Simulations of semi-infinite penetration

Idealised materials deformation models have been used in conjunction with a n analytical approach to study the penetration of kinetic energy penetrator s into semi-infinite targets. Numerical simulations were carried out using the DERA cAst Euler hydrocode. Deformation models used a modified form of t he Armstrong-Zerilli bcc form [1, 2]. The projectile model included the phy sical and equation of state properties for a dense alloy with deformation d efined by incorporating idealised constants in the model. It was shown that there is little variation in penetration depth within the range of propert ies likely to be achievable in practice. High strain rate sensitivity produ ces very high transient strength which provides essentially rigid body pene tration. Equivalent performance was difficult to achieve by increasing the static strength alone because of the thermal softening contribution. In con trast thermal softening, of the right type, allows the curvature and constr aint in the penetrator nose to produce a small head in a different way. In this case the strength of deformed material is decreased significantly allo wing the head to curve around sharply, creating only a small diameter cavit y in the target.