【摘要】 冲击载荷下延性材料的损伤是材料中微空洞的产生和长大演化的结果.利用分子动力学模拟方法对延性金属单晶铜中单个空洞在动态加载下的演化发展进行了研究,得到了空洞增长过程中的应力分布及空洞增长演化随冲击强度变化的规律.模拟结果表明,动态加载下的前期压缩过程对后期拉伸应力场作用下的空洞增长演化特征有不可忽视的影响,微空洞增长的阈值则与单晶实验中层裂强度随拉伸应力作用时间减少而增加的趋势相一致.更多还原

【Abstract】 The evolution of micro-voids under dynamic loading mainly contributes to the dynamic damage of ductile materials. In this work, the evolution of a preexisting nano-void in single crystal copper is investigated by means of molecular dynamics (MD) simulation. The relation between the time evolution of complicated stress distribution and the void growth is obtained. The precompression process before the tension process has strong influence to the void growth. That high threshold makes the void grow coincides with the trend that a shorter tension duration will lead to a higher spallation strength, which was found in latest single crystal spallation experiment.更多还原