低速撞击下 pbx 炸药黏弹塑性细观损伤点火模型研究

To investigate the mechanical deformation, damage and thermal response of polymer bonded explosive PBX-9501 under low velocity impact, a nonlinear viscoelastic plastic meso-damage mechano-chemical coupling model based on viscoplasticity evolution equation and micro-crack nucleation and evolution mechanism under complex stress state was developed. By analyzing the influence of mechanical deformation and damage on the macro and micro temperature increase of explosive in the low velocity impact test, the dominant ignition mechanism and ignition velocity threshold of explosive were determined. It is found that PBX-9501 explosive exhibits large deformation and crushing response at an impact velocity of 59 m/s. The damage degree induced by microcracks and microvoids are the highest at the top, and the micro-crack mechanism plays an important role in the temperature increase of hot spot; with the increase of impact velocity, the microcrack mechanism is still the dominant ignition mechanism and the critical velocity of ignition of PBX-9501 is predicted to be 120～125 m/s.