Thesis (M.App.Sc.) - Carleton University, / Includes bibliographical references (p. 97-99). Also available in electronic format on the Internet.

Thesis (M.App.Sc.) - Carleton University, 2005. / Includes bibliographical references (p. 168-175). Also available in electronic format on the Internet.

Thesis (Ph.D.) - Carleton University, 2006. / Includes bibliographical references (p. 144-152). Also available in electronic format on the Internet.

Thesis (Ph. D.)--Lehigh University, 2004. / Includes vita. In two parts. Includes bibliographical references (leaves 323-327).

Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Ume, Charles; Committee Member: Chen, Ye-Hwa; Committee Member: Michaels, Jennifer; Committee Member: Sadegh, Nader; Committee Member: Vachtsevanos, George. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (November 13, 2006) Vita. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:27:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-23Bitstream added on 2014-06-13T19:34:57Z : No. of bitstreams: 1 siqueira_rhm_me_guara.pdf: 2998846 bytes, checksum: 93d53da99dcf0c77fbfd2d8211be16f7 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / A soldagem a laser (laser beam wealding – LBW) é uma tecnologia promissora entre os novos processos utilizados na fabricação de estruturas aeronáuticas. A tecnologia LBW pode ser aplicada na soldagem dos reforçadores ao revestimento em substituição ao processo tradicional de rebitagem. Este trabalho pretende realizar a caracterização química, microestrutural e mecânica de juntas, tipo “T”, de alumínio aeronáutico AA 6013 soldadas a laser, sem a introdução de metal de adição, e submetidas a dois diferentes tratamentos térmicos pós-soldagem. As analises químicas e microestruturais foram realizadas para avaliar as alterações geradas pela soldagem nas regiões próximas ao cordão de solda e a influência do tratamento térmico pós-soldagem, em relação à composição química e a microestrutural. E os ensaios mecânicos foram realizados para avaliar as propriedades mecânicas da junta e o ganho em resistência mecânica nas amostras submetidas a tratamento térmico pós-soldagem. A análise química revelou que há uma variação nas concentrações dos principiais elementos de liga e a análise microestrutural mostrou que no cordão de solda existe a presença de microtrincas e na interface entre o material de base e o cordão de solda há a formação de zonas de liquação. Já o ensaio de dureza mostrou que os tratamentos térmicos pós-soldagem não promovem alterações nos valores de dureza no cordão de solda, apenas no material de base, o ensaio de tração revelou que os tratamentos térmicos aumentam o limite de resistência, mas diminui a deformação para as amostras tratadas pós-soldagem e o ensaio de fadiga mostrou que os defeitos observados na análise microestrutural são determinantes na vida em fadiga. Portanto... / Laser Beam Welding (LBW) is a promising technology among the new processes used in aeronautical structures fabrication. The LBW technology may be applied in the welding of stringer of the skin and is able to replace the traditional method of reveting. This work intends to make a chemical, microstructural and mechanical characterization of “T” joints, using a laser welded AA 6013 aeronautical aluminum, without filler addition and after two different post welding heat treatments. The chemical and microstructural analyses were made in order to evaluate welding effects near to the weld and the influence of the post welding heat treatment. Mechanical tests were realized in order to evaluate the welding joint properties and the effects of post welding thermal treatments. The chemical analysis showed that there is a changing in concentration of main alloy elements. The microstructural analysis revealed that there exist some microcracks and there is a liquidation zone between the weld and the base material. The hardness tests showed no changes on hardness of the weld after post weld heat treatment, but there is a difference in the base material. The tensile tests showed an increase in the ultimate strength after post weld heat treatments but with a decrease in elongation. The fatigue tests showed that the defects observed in the microstructural analyses are important to the fatigue life. Hence, after these tests and analysis, we can state that LBW technology is promising to the replacement of riveting processes, but the defects observed must be controlled in order to increase the fatigue life

No description available.

Seismic design criteria have been heavily improved by the Federal Emergency Management Agency (FEMA) after the Northridge CA earthquake in 1994. Most of the damage observed was caused by brittle failure of moment frame connections. This failure was induced by the formation of the plastic hinge at undesirable locations in the beam and the column near the connection. Using welded flange plate (WFP) connections will force the formation of the plastic hinge away from the face of the column while preventing the brittle failure of the moment connection. FEMA-350 design criteria recommendations for WFP connections suggest that the plastic hinge will form away from the face of the column directly under the cover plate. The purpose of this research is to prove that the plastic hinge will form away from the face of the column, at a distance of approximately half the depth of the beam away from the cover plate. The further away the plastic hinge is from the face of the column the higher the connection demands. Therefore, underestimating the location of the plastic hinge could lead to under designed connections. The modeling and analysis of WFP connections was performed using finite element analysis software. A total of eight models with half beam half column configuration were considered in this study. Each selected section of beam and column was first designed, modeled and analyzed using WFP connections design recommendations from FEMA-350, with calculations modifications to account for the proposed plastic hinge location. Results were computed and comparisons were made in terms of plastic hinge location from the cover plates. Strength obtained for each model using finite element analysis software was also compared with hand calculations. This research also proves that increasing the thickness of the cover plates will generate an increase in the connection capacity and strength.

M.Ing. (Mechanical Engineering) / The use of longitudinally welded tube are limited in certain sectors of industry due to the belief that seamless tubes are superior. The main objective of this study was to try and prove that sufficient resistance to internal pressure could be achieved by longitudinally welded type 304L stainless steel tubes, while subjected to various external forces. A knowledge of plasticity theory and failure criteria provides the basis of the different mechanisms of tube failure. Four different tests were performed using different external forces, while internal pressure was increased until failure occurred. It was found that test specimens failed after reaching acceptable pressures, irrespective of the external loading conditions.