A computational study of the influence of thermal softening on ballistic penetration in metals

A two-dimensional axisymmetric computational study of the penetration of a tungsten heavy alloy (WHA) rod into a 6061-T6 aluminum target has been perf ormed using a Lagrangian formulation. Adaptive remeshing has been used to a lleviate the problem of excessive distortion of elements which occurs durin g large deformation studies (such as ballistic penetration). Strain hardeni ng, strain-rate hardening and thermal softening in both the penetrator and target materials are taken into full consideration. The computed depth of p enetration (DOP), residual penetrator length and maximum crater diameter ma tch very well the experimental results reported by Yadav and Ravichandran ( Int. J. Impact Eng., Submitted for publication) for an impact velocity of 1 100 m/s. Computer simulations reveal that in the absence of failure mechani sms (such as shear banding), introduction of thermal softening in the penet rator material decreases its depth of penetration in a metal target, when c ompared to a penetrator material which does not soften thermally. These res ults are in contrast to the recent work of Rosenberg and Dekel (Int. J. Imp act Eng. 21 (1998) 283-296) and a plausible explanation for this discrepanc y is presented. (C) 2001 Elsevier Science Ltd. All rights reserved.