冲击作用下纳米孔洞动力学行为的多尺度方法模拟研究

本文利用多尺度方法研究了包含孔洞金属材料在冲击加载条件下的动力学行为. 该多尺度方法结合了分子动力学和有限元方法，分子动力学方法运用于局部缺陷区域，而有限元方法运用于整个模型区域，两种方法之间使用桥尺度函数进行连接. 计算结果既包括了系统宏观的物理信息，如应变场、应力场、温度场等，也得到了微观原子的物理信息，如原子能量和位置坐标等. 结合以上的模拟结果，发现孔洞的坍塌与材料屈服强度和冲击强度有关，而孔洞坍塌和坍塌过程中对微喷射原子的压缩过程是形成局部热点的主要原因. 同时也发现孔洞坍塌形成的位错和局部热点可以导致局部绝热剪切带更容易形成.关键词：微孔洞热点冲击加载多尺度方法

Multi-scale simulation of the dynamic behaviors of nano-void in shocked material

In this paper, the multi-scale numerical simulation method was used to simulate the dynamic behaviors of nano-void in metal Al under shock loading. This method couples the molecular dynamics method used in local defect domain and the finite element method used globally by using a bridge-scale function. Based on the calculated strain field and temperature field and atom positions, we reveal that the collapse of nano-void depends on the yield strength of materials and shock loading strength. And compression process of void is the main reason of formation of local hot spot. Meanwhile, the dislocation and hot spot induced by void collapse lead to the easy formation of the local adiabatic shear band.