Peridynamic modeling of dynamic damage of polymer bonded explosive

Abstract

Dynamic damage response of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) based polymer bonded explosive (PBX) is investigated by using recently developed three dimensional Peridynamic (PD) method, allowing natural evolution of defects such as cracks or voids. An in-house PD codes are developed and verified by comparing with published results on Kalthoff-Winkler (KW) and crack branching benchmark tests. Numerical modeling of PBX is constructed via random micro-modulus approach, capable of capturing inherent microstructural heterogeneity of PBX materials. The simulation results indicate that damage process depends on both impact speed and interfacial property. Damage mode index (DMI), defined as the ratio of HMX-HMX damage to the summation of Binder-Binder and HMX-Binder damage, is proposed to quantify competitive damage mechanisms between trans- and inter-granular damage. The analyses of DMI exhibit that the inter-granular damage is dominant for the low adhesive strength of interface. However, the trend of trans-granular damage increases with increasing impact speed. The trans-granular damage mode becomes dominant for the high adhesive strength of interface. But the trend of inter-granular model increases with increasing impact speed. The current research highlight the competitive mechanisms of two typical damage modes as a function of material property and external loading conditions in a quantitative manner, providing additional insight into the damage mechanisms of PBX under impact loading.