爆炸加载下金属壳体膨胀断裂过程中的关键物理问题

爆炸加载下金属壳体膨胀断裂过程是武器研制领域关注的重要课题，该过程包含着丰富的力学与材料学基础科学问题，吸引着众多学者的长期关注。本文中通过分析爆炸加载下金属壳体膨胀断裂过程，明确了其中蕴含的3个关键物理问题:材料动态拉伸本构、壳体膨胀断裂机理和破片尺寸控制机理，综合分析了这3个关键物理问题的研究现状与趋势。

Key physical problems in the expanding fracture of explosively driven metallic shells

The expansion fracture process of metallic shells under explosive loading is an important topic in fields of weapon design. This process contains a wealth of basic science problems in materials science and mechanics, which has attracted the long-term attention of many scholars. Based on the analysis of the expansion fracture behavior of metal shells under explosive loading, three key physical problems were clarified: dynamic tensile constitutive law of metals, expansion fracture mechanism of shells and mechanism of fragment size. The current status and research trends of the three physical problems were comprehensively analyzed. For the aspect of dynamic tensile constitutive law of metals, it is need to develop some new experimental methods to stretch the material at higher strain rates, to develop the experimental techniques of expanding cylindrical and spherical shells for studying the dynamic tensile constitutive relationship of materials under three dimentional stress state, and to develop the transient acceleration measurement technique and the interpretation method of expansion ring experimental data. For the expansion fracture mechanism, the main development trends are to develop the in-situ or freezing diagnostic techniques to capture key parameters in the fracture process of shells, to use the statistical method to study the fracture behavior, to reveal the essential mechanism of the fracture mode transition and the Ivanov plastic peak phenomena, and to study the mechanism of expanding fracture shells at the micro level. For the mechanism of fragment size, it is need to study the relationship between the fragment size and all the potential control variables with the experimental and modeling method, to analyze the relationship between the micro heterogeneity of the material and the statistical distribution of the fragment size by taking the probability distribution of fracture strain as a bridge, and to analyze the influence of two-dimensional or three-dimensional effects on fragment size distribution and develop new models.