A computational and experimental study of the underwater implosion of single and multiple metallic spherical shells

Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (pages 103-104).Analysis of the implosion of pressure vessels in a deep-water environment is an important research area for the ocean engineering community. The majority of previous implosion research focused on the implosion of metallic cylinders, while the implosion behavior of volumes of different geometries and materials is less well researched. The behavior of pressure pulses resulting from the implosion of multiple pressure vessels is also less well researched. This thesis addresses these questions by investigating the implosion behavior of single and multiple spherical shells. Over the course of this research, I designed and predicted the collapse depth of metallic spherical volumes using shell buckling theory, then used a computational tool to model several implosion scenarios of both single and multiple sphere configurations. I then conducted implosion tests of single and multiple spherical shell configurations. The results from the initial computational models were compared with results of experimental tests and used to develop updated computational models that more accurately represented the true geometry of the test articles. Based on the analysis of the results of initial computational models and the experimental results, and the correlation between the updated computational models and experimental results, I identified ways to more accurately model scenarios involving implosions of spherical shells. In addition, I analyzed the behavior of a sympathetic implosion event involving two spherical shells and compared the result of the sympathetic implosion event to that of a single equivalent volume. This thesis concludes with guidance for future modeling and experimental testing efforts.by Emma Grace Ferris.S.M