强冲击载荷下含杂质的纯铝中微孔洞长大的动力学行为

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了数值模拟。结果表明:微孔洞首先在杂质与基体的边界处成核,随后在局部严重塑性变形驱动下快速线性增长;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;材料屈服强度和初始杂质的大小对微孔洞相对的增长速率有明显的影响;当微孔洞长大阈值取屈服强度的3.5倍时,数值仿真结果与理论分析结果基本一致,这有助于进一步认识孔洞长大的动力学行为。

Dynamic Behavior of Void Growth in Aluminum with a Preexisting Flaw under Intense Impact Loading

By means of the explicit nonlinear dynamic finite element computer code LS-DYNA, the nucleation and growth of void in aluminum with a preexisting flaw under plate impact loading have been investigated. The results are as follows: firstly, the void nucleation occurs from the boundary of the preexisting flaw and the ductile matrix, and once the voids have been nucleated, they grow linearly through the localized plastic deformation; secondly, the growth rate of void radius increases linearly with the shock loading amplitude; thirdly, the yield strength and the size of the preexisting flaw have an obvious influence on the relative growth rate of void; finally, if the threshold stress of the void growth is set as 3.5 times of the yield strength, the simulation results agree reasonably well with the theoretical results, which is helpful for the further understanding of the void growth dynamic behavior.