Numerical prediction of cavitation damage based on shock-induced single bubble collapse near solid surfaces

Abstract

The prediction of cavitation damage through bubble collapse impact loads (BCIL) is essential, because it opens the opportunity to develop a phenomenological model that can be useful to improve the design process of hydraulic machinery components. Owing to the fast process and small-scale phenomena, direct measurement of the BCIL is greatly challenging if conducted through experimental methods. This study aims to reveal the underlying deformation process of solid materials under a single BCIL using a coupled multi-material hydrocode solver. Three different material constitutive models – purely elastic, elasto-plastic, and strain-hardening – were investigated through various types of metals and polymers. A detached single air bubble was placed near the solid surface inside a long and narrow tube. A planar shockwave was introduced to induce the bubble to collapse, resulting in BCIL that is high enough to cause plastic deformation on the solid surfaces. Measured BCILs from solid material cases show good agreement with the cavitation erosion test result of A1050, SS400, Epoxy resin, PP, and HDPE. These findings indicate that, in the case of metals, the deformation process can be inferred to acoustic impedance since impact energy evaluation shows no significant change when material plasticity is introduced. However, in the case of polymers, the deformation process is greatly influenced by yielding.