Simulation of shear plugging through thin plates using the GRIM Eulerian hydrocode

Ballistic experiments have been performed using aluminum spheres against 10 -mm rolled homogenous armour (RHA), MARS270, MARS300, and titanium alloy pl ates to investigate the influence of the plugging mechanism on material pro perties. The experiments have measured the threshold for plug mass and velo city as well as the recovered aluminum sphere mass over a range of velociti es. Some of the experiments have been simulated using the in-house second g eneration Eulerian hydrocode GRIM. The calculations feature advanced materi al algorithms derived from interrupted tensile testing techniques and a tri axial failure model derived from notched tensile tests over a range of stra in rates and temperatures. The effect of mesh resolution on the results has been investigated and understood. The simulation results illustrate the im portance of the constitutive model in the shear localization process and th e subsequent plugging phenomena. The stress triaxiality is seen as the domi nant feature in controlling the onset and subsequent propagation of the cra ck leading to the shear plug. The simulations have demonstrated that accura te numerics coupled with accurate constitutive and fracture algorithms can successfully reproduce the observed experimental features. However, extrapo lation of the fracture data leads to the simulations overpredicting the plu g damage. The reasons for this are discussed.