The motivation behind this study is the lack of specialized analysis regarding internal failure caused by the adiabatic shear hand (ASB) phenomenon in the cold-headed products. Its aim was to present an integrated workability study to improve and assist cold-heading (CH) multistage design procedures to replace the current design rules of thumb, as they are neither effective nor adequate in fulfilling the needs of the new developments in the rapidly expanding CH industry. / To achieve these goals, a comprehensive testing methodology and FE modeling, implemented within ABAQUS/Explicit, were established. This methodology includes an instrumented Drop Weight Compression Test (DWCT) tower equipped with a guided pocket die-set configuration capable of developing internal failure at different stages of ASBs and integrated metallographic inspection techniques. A validated FE model of the DWCT and guided pocket die-set configuration was a valuable tool in establishing the failure criteria and indicating the workability limits. / A detailed experimental and FE study for the ASB stages in the CH process was introduced to uncover the affect of different parameters controlling the failure mechanisms within the ASBs in the CH process. This study investigated the effect of the thermal, geometric and the material flow softening and hardening mechanisms affecting ASB evolution. Moreover, a detailed metallurgical and FE study of the internal ductile and Transformed Adiabatic Shear Band (TASB) failures caused by the ASB phenomenon in DWCT was conducted. / Three ductile failure criteria were introduced to predict the initiation and location of the internal ductile failure in the ASBs. One TASB failure criteria was introduced to predict the phase transformation to undesirable brittle martensite. These failure criteria were employed to establish integrated workability methodologies to indicate the objective workability limits. / Applying these workability methodologies on multistage CH FE models showed that these methodologies are an efficient tool to predict the damage levels and failure initiation locations within the cold-headed bolts. Moreover, these methodologies were successful in optimizing the die designs in order to reduce damage levels.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 265-278).

Thesis (M.Sc. (Hons)) -- University of Western Sydney, Nepean, 2000. / "Thesis submitted for the degree of Master of Engineering (Hons), School of Mechatronic, Computer & Electrical Engineering, University of Western Sydney, Nepean" Bibliography : leaves 129-141.

Thesis (Ph. D.)--Ohio State University, 2008. / Title from first page of PDF file. Includes bibliographical references (p. 172-177).

Mémoire (M.Sc.A.)-- Université du Québec à Chicoutimi, 1992. / Résumé disponible sur Internet. CaQCU Bibliogr.: f. 158-160, 220-221. Document électronique également accessible en format PDF. CaQCU

Thesis (M.S.)--Rochester Institute of Technology, 2009. / Typescript. Includes bibliographical references (leaves 69-72).

Thesis (M.S.)--University of Michigan, 1959.

Made available in DSpace on 2014-06-11T19:28:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-06-15Bitstream added on 2014-06-13T19:57:38Z : No. of bitstreams: 1 silvaneto_jf_me_bauru.pdf: 1785488 bytes, checksum: 20f9f159b1b215b07f4c95af3fa0d932 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / No processo de retificação e utilização de fluidos de corte é uma maneira de implementar a qualidade final ao processo, pois os fluidos têm como finalidade a lubrificação na área de contato entre a peça e ferramenta e a refrigeração das superfícies, assim evitando danificações na superfície da peça. Com isso, a utilização de fluidos de corte tem sido constantemente estudada, visando diminuir a utilização deste, pois a utilização de fluidos de corte tem seus problemas. O custo do produto final aumenta consideravelmente com o uso de fluidos de corte no processo de retificação, além de que os fluidos de corte são substâncias tóxicas e nocivas tanto às pessoas quanto ao meio ambiente. Portanto indústrias, universidades e centro de pesquisas são levados a pesquisar métodos alternativos menos prejudiciais ao meio ambiente. Dentre as alternativas surge e técnica da mínima quantidade de lubrificante (MQL), que também tem suas desvantagens, como por exemplo, a formação de uma borra de óleo na superfície de corte do rebolo, o que gera uma rugosidade maior na peça. Porém, visando minimizar esse problema podem ser usados jatos de ar comprimido incidindo na superfície de corte do rebolo, com o objetivo de limpar a superfície de corte do rebolo, com o objetivo de limpar a superfície do rebolo. Dessa forma, avaliou-se a eficiência desse sistema de ar comprimido para a limpeza e pôde-se verificar que, a utilização da limpeza juntamente com a técnica do MQL, torna-se viável, pois de uma maneira geral a técnica do MQL com limpeza obteve melhores resultados na qualidade da peça e desgaste da ferramenta, em relação ao MQL sem limpeza. A limpeza com um ângulo tangente à superfície do rebolo foi a condição de limpeza que obteve melhores resultados para a limpeza o que comprova que a melhoria na técnica do... / In grinding process the use of cutting fluids is a way to implement the final quality of the process because the fluids are intended for the lubrication in the contact area between the work piece, the tool and the cooling of the surfaces avoiding damages on the work piece surface. However, the use of cutting fluids has been constantly studied in order to reduce its use since this practice brings a lot of problems about. The final product cost increases considerably along with the use of cuting fluids in gringing process, besides those substances are toxic and harmful to people and to the environment as well. Therefore, industries, universities and research center have been taken as sites for investigating less harmfulll alternative methods to the environment. Among such alternatives comes up of minimum quantify of lubricant technique (MQL), which also has some disadvantages, such as the formation of oil sludge on the cut surface of the wheel, which creates a greater surface roughness on the work piece. However, in order to minimize this problem compressed air jets can be used focusing on the cut surface of the wheel, in order to clean it. Thus, we could evaluated the effectiveness of that compressed air system used for cleaning, and it was possible to observe that the use of cleaning with the MQL technique is feasible because from a general view the use of the MQL technique in the cleaning process showed better results in the quality of the work piece and wornout of the tool comparing to the to the MQL with no cleaning. The cleaning with a tangent angle to the surface of the wheel was the condition of cleanliness that showed better results for the cleanliness which proves that the improvements for the MQL techniques does not lead to significant results compared to the conventional technique. However, the MQL technique with cleanliness has its... (Complete abstract click electronic access below)

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Indiana University-Purdue University Indianapolis (IUPUI) / Aluminum extrusion is a metal forming process used for the production of a large variety of solid, semi-solid and complex hollow products. During extrusion, the hot aluminum billet goes under severe plastic deformation as it is forced to flow through a smaller die cavity that defines the final shape of the extruding product. Surface finish and dimensional accuracy are the two most important criteria that specify the productivity and feasibility of the extrusion process which is highly influenced by the flow of aluminum through the deforming die. Therefore, die design is considered as one of the most important characteristics of the extrusion process that influences aluminum flow, quality of the extruding product and its dimensional accuracy. Currently, development of extrusion dies is primarily based upon the empirical knowledge of the die designer gained through trial and error, which inevitability is an expensive, time consuming and ineffective method. However, owing to the technological advancements of this century in the field of finite element modeling, this decade old trial and error method can now be replaced by numerical simulations that not only save time and money but also, can accurately predict the flow of aluminum through a die as well as predict die deformation occurring during the extrusion process The motivation of this research project came from a private extrusion die manufactures need for improving their pioneered modular die based on good analytical and scientific understanding of the dies performance during the extrusion process. In this thesis, a commercial simulation package Deform 3D is used to simulate the thermo-mechanical interactions of aluminum flow through the deforming modular die for the production of Micro Multi-Port (MMP) tubes.