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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Comportement à l'indentation et à la rayure de verres métalliques et silicatés / Mechanical behaviors of metallic and silicate glasses from indentation to scratch

Hin, Raveth 21 November 2017 (has links)
Le comportement mécanique du verre silico-sodo-calcique soumis à un contact ponctuel peut être amélioré par trempe. Les effets de trempe se manifestent par des gradients de propriétés sur le comportement du verre rendant la modélisation plus complexe. Ce travail a porté sur la modélisation et la simulation des verres non trempés et trempés soumis aux essais de nano-indentation et de nano-rayage. Les outils de simulation par éléments finis ont été développé et validés sur le verre métallique, choisi en raison de son comportement plastique connu. En comparant avec les données expérimentales, nous avons observé que les paramètres du matériau et les conditions expérimentales pouvaient donner la même réponse sur la courbe force-déplacement et l'empreinte. L’identification des propriétés du matériau doit être basée sur des comparaisons avec des simulations considérant la géométrie réelle de l'indenteur, la souplesse de la machine et le tilt de surface de l'échantillon. Les stratégies développées permettent de faire des identifications sur le comportement du verre silico-sodo-calcique. Dans la famille du verre silicaté, le verre silico-sodo-calcique a un comportement plastique semblable au verre de silice qui est affecté non seulement par le mécanisme de cisaillement mais aussi par la densification. Il est essentiel donc d'étudier le comportement densification/cisaillement du verre de silice car il est largement discuté dans la littérature. La comparaison des résultats de simulation par plusieurs modèles avec les courbes force-déplacement et les images d'empreinte a montré que la modélisation de la densification, en prenant en compte l'écrouissage et la modification des modules élastiques, est suffisante pour décrire le comportement des verres silicatés. Enfin, les connaissances sur les simulations des essais à chargement ponctuel et la modélisation du comportement du verre ont guidé une étude sur les effets du gradient de propriétés dans les verres trempées thermiquement et chimiquement. / The mechanical behavior of soda-lime-silica glass subjected to contact damage can be improved by tempering. The effects of tempering created tailor properties and the glass behavior more complicated. Therefore, this work studied the modeling and simulation of non-tempered and tempered glasses subjected to the nano-indentation and nano-scratch tests. The finite element simulation tools have been primarily validated and the metallic glass was chosen for the studies because of its known plastic behavior. By comparing with the experimental data, we have observed that the parameters of material model and the experimental conditions could give the same response on load displacement curve and imprint. The evaluation of material properties must be based on the comparisons with fully modeled simulation considering the real geometry of the indenter, the compliance of the instrument and the tilting of the sample surface. The developed strategies allow identification of soda-lime-silica glass behavior. Similar to that of silica glass, the plastic behavior of soda-lime-silica glass is not only affected by the shear mechanism but also the densification. Hence, it is essential to study the shear/densification behavior of silica glass as it is widely discussed in the literature. The comparison of simulation results by several models with the load displacement data and the images of imprint showed that the modeling of densification by taking into account the hardening and the change in elastic moduli is sufficient for describing the behavior of silicate glasses. Finally, the knowledge about the simulation of the contact loading tests and the modeling of glass behavior guided a study on the coupling of tailored properties effects in the thermally and chemically tempered glasses.
2

Propuesta de mejora para la reducción de productos defectuosos de una empresa de fabricación de vidrios de seguridad, aplicando herramientas Lean Manufacturing / Improvement proposal for the reductin of defective products of a safety glass manufacturing company, applying Lean Manufacturing tools

Herrera Yénkenes, Miguel Ernesto, Montes Caja, Gabriel 24 July 2021 (has links)
La presente tesis de investigación está orientada en la aplicación de herramientas Lean manufacturing para mejorar los procesos productivos de una empresa que fabrica y comercializa vidrios de seguridad para el rubro de la construcción. Actualmente, la empresa Cánovas S.A.C, require reducir el porcentaje mensual de productos defectuosos que se obtienen del procesamiento en la linea de producción de vidrio templado. El objetivo de la empresa, es disminuir el porcentaje mensual de productos defectuosos a un nivel igual ó menor al 4%, el cual se ha determinado a traves de un desarrollo estadístico, acompañado de artículos de investigación que respaldan dicho nivel porcentual. En el primer capítulo se describió el analisis del sector donde se desarrolla la empresa, es decir, la industria del vidrio, algunos conceptos generales, metodologías, casos de exito aplicando las herramientas de ingenieria, asi como tambien el marco normativo que involucra las operaciones de la empresa. Para el desarrollo del segundo capitulo, se destacan las principales caracteristicas de la organización, la identificación del problema y sus evidencias, analisis de los motivos y las causas que generaron la mayor cantidad de productos defectuosos en la linea de producción de vidrio templado, En el tercer capitulo se procede a evaluar y desarrollar el diseño integral propuesto para la solución. En el cuarto capitulo, este diseño propuesto, se validó en un modelo de simulación mediante el software Arena, el cual nos mostró los analisis de los resultados obtenidos en cada etapa del proceso productivo, del mismo modo, se presento el analisis financiero con los resultados económicos obtenidos para la implementación. Finalmente se muestran las recomendaciones y conclusiones obtenidas del analisis del proyecto de investigación. / This research thesis is focused on the application of Lean manufacturing tools to improve the production processes of a company that manufactures and markets safety glass for the construction industry. Currently, the company Cánovas SAC, requires to reduce the monthly percentage of defective products that are obtained from the processing in the tempered glass production line. The objective of the company is to reduce the monthly percentage of defective products to a level equal to or less than 4%, which has been determined through statistical development, accompanied by research articles that support said percentage level. In the first chapter, the analysis of the sector where the company is developed was described, that is, the glass industry, some general concepts, methodologies, success stories applying engineering tools, as well as the regulatory framework that involves the operations of the company. For the development of the second chapter, the main characteristics of the organization are highlighted, the identification of the problem and its evidences, analysis of the reasons and causes that generated the largest number of defective products in the tempered glass production line. third chapter proceeds to evaluate and develop the integral design proposed for the solution. In the fourth chapter, this proposed design was validated in a simulation model using the Arena software, which showed us the analysis of the results obtained in each stage of the production process, in the same way, the financial analysis was presented with the economic results obtained for the implementation. Finally, the recommendations and conclusions obtained from the analysis of the research project are shown. / Trabajo de Suficiencia Profesional
3

Statická analýza stavebních prvků ze skla / Static Analysis of Structural Elements of Glass

Hořký, Radek January 2013 (has links)
They analyzed the various factors affecting the design or evaluation of structural glass. Within evaluation of structural glass element is checked selected concepts of linear elastic fracture mechanics. For modeling is used programme system ANSYS based finite element method. The results are compared with the analytical solution.

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