An investigation into the deformation and tearing of thin circular plates subjected to impulsive loads
Includes bibliographical references. === This investigation, primarily experimental, examines the failure of circular plates subjected to impulsive velocities. The experiments are conducted on fully clamped circular steel plates subjected to a uniformly distributed impulse. The strain-rate-sensitive...
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| Format: | Dissertation |
| Language: | English |
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University of Cape Town
2015
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| Online Access: | http://hdl.handle.net/11427/14564 |
| Summary: | Includes bibliographical references. === This investigation, primarily experimental, examines the failure of circular plates subjected to impulsive velocities. The experiments are conducted on fully clamped circular steel plates subjected to a uniformly distributed impulse. The strain-rate-sensitive mild steel plates fail with mode I (large ductile deformation), mode II (tensile-tearing and deformation) and mode III (transverse-shear) failure modes. The impulse is measured by means of a ballistic pendulum upon which the test plates are attached. During mode II and mode III failure the complete circumferential tearing of the test plate produces a circular disc. The velocity of this disc is recorded. An energy analysis is performed on the test results and an energy balance equation is formulated. Einput = Edeformation + Etearing + Edisc. The input and disc energies are obtained from the experimental measurements and the deformation energy is predicted by using the final deformed height and a shape function together with a rigid-plastic energy analysis adopted by Duffey. Etearing refers to the energy for tensile-tearing in mode II failure or the energy for transverse-shear in mode III failure. Good correlation is found and the experiments show good repeatability. The threshold velocities for the onset of failure modes II and III are given. |
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