments run with a computer model to find how a set of inputs affects a set of outputs) to obtain a force–displacement meta-model (i.e., a mathematical equation that summarizes and aids in analyz-ing the input–output data of a DOCE) of compliant mechanisms (CMs) -- The procedure discussed produces a force–displacement meta-model, or closed analytic vector function, that aims to control CMs in real-time -- In our work, the factorial and space-filling DOCE meta-model of CMs is supported by finite element analysis (FEA) -- The protocol discussed is used to model the HexFlex mechanism functioning under quasi-static conditions -- The HexFlex is a parallel CM for nano-manipulation that allows six degrees of freedom (x, y, z, hx, hy, hz) of its moving platform -- In the multi-linear model fit of the HexFlex, the products or inter-actions proved to be negligible, yielding a linear model (i.e.,linear in the inputs) for the operating range -- The accuracy of the meta-model was calculated by conducting a set of computer experiments with random uniform distribution of the input forces -- Three error criteria were recorded comparing the meta-model prediction with respect to the results of the FEA experiments by determining: (1) maximum of the absolute value of the error, (2) relative error, and (3) root mean square error -- The maximum errors of our model are lower than high-precision manufacturing tolerances and are also lower than those reported by other researchers who have tried to fit meta-models to the HexFlex mechanismÍtem Diseño y construcción de un sistema para el crecimiento de películas delgadas por el método de recubrimiento por inmersión o dip coating(Universidad EAFIT, 2012) Morales Taborda, Jeyver André; Velásquez Torres, Álvaro Andrés; Urquijo Morales, Jeaneth PatriciaÍtem HexFlex Mechanism Modeling by Design of Computer Experiments(Springer London, 2010-04) Acosta, Diego; Restrepo, David; Ruíz, Oscar; Durango, Sebastián; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAECompliant mechanisms are an instance of mechanical devices designed to transfer or transmit motion, force, or energy from specified input ports to output ports by elastic deformation of at least one of its members -- The main advantage of compliant mechanisms with respect to traditional rigid-link mechanism is that fewer parts, fewer assembly process and no lubrication are required -- The HexFlex is a parallel compliant mechanism for nano-manipulating that allows six degrees of freedom of its moving stage -- This mechanism was designed for high precisión an repeatability -- This article presents a methodology to model compliant mechanisms behavior under quasi-static conditions using computer experiments, reducing costs of experimentation of product development -- The methodology is used to establish a mathematical model that relates the actuator forces at the input ports with the position and orientation the end-effector stage of the Hexflex -- This mathematical model has direct application in model-based control as an advantage with respect to other models, e.g. Finite Element Method -- The mathematical model of the HexFlex is achieved using metamodels -- The term methamodel is used to represent a simplified and efficient mathematical model of unknown phenomenon or computer codes – The metamodel of the HexFlex is performed from virtual analyses made using the Finite Element Method (FEM) -- Simulations of the metamodel were made founding good accuracy with respect to the virtual experimentsÍtem Modelización y simulación numérica de efectos de confinamiento en el grafeno(Universidad EAFIT, 2011) Villegas Pulgarín, Edward Yesid; Vélez Ruíz, Mario ElkinÍtem Propuesta de plan de mercadeo para la spin off Bottom de la Universidad EAFIT(Universidad EAFIT, 2022) Guevara Zapata, Ariadna; López Moreno, Martha CeciliaThis work takes place in Colombia, in the department of Antioquia, in the city of Medellín. It has a marketing focus on companies in the filter sector. The general objective is to design a marketing plan for a Spin-Off of the Nanofilters sector of the Aburrá Valley metropolitan area, specifically the Bottom company (EAFIT University Spin Off) that allows it to identify its external and internal environment, weaknesses and strengths. With the aim of entering the filter market in a successful way, with growth and lasting over time. To start, the company is presented, its situation and its market are analyzed. In this way we can identify how the Spin-Off is currently. The objectives of this market plan are proposed, according to the weaknesses and opportunities. The pertinent research to be carried out and its respective tool are suggested. Then, the marketing mix strategies that are recommended to execute at the Spin-Off are described. Finally, topics such as budget, schedule, indicators and lessons learned are addressed. As a final objective, a document is presented with all the information collected and the results obtained.Ítem Thermodynamics Theory for Damage Evolution in Solids(Springer New York, 2015-01-01) Basaran, Cemal; Nie, Shihua; Gomez, J.; Gunel, Eray; Shidong Li; Minghui Lin; Hong Tang; Chengyong Yan; Wei Yao; Hua Ye; Basaran, Cemal; Nie, Shihua; Gomez, J.; Gunel, Eray; Shidong Li; Minghui Lin; Hong Tang; Chengyong Yan; Wei Yao; Hua Ye; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica AplicadaIn this chapter the thermodynamic theory behind damage mechanics is presented. The presented damage evolution model is purely physical, rather than empirical. Entropy production rate is used as a damage metric.Ítem Validation d’une approche numérique permettant la simulation du comportement des tôles d’épaisseur submillimétrique(Universidad EAFIT, 2008) Echeverri Restrepo, Sebastián; Bonnet, Nicolás; Lipinski, Pawel; Tidu, AlbertLes micropièces sont des pièces ou des structures qui ont des dimensions dans le domaine submillimétrique et sont très utilisées dans les dispositifs électroniques et micromécaniques -- Lors de leur fabrication il faut tenir compte d’un certain nombre de particularités dans leur comportement liés au changement d’échelle, appelés effets de taille -- Le premier objectif de ce travail de master est de valider une approche numérique proposée dans le cadre de la thèse de doctorat de BONNET [1] en faisant des mesures expérimentales pour comparer les résultats -- Le deuxième objectif consiste en avancer l’implémentation d’une autre approche numérique dans le code d’éléments finis ABAQUS® pour simuler un comportement plastique -- Dans un premier temps, une campagne d’essais expérimentaux a été menée pour obtenir des éprouvettes avec une épaisseur submillimétrique et une taille de grains moyenne de quelques millimètres -- Ceci, pour être sûr que les effets de taille seraient présentés -- Dans un deuxième temps, des essais expérimentaux en traction sont réalisés sur les éprouvettes préparées -- Sur ces éprouvettes sollicitées, des mesures de l’évolution des orientations cristallographiques et de la topographie sont faites -- Parallèlement, une modélisation numérique d’un essai de traction est mise en œuvre en utilisant la routine implémentée par BONNET [1] -- Finalement, les résultats obtenus avec les méthodes expérimentales et numériques sont comparés et analysés pour parvenir à un premier ensemble de conclusions