Date of Award
Doctor of Philosophy in Mechanical Engineering and Applied Mechanics
Mechanical, Industrial and Systems Engineering
Six different experimental studies were conducted to evaluate the dynamic response of marine structures. These studies examine the: implosion performance of polyurea coated aluminum shells; implosion process of marine grade metallic structures; implosion mechanics within a confining environment; the response of confined blast-initiated implosions; generation and mitigation of implosion induced hammer waves; and behavior of artificially aged composite structures subjected to blast loads. During the experiments, two high-speed cameras are used to record the event, and underwater pressure transducers are used to measure the pressure signatures. A high contrast speckle pattern is placed on the specimen so three-dimensional Digital Image Correlation can measure full field surface displacement, velocities, and strains. When explosives are in use, a third high-speed camera records the explosive’s behavior and bubble mechanics. For the artificially aged composite study, a Coupled Eulerian-Lagrange finite element model was created to supplement the experimental results. The findings of these studies show that: polyurea coatings can drastically reduce the emitted energy of an implosion event; marine grade metals can release less energy during an implosion event if fracture is present; confined implosions have different collapse mechanics than free-field implosions; confined blast-initiated implosions can have devastating pressure signatures if the hammer pressure is in phase with the bubble pulse; high pressures from water hammer waves are mitigated if a sacrificial foam material is used at the hammer location; and weathered composites have a lower blast performance due to degraded material properties.
Sega Matos, Helio David, "Implosion and Blast Response of Metallic and Composite Structures in Underwater Environments" (2017). Open Access Dissertations. Paper 538.