Penetration simulation of titanium plates

Penetration simulations have been made with a simulation program named AUTODYN. The simulations have been made with an armour piercing tungsten carbide projectile, with calibre 7.62 mm. The target is titanium alloy Ti6Al4V with the thickness 12.7 mm or 20.0 mm. The intention with the simulations is to investigate if it is possible to predict the experimental V50-velocity for the two plate thicknesses. If a Lagrange simulation is made with a fracture strain of 25% (which is valid for a uni-axial tension test), the V50-velocity would have been underestimated by approximately 18%. If as an alternative the J-C fracture model is used with appropriate parameters, the V50 would have been underestimated by approximately 14%. This is probably due to the underestimated influence from the strain rate on the flow stress.