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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。
In this paper, two-dimensional molecular dynamics simulation of jet and damage phenomena. The intermolecular interactions are depicted by the Morse potential. The initial molecule is in equilibrium. To simulate the uneven surface of the metal, the free surface is concave form. Shock wave can be the first layer of molecules formed by the same speed motion (piston), also can be formed by the collision of the flywheel molecules. When the disturbance reaches the free surface, the surface molecules fly off at a greater rate to form a jet, while the material begins to suffer damage. The ratio of spray velocity to free surface velocity varies between 1 and 3 depending on the shock wave intensity, free surface angle and material properties. When the free surface half angle greater than 60 °, the jet disappears. The shock wave intensity below a certain limit, it does not appear jet. The threshold of this shock wave intensity is related to the free half-width size and material properties. For both jetted and non-jetted cases, the calculated results show the formation and growth of micropores.