Direct measurement of material dynamic strength under high pressure using magnetically driven pressure-shear loading

Abstract

Material strength measurement under high pressure is a long goal of impact dynamics. In this work, we report a new method for directly measuring material dynamic strength under high pressure, viz. magnetically driven pressure-shear loading technique. The relations of deviatonic stresses and yield stress under pressure-shear loading were analyzed, and simple functions of deviatonic stresses and yield stress were obtained under complex stress state. Using LS-DYNA code, evolutions of deviatonic stresses and Von-Mises stress in sample under ramp wave pressure-shear loading were simulated, and calculation method of material strength is given. Based on numerical simulations results, magnetically driven ramp wave pressure-shear experiments were conducted on pulsed power generator CQ-4, with established quasi-static magnetic field generator and transverse velocity measurement techniques, to explore dynamic strength of aluminum at high pressure. Reliable experimental results are obtained. The results show that, as a potential new technique, magnetically driven pressure-shear combination loading has great application prospect in material dynamic strength measurement under high pressure.