Ph.D. - Mechanical Engineering
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ItemConstant-Volume Carbonization of Biomass.( 2018-08)
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ItemFinite Element Modeling of the Friction Stir Forming Process([Honolulu] : [University of Hawaii at Manoa], [August 2016], 2016-08)This research is focused on developing the process that joins lightweight dissimilar materials with the maximum strength conceivable and with a minimum brittle intermetallic-formed region. It is difficult to weld these materials together because the properties of the dissimilar materials are usually prominently different. Friction Stir Forming process can achieve this objective, and it can overcome the current challenges that other processes are facing in a cheaper way without using rivets, bolts, fluids, substantial energy for heating, or additional mass additions. This process can achieve the objective by stir heating one sheet and forming it into a pre-punched or pre-drilled hole in the second sheet. The result is forming a mechanical interlocking joint with minimal mechanical force by using relatively simple machinery and simple techniques. The first part of this research was focused on exploring the feasibility of concept and finding the optimal values of the important parameters such as spindle and plunge speed, torque, geometrical dimensions of the tools, etc. This experimental step gathered necessary data in order to set up a foundation for the following finite element analysis (FEA) work. For the rest of the research, Abaqus software was used to accomplish the FEA task together with a validation experiment. As a product of the modeling segment, predictions can be accurately and easily determined for different conditions, shapes, and materials. This will allow further understanding of the potentials of the technology, and it will facilitate an expansion of this new valuable technology. The research outcomes highlighted materials behavior during the FSF process, the major challenges for an accurate FEA model, and temperature distribution of the work materials. The research also identified opportunities for further research.