Influence of extreme velocities on dynamic cavity expansion

Abstract

Cavitation can broadly be described as the unstable expansion of an empty void in a body, usually occurring when loads on the body reach a critical level. In this thesis, dynamic cavity expansion (DCE) in solids is of particular interest. Cavity expansion has been studied extensively under quasi-static and dynamic loading conditions. However, the behavior of cavitation fields with extreme dynamic expansion velocities have little been studied, especially in materials without a definite yield point. In this thesis, DCE in a hardening elastoplastic medium is considered under extreme velocities. Two nonlinear differential equations are used to describe the steady-state expansion. Using numerical integration, this system is solved to explore the behavior under extreme expansion velocities. By gradually increasing the expansion velocities, we find that a singularity occurs in the governing system, indicating a shock wave emerging and propagating through the material. With this limit velocity of the material known, further characteristics of the material can be described and investigated.