Matching Items (3)
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- All Subjects: Mechanical Engineering
- All Subjects: Mechanics
- All Subjects: Triangles
- Member of: Theses and Dissertations
- Status: Published
Description
Abstract A study was conducted on three models of the medieval siege engine, the trebuchet. The three models analyzed were the "see-saw", the hinged, and the floating arm trebuchet. Of these models, the mathematical model of each was determined. With his model, the most efficient model was determined to be the floating arm trebuchet, with a range efficiency of 0.8275 and an energy efficiency of 0.8526. The hinged trebuchet achieved efficiencies of 0.8065 for both range and energy efficiency and the "see-saw" with efficiencies of only 0.567 and 0.570, respectively. Then, the floating arm trebuchet's arm length ratio and sling length were then optimized. It was determined that the optimal arm length ratio was approximately 1:2, where the short arm is 1.7 feet and the long arm is 3.3 feet. The optimized sling length was 4.45 feet. Finally, the mathematical models were compared to full scale models. These ranges of the full scale models were surprisingly accurate with what was predicted. The hinged trebuchet model had the largest percentage error at 8.4%.
ContributorsEstes, Stephen Louis (Co-author) / Estes, Nathan (Co-author) / Liao, Yabin (Thesis director) / Trimble, Steven (Committee member) / Bucholz, Leonard (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2013-05
Description
The study of the mechanical behavior of nanocrystalline metals using microelectromechanical systems (MEMS) devices lies at the intersection of nanotechnology, mechanical engineering and material science. The extremely small grains that make up nanocrystalline metals lead to higher strength but lower ductility as compared to bulk metals. Effects of strain-rate dependence on the mechanical behavior of nanocrystalline metals are explored. Knowing the strain rate dependence of mechanical properties would enable optimization of material selection for different applications and lead to lighter structural components and enhanced sustainability.
ContributorsHall, Andrea Paulette (Author) / Rajagopalan, Jagannathan (Thesis director) / Liao, Yabin (Committee member) / Barrett, The Honors College (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2014-05
Description
Pseudo-steady state (PSS) flow is a dominant time-dependent flow regime during constant rate production from a closed reservoir. Using Chen's (2016) exact analytical solution for the PSS flow of a fully-penetrated fractured vertical well with finite conductivity in an elliptical drainage area, the computational time required to solve for the PSS constant b_D,PSS is greatly reduced. This constant is the inverse of the productivity index, J_D,PSS, which is often used in modern fracture design optimization. This paper correlates the PSS flow of a fully-penetrated fractured vertical well in triangular drainage areas to Chen's solution for an elliptical drainage area using shape factors. Numerical solutions for the PSS constant are created using COMSOL, which uses a 2D model of the fractured reservoir to output time and pressure data. For equivalent reservoir properties, the numerical data for the triangular reservoir yields a PSS constant that can be directly compared to the PSS constant obtained using Chen's solution. Lack of access to the Subsurface Flow Module of COMSOL greatly limited the number of simulations that could be run, thus more simulations would significantly improve the accuracy and applicability of the triangular shape factor by making it a function of the penetration ratio through nonlinear regression methods.
ContributorsLight, Christopher Ting-Yu (Author) / Chen, Kangping (Thesis director) / Liao, Yabin (Committee member) / Mechanical and Aerospace Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2017-05