冲击波加载下单晶铜动态破坏微观过程的分子动力学研究

Microscopic Simulation on Dynamic Failure Process of Single Crystal Copper under Shock Wave Loading Using Molecular Dynamics

  • 摘要: 采用嵌入原子势模型和分子动力学方法,模拟研究了冲击波加载下单晶铜动态破坏的微观过程和空洞成核及生长过程。根据原子中心对称参数变化给出了单晶铜动态破坏的微观过程,通过不同碰撞速度的模拟,讨论了冲击波加载下破碎区内物质形态分布的变化,给出了材料破坏深度的变化规律。研究发现纳米空洞在完整单晶铜中随机成核,空洞成核后,空洞表面的应力集中和原子活化易形成位错源,各种不同类型的位错的生长使空洞逐渐长大,空洞长大到一定尺寸后,邻近空洞相互作用贯通形成更大尺寸的空洞,这种空洞贯通效应造成了材料内部的宏观层裂及失效。

     

    Abstract: The microscopic process and void nucleation and growth process of the dynamic failure of single crystal copper under shock wave loading were investigated using embedded atom potential model and molecular dynamics methods. According to the change of the atomic center symmetry parameter, the microscopic process of the dynamic failure of the single crystal copper was given. By simulating different impact velocity, the changes in the material distribution area broken under shock wave loading were discussed, and the variation of material damage depth was given. The results show that the random nucleation of nano voids is in the complete single crystal copper. The stress concentration on the voids surface and the activation of the atom are easy to form the dislocation source. The voids gradually grow up because of the growth of different types of dislocation. Adjacent voids then interact and merge to form larger size ones. When the size and density of voids reach a certain critical value, the coalescence of voids forms macro fractures and failure within materials.

     

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