Ballistic impact behaviour of newly developed armour grade steel: An experimental and numerical study

High strength steel plates are majorly utilized for civil and military vehicles for ballistic protection against various threat levels. In this work, an experimental and numerical study has been conducted on a newly developed armour steel grade. Four different ductile fracture criteria have been used in the numerical simulations, namely Modified Johnson-Cook (MJC), Cockcroft-Latham (CL), Constant failure strain (CFS) and Maximum Shear (MS) stress failure criteria. Suitable experiments were conducted for material model parameter estimation and a simulation study was conducted in LS-DYNA to evaluate its performance in a plate impact simulation. The results were correlated with an actual Impact test done with a plate of dimension 1000 x 1000 x 6 mm with 7.62 x 51 mm NATO ball ammunition for NIJ (National Institute of Justice) Level 3 protection. Modified Johnson-Cook, Cockcroft-Latham and Constant strain failure criteria are in good agreement with experimental results. Maximum Shear stress failure criteria failed to predict the experimental results.