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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

Troca rápida de ferramenta com auxilio de simulação computacional aplicada em processo de extrusão de compostos

Janamilton Medeiros Oliveira 29 January 2013 (has links)
The competitively has transformed manufacturing environments, where the companys processes with increasingly complex seeking to reduce waste generated in manufacturing environment that not add value to the product and thus the setup machine downtime includes wasting time. The methodology for rapid exchange tool is used to reduce the time setup increasing productivity line where is implanted. This work must a main goal is implement as a technique for quick change tool in a line of extrusion of polymeric compounds with aid of computer simulation. Company producing polymeric compounds have as goal to be world in reference time setup with respect to other plants and accordingly justified the implementation of rapid exchange tool in your production line. This work have a approach quantitative diagnosis with the current situation, by means of documents and methods used, and trial with intervention of variables with computer simulation of the current situation and changes suggested by simulation. The results obtained after the implementation of expressive and improvements have been following the steps for proposal literature, got to get up, in certain cases of setup, the `one touch exchange of die and thus using the rapid exchange tool methodology as a tool for continuous improvement, attained the goal in reducing setup. / A competitividade vem transformando os ambientes de manufatura, onde as empresas com processos cada vez mais complexos procuram reduzir os desperdícios gerados no ambiente fabril que não agregam valor ao produto e desse modo o setup de máquina engloba tempo ocioso. A metodologia de troca rápida de ferramenta é utilizada para reduzir os tempos de setup aumentando a produtividade da linha onde é implantado. Esta dissertação tem como objetivo principal implantar a técnica de troca rápida de ferramenta em uma linha de extrusão de compostos poliméricos com auxilio de simulação computacional. A empresa produtora de compostos poliméricos tem como meta ser referência mundial em tempo de setup com relação a outras plantas e dessa forma justifica-se a implantação da troca rápida de ferramenta em sua linha de produção. Esta dissertação utiliza uma abordagem quantitativa com diagnóstico da situação atual, por meio de documentos e métodos utilizados, e experimentação com intervenção das variáveis com simulação computacional e modificação da situação atual sugerida pela simulação. Os resultados obtidos após a implantação das melhorias foram expressivos e, seguindo as etapas proposta pela literatura, conseguiu-se chegar, em determinados casos de setup, à troca de ferramenta em um toque e dessa forma, utilizando a metodologia de troca rápida de ferramenta como ferramenta de melhoria contínua, foi possível atingir a meta na redução do tempo de setup.
2

Experimentell-numerische Analyse mechanischer Eigenschaften von Aluminium/Magnesium-Werkstoffverbunden

Lehmann, Thomas 29 June 2012 (has links)
Es werden hydrostatisch stranggepresste Aluminium/Magnesium-Verbunde untersucht. Mittels verschiedener Rissdetektionsmethoden wird die Beschaffenheit des Interface analysiert. Es erfolgt die Bestimmung von Fließkurven der verpressten Einzelwerkstoffe bei Raumtemperatur. Des Weiteren erfolgen Eigenspannungsanalysen mit dem Bohrlochverfahren und einer speziellen numerischen Auswertungsmethode, welche den Entstehungsprozess der Eigenspannungen berücksichtigt. Zur Analyse der Festigkeitseigenschaften und des Deformationsverhaltens des Interface werden Biegeversuche in einem erweiterten Temperaturbereich durchgeführt. Die Deformationsanalyse erfolgt mittels Digital Image Correlation. Des Weiteren finden in den Festigkeitsuntersuchungen Push-Out-Versuche Anwendung. In bruchmechanischen Analysen wird die Interfacerissspitze von speziell entwickelten Proben unter Mode I-Bedingungen, bezogen auf den homogenen Fall, beansprucht. Die bruchmechanischen Größen – kritischer betragsmäßiger Spannungsintensitätsfaktor und kritische Energiefreisetzungsrate – werden auf Basis der Experimente, der numerischen Simulation der Rissspitzenbeanspruchung sowie der für die linear-elastische Bruchmechanik des Interfacerisses geltenden Nahfeldgleichungen berechnet. / Hydrostatic coextruded aluminum/magnesium compounds are analyzed. By means of different methods of crack detection, the quality of the interface is investigated. Plastic behavior of the basic materials at room temperature is determined. Furthermore, residual stress analyses are performed using the hole drilling method and a special numerical evaluation procedure, which considers the formation process of the residual stresses. The strength and deformation behavior of the interface are determined by means of bending tests in an extended temperature range. Digital Image Correlation is used to analyze the deformation. Furthermore, push out tests are performed to determine the interface strength. In the course of fracture mechanical analyses, the crack tip of specially developed specimens is stressed under Mode I conditions (relating to homogeneous material). The fracture mechanical values – critical absolute value of the stress intensity factor and critical energy release rate – are determined by the use of experiments, numerical analyses of the crack tip fields as well as the equations of the linear elastic near field equations of interface fracture mechanics.

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