论文标题
空隙间距和材料尺寸效应对空间间流量定位的相互作用
Interaction of void spacing and material size effect on inter-void flow localisation
论文作者
论文摘要
由于生长和微米尺度的合并，多孔金属中的延性断裂过程不仅受施加的应力状态的影响，而且还受到空隙的分布和材料大小效应的影响。这项工作的目的是了解一系列施加的应力状态的渐变间距（或韧带）的相互作用以及所得梯度诱导的材料大小对空隙结合的影响。为此，执行了嵌入在应变梯度增强材料矩阵中的离散空隙的单位细胞模型的三维有限元计算。计算是针对一系列初始脉冲韧带大小的范围和以应力三轴性和LODE参数为特征的应力状态。我们的结果表明，在没有应变梯度对材料反应的影响的情况下，降低了膜间韧带的大小会导致空隙结合的倾向增加。但是，在应变梯度增强的材料基质中，应变梯度使韧带中的材料变硬，并降低了空间韧带尺寸对空隙聚结倾向的影响。
The ductile fracture process in porous metals due to growth and coalescence of micron scale voids is not only affected by the imposed stress state but also by the distribution of the voids and the material size effect. The objective of this work is to understand the interaction of the inter-void spacing (or ligaments) and the resultant gradient induced material size effect on void coalescence for a range of imposed stress states. To this end, three dimensional finite element calculations of unit cell models with a discrete void embedded in a strain gradient enhanced material matrix are performed. The calculations are carried out for a range of initial inter-void ligament sizes and imposed stress states characterised by fixed values of the stress triaxiality and the Lode parameter. Our results show that in the absence of strain gradient effects on the material response, decreasing the inter-void ligament size results in an increase in the propensity for void coalescence. However, in a strain gradient enhanced material matrix, the strain gradients harden the material in the inter-void ligament and decrease the effect of inter-void ligament size on the propensity for void coalescence.
