强冲击载荷下纯铝中微孔洞长大行为

Dynamic Behavior of Void Growth in Aluminum under Strong Impact Load

本文采用LS-DYNA瞬态动力学有限元程序,对平板撞击加载下含初始杂质的纯铝样品中微孔洞的成核与长大进行数值实验研究,结果表明:1)微孔洞首先从杂质与基体的边界处开始成核,随后在局部严重塑性应变驱动下快速线性增长;2)微孔洞半径的增长速率与冲击加载强度两者之间近似成线性关系;3)材料屈服强度和初始杂质的大小都对微孔洞相对增长的速率有明显的影响;4)在微孔洞长大阈值取3.5倍的屈服强度条件下,数值仿真结果与理论分析结果基本一致。

By using an explicit nonlinear dynamic finite element code LS-DYNA,the nucleation and growth of void in aluminum with preexisting impurity under plate impact loading were simulated.The simulated results show that the void nucleation starts from the boundary of preexisting impurity and ductile matrix,which grows rapidly and linearly owing to local plastic deformation;the growth rate of the void radius increases linearly with the shock load;the yield strength and size of preexisting impurity have an obvious influence on the relative growth rate;if the threshold stress of the void growth is taken as 3.5 times of the yield strength,the simulated results coincide better with the theory results.