材料微喷射和动态损伤的分子动力学研究  

MOLECULAR DYNAMICS RESEARCH OF EJECTION AND DAMAGE OF METALS INDUCED BY REFLECTION OF SHOCK WAVE AT FREE SURFACE

作　　者：张景琳[1] 王继海[1] 杨淑霞[1] 

机构地区：[1]北京应用物理与计算数学研究所计算物理实验室,100088

出　　处：《计算物理》1993年第3期318-324,共7页Chinese Journal of Computational Physics

基　　金：国家自然科学基金

摘　　要：本文用二维分子动力学方法模拟喷射和损伤现象。分子间的相互作用用Morse势描绘。初始分子位于平衡态。为模拟加工不平的金属表面,使自由面为凹角形式。冲击波可由第一层分子的等速运动(活塞)形成,亦可用分子组成的飞片碰撞形成。当扰动到达自由表面时,表面分子以更大的速度飞离而形成喷射,同时材料内部开始受到损伤。喷射的速度和自由面速度之比变化于1到3之间,它依赖于冲击波强度、自由表面夹角和材料性质。当自由面半角大于60°时,喷射消失。而冲击波的强度低于某极限值时,亦不出现喷射。这个冲击波强度的阈值和自由面半角大小以及材料性质有关。对于有喷射和无喷射的两种情况,计算结果都显示了微孔洞的形成和增长的过程。The two-dimensional molecular dynamics calculation is used to simulate ejection and damage phenomena. The intermolecular force is described by Morse potential. Molecules are initially located in equilibrium position and spaced so that the free surface has an angle shape for simulating real machined surface. Shock wave may be produced by motion of first layer of molecules (piston) or by impact of flyer of molecules. When the disturbance arrives at free surface, the boundary molecules start to run away from it with large velocity and the inside damage begins. The ratio of ejection velocity to the surface one changes from 1 to 3 and it is dependent on the shock strenth, surface angle and material property. When the semiangle is bigger than 60°, the boundary molecules can not run away from others, i.e. the ejection disappears. It also disappears when shock strength is lower than a limit value dependent ont he surface angle and material. In the both ejection and jetless cases the calculation shows the process of microvoid formation and growth.

关 键 词：分子动力学 材料 模拟 喷射 损伤 

分 类 号：TB303[一般工业技术—材料科学与工程]