基于内聚裂纹模型的高聚物粘结炸药模拟材料动态断裂行为研究

Research on Dynamic Fracture Behavior of Polymer Bonded Explosive Simulant Based on Cohesive Crack Model

对某高聚物粘结炸药(PBX)模拟材料的动态拉伸断裂行为进行研究。针对该材料开展了基于霍普金森压杆的动态带预制裂纹半圆盘弯曲实验,并结合高速摄像与数字图像相关方法,得到了试样动态破坏过程中的位移场和应变场。基于内聚裂纹模型,对其动态拉伸破坏过程进行了数值模拟。数值模拟与实验结果进行对比后发现,拉伸应力曲线、试样破坏前后变形场等结果符合较好。根据数值模拟结果,分析了PBX试样在动态预制裂纹半圆盘弯曲实验过程中的裂纹扩展演化规律,得到裂纹宽度比实验结果偏小约15%的结论。

The dynamic tensile fracture behavior of polymer bonded explosive simulant was investigated.The experimental test was performed on notched semi-circular bending（NSCB） samples of the material by using the split Hopkinson pressure bar（SHPB） apparatus.With the aide of a high-speed camera,the dynamic displacement and strain field during the dynamic fracture process were obtained by the digital image correlation（DIC） technique.Based on cohesive crack model（CCM）,the numerical simulation of the same conditions was performed.Compared with the results obtained by simulation and experiment,the good agreement was found for the time history of tensile stress and the displacement and strain fields during dynamic fracture.The behavior of crack propagation of PBX during NSCB test wasanalyzed by the CCM.Furthermore,the width of crack in NSCB sample is about 15 % smaller than the experimental results.