Explosively driven fragmentation simulation of the 90mm Mk8 HESH grenade with LS-DYNA

Abstract

This thesis presents the simulation of an explosively driven fragmentation of the 90 mm Mk8 HESH grenade using the software LS-DYNA. The objective is to build an useful model allowing to reduce the number of ex-perimental tests which are expensive. Also the calibration of the 34CrMo4 steel with a new Gurson’s based method is developed. Two calibrations for two material cards are conducted (piece wise linear plasticity and Gurson’s based method) with the software LS-DYNA. As a first step the Goto test consisting in a explosively driven fragmentation of a steel cylinder is simulated. The simulations appears to show a really good correlation in terms of number of fragments and their relative masses with the experimental data. The guarantee of a good visual aspect of the fragmentation of the steel cylinder is achieved by comparing high-speed camera pictures and the simulation at given times of the expansion. The final objective, the detonation and fragmentation of the 90 mm Mk8 HESH grenade is simulated. The simulations results are satisfying, the grenade shows a qualitatively good detonation and fragmentation behaviour during the whole process.