Modeling and simulations of high and hypervelocity impact of small ice particles

We present a computational model based on the Hot Optimal Transportation Meshfree (HOTM) method and a thermo-visco-elasto-plastic constitutive model for the high-fidelity simulation of high and hypervelocity impact of small ice particles. The competition and combination among various energy dissipation mechanisms in the high energy density event, including plasticity, fracture/fragmentation, and phase change, are predicted by minimizing the thermomechanical system's potential energy within a variational structure. The variational Eigenerosion algorithm is incorporated in the HOTM method to simulate crack nucleation, propagation, and fragmentation. A multiphase thermo-visco-elasto-plastic model is developed to describe the dynamic response of ice under extreme loading conditions, such as strain and strain-rate hardening, temperature-dependent strength, pressure-dependent viscosity, and phase diagram. The proposed computational framework is validated by comparing to experimental observations and measurements from two ballistic tests at different strain rates. Numerical studies are performed for the impact tests of a microscopic spherical ice particle(⌀800nm) against a Ti-6Al-4V plate at velocities ranging from 250m/s to 5000m/s at an initial temperature of 200K. The evolution of failure modes in the ice projectile is well captured as a result of the energy partitioning explicitly into plasticity, fracture and phase change at different moments. The analysis demonstrates the transition of the dominant failure mechanism due to the increasing input energy density and the nature of stress wave propagation. The competition between fracture and phase change, in the presented configuration of numerical studies, starts when the impact velocity approaching 800m/s and thermal effects play a critical role in determining the local deformation and failure.