Based on the two-dimensional finite element simulation with commercial MSC software, the fracture observation with scanning electron microscope and theoretical analysis, the stress and strain status of X80 pipeline steel during the impact process and the micro-mechanism of inclusion morphology and size on the formation of voids were investigated. The results show that the square inclusions are more sensitive to plastic strain energy density (PSED) than the circular inclusions with the increase in inclusion size. The maximum equivalent strain and the minimum stress triaxial factor (R_σ) of the circular inclusions appear at the interface of 45° and 135° while that of the square inclusions appear at the sharp interface. And the circular inclusions have much lower strain concentration and damage value than the square inclusions, which make them difficult in separating from the matrix materials. The first generation of voids is mainly formed at the interface of the maximum PSED and the minimum R_σ, while the second generation of voids is formed at a certain distance from the interface with the second large PSED. Small-sized inclusions tend to produce the larger size of dimples and absorb more impact energy compared with large sized inclusions.

基于商用MSC软件的二维有限元模拟，扫描电子显微镜的断裂观察和理论分析，X80管线钢在冲击过程中的应力和应变状态以及夹杂物的形态和尺寸的微观机制。研究了空隙的形成。结果表明，随着夹杂物尺寸的增加，方形夹杂物比圆形夹杂物对塑性应变能密度（PSED）更敏感。最大等效应变和最小应力三轴因子（ř _σ）的圆形夹杂物出现在45°和135°的界面处，而方形夹杂物的出现在尖锐的界面处。而且，圆形夹杂物的应变集中度和损伤值远低于方形夹杂物，这使得它们很难与基质材料分离。所述第一空隙的产生主要形成在最大PSED和最小的接口- [R _σ，而在从与所述第二大PSED界面一定距离形成在第二空隙的产生。与大尺寸夹杂物相比，小尺寸夹杂物倾向于产生更大尺寸的酒窝并吸收更多的冲击能量。