NUMERICAL AND EXPERIMENTAL-STUDY OF THE FORMATION OF ADIABATIC SHEAR-BAND

The stepped specimen under impact loading was chosen to study the init iation and growth of the adiabatic shear band. Explicit time integrati on finite element code with rate dependent plasticity material model w as utilized for numerical study. The material model includes the effec ts of strain hardening, strain rate hardening, and thermal softening. For experimental study, specimen made of 4340 steel and compression Ho pkinson's bar was used to apply controlled short compression pulse. Af ter the impact loading, the specimen was cut, polished, etched, and ex amined under the optical microscope. Very sharp shear band apparently formed by localized deformation was observed. It is shown that overall shape and direction of adiabatic shear band coincide with results of the numerical calculation.