Converging shocks in water and material effects

2013-10-14During events of underwater explosions, the resulting shock waves poses extreme mechanical loadings to the nearby naval structures. Therefore this dissertation studies the shock wave dynamics of water inside a solid structure and the dynamical response of such a structure. The goal is to understand the effect of underwater shock wave focusing on materials possessing various mechanical properties with an emphasis on lightweight materials. This research has a direct impact on the material selection and hydrodynamic considerations in naval architecture. ❧ Two steps are taken towards the research goal. First, a special geometry of the confinement structure called logarithmic spiral is chosen. This type of shape will help to focus the shock wave, which will yield the maximum energy at the focal region. Numerical simulations are conducted to confirm the derived characteristics of the geometry. When including weak material coupling with the liquid, both experiments and simulations demonstrate that the shock dynamics in water is sensitive to the coupling. ❧ Secondly, significant coupling effect is introduced by reducing the thickness of the solid structure. Experimental and numerical investigations are both carried out to shed light onto the details of the fluid-structure coupling. The results revealed that the thickness of the material has the most significant impact on both the fluid dynamics and the deformation mechanisms of the structure. Lightweight carbon fiber composite structures are also studied under the same framework. ❧ Along the way, this dissertation also proposes and designs experimental methodologies to enable the study of highly dynamic underwater events