The damage evolution and ignition mechanism of high explosives are of great importance in assessing the safety of munitions and guiding the design of munitions. In this study, the smoothed particle hydrodynamics (SPH) method is combined with a viscoelastic–viscoplastic-damage constitutive model and a hot spot model to explore the damage and ignition responses of high explosives under low-velocity impact. In particular, the sub-particle method is developed in the SPH method to combine the macroscopic constitutive model with the mesoscopic hot spot model. First, the damage evolution of a compressed plate containing a cavity and the ignition response of a single particle at a given pressure and strain rate are studied separately, and the simulation results are validated by experimental results and existing finite element method simulations. Subsequently, the impact shear and crack extrusion tests of high explosives with complex stress states are explored, respectively. For typical pressed PBX under impact-shear loading, a large damage region is formed in the high explosives due to the tensile stress formed by the meeting of rarefaction waves, and the initial ignition region is mainly located in the region where the outer edge of the rod is in contact with the high explosives and extends in a circular shape to the inside of the explosives. For typical pressed PBX under crack extruded loading, the damage region is mainly concentrated in the materials squeezed into the crack, and the initial ignition region is mainly located around the crack and gradually extends above the crack. The results indicate that the proposed SPH method is capable of modeling the damage and ignition responses of high explosives under complex stress states.

中文翻译：

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SPH法数值模拟低速冲击下烈性炸药毁伤及着火响应


烈性炸药的毁伤演化和着火机理对于评估弹药的安全性和指导弹药的设计具有重要意义。本研究将平滑粒子流体动力学（SPH）方法与粘弹性-粘塑性损伤本构模型和热点模型相结合，探讨高能炸药在低速冲击下的损伤和着火响应。特别是在SPH方法中发展了亚粒子方法，将宏观本构模型与细观热点模型结合起来。首先，分别研究了含空腔压缩板的损伤演化和给定压力和应变率下单个颗粒的着火响应，并通过实验结果和现有有限元方法模拟验证了模拟结果。随后，分别对复杂应力状态烈性炸药的冲击剪切和裂纹挤压试验进行了探索。对于典型的冲击剪切载荷下压制的PBX，由于稀疏波相遇形成的拉应力，烈性炸药内形成较大的损伤区域，初始着火区域主要位于炸药外缘区域。杆与烈性炸药接触并呈圆形延伸至炸药内部。对于典型的挤压PBX在裂纹挤压载荷作用下，损伤区域主要集中在挤入裂纹的材料中，初始着火区域主要位于裂纹周围并逐渐延伸到裂纹上方。结果表明，所提出的 SPH 方法能够模拟复杂应力状态下烈性炸药的损伤和点火响应。