Implosion and Blast Response of Metallic and Composite Structures in Underwater Environments
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.^
Helio David Sega Matos,
"Implosion and Blast Response of Metallic and Composite Structures in Underwater Environments"
Dissertations and Master's Theses (Campus Access).