Comparative analysis of material models on the fracture behavior of Weldox 700E steel plate under high velocity impact

The mathematical modeling of material behavior plays a crucial role in the finite element analysis of impact problems, particularly within the framework of nonlinear dynamics. This study investigates the influence of various material models on the fracture behavior of a 4 mm thick Weldox 700E steel plate subjected to high-velocity impact by a blunt-nosed cylindrical projectile. To capture the nonlinear deformation and failure mechanisms, five material models are employed: Johnson-Cook (JC), Wang Modified Johnson-Cook (WMJC), Dey Modified Johnson-Cook (DMJC), Holmen Modified Johnson-Cook (HMJC), and Xiao Modified Johnson-Cook (XMJC). Continuum damage mechanics is utilized to model material degradation, while Johnson-Cook damage fracture strain is implemented for failure prediction. The constitutive models are integrated into the nonlinear finite element solver LS-DYNA using an external FORTRAN subroutine, enabling a detailed analysis of the dynamic fracture response of the flat target plate. Model parameters, including material and damage constants, are calibrated using experimental data. The study aims to assess the influence of these models on residual velocity, fracture patterns, material degradation, and damage evolution, providing insights into the nonlinear dynamic behavior of high-strength steel under extreme loading conditions.