加载速率和加载位置对炸药缝隙扩展过程影响的数值模拟

Numerical Study on the Effect of Loading Rate and Loading Positionon the Crack Evolution of Explosive

为研究弱载荷作用下炸药起裂、裂缝扩展过程,分析加载条件对缝隙扩展的影响规律,研究基于钝感炸药的三点弯曲试验,采用考虑了材料的拉压异性、应变率效应,以及损伤失效的本构模型,开展了炸药起裂和裂缝演化过程的数值模拟研究,拟合了主要的计算参数,计算结果与试验数据符合较好,校验了计算模型及其适用性;数值模拟获得了炸药样品中裂缝产生和扩展过程的典型特征图像,分析了加载速率和加载位置对炸药裂缝扩展演化规律的影响。研究表明,初始裂缝尺寸越大,起裂越早;随着加载速率增大,起裂荷载也增大,反映了炸药样品的应变率效应;加载位置偏离初始裂缝位置时,对于不同加载速率情况,样品中的裂缝扩展演化路径差异很大,存在4种破坏模式。

In order to study the law of crack initiation,growth and evolution of explosives under weak load.The numerical simu‑lation of crack initiation and evolution of explosives was carried out by using the material model considering the phenomena of tensile and compressive anisotropy with strain rate effect.The numerical results are in good agreement with the test data,and the applicability of the numerical model is verified.The typical characteristic images of crack generation and evolution of explosives were obtained through a series of numerical simulations,and the effects of initial crack size,loading rate and loading position on the crack propagation process of explosives were also analyzed,which can provide reference for the analysis of damage and fracture process as well as the dynamic response of explosives.