Modelling plasticity in shock compressed Ta using CPFEM simulations

Modelling plasticity in laser shock experiments presents a major scientific challenge, owing to the high pressures that can be generated and the large strain rates and dislocation densities that can occur. While great progress has been made with both molecular dynamics (MD) and hydrocode simulations, difficulties remain to accurately model dynamic compression at the scales of typical laser experiments, while capturing the physics occurring at the lattice level. We present a dislocation dynamics based crystal plasticity finite element model (CPFEM) to simulate dynamic compression in Ta. Using this approach, we can generate synthetic X-ray diffraction patterns, which can be compared to experimental data. By introducing a homogenous nucleation term, we are able to reproduce the grain rotation behaviour in shock compressed [110] fibre textured Ta found via an in situ femtosecond diffraction experiment performed at LCLS by Wehrenberg et al [1]. UK Ministry of Defence © Crown Owned Copyright 2022/AWE.

[1] Wehrenberg et al, Nature, 550, 496-499 (2017)