We developed and improved constitutive model, using LS-DYNA second development technology to embed a damaged Johnson-Cook constitutive model of commercial finite element software.Detailed description of structure of iterative algorithm and calculation process are presented. For experiments of perforation of 12 mm thick steel plates by 20 mm diameter projectiles with flat and conical noses, numerical simulations are carried out. Calculation and experiment results are consistent well. It indicates that constitutive algorithm, containing damage constitutive model and damage evolution equation are reasonable and reliable.

We present numerical simulation of Kevlar/Vinyl 3D orthogonal woven composite impacted by a spherical bullet with LS-Dyna software. Orthogonal constitutive equation with damage tensor and Hashin failure criteria are adopted for the Kevlar/Vinyl target. Time history of penetration velocity and loading of bullet show that steady penetration process and residual velocity agree well with experimental date. The damage modes basically reflect experimental results. Penetration process and damage modes are studied in details by analyzing damage evolution along the x fiber and interface matrix. It shows that the simulations are in good agreement with experiments.