单晶铜中冲击波阵面结构的数值模拟研究

 用分子动力学方法模拟计算了在初始温度为0 K时单晶铜中的冲击波结构，相互作用势采用铜的嵌入原子势（EAM），模拟计算结果表明即使是在初始温度为0 K的FCC晶体中，冲击波波阵面后的区域也会向平衡态演化。局域分析表明冲击波阵面后区域的压力、粒子速度、应变和温度随时间逐步变化到稳定态，在所研究的冲击波强度（约262 GPa）下，波后区域的平均压力、粒子速度、应变均在约1 ps内逐渐上升并达到稳定值。动能温度在波阵面处始终为最大值，随着冲击波的传播，波后非零温度区域逐渐扩大，不同时刻的粒子速度分布函数说明波后区域逐渐向热力学平衡态演化，并最终达到热力学平衡，进一步的分析说明局域平衡是系统向平衡态演化的基本过程。

Numerical Simulation of Shock Wave Structure in Single Crystal Copper

The structure of shock wave in single crystal copper has been studied by means of molecular dynamics(MD) method with a realistic embedded atom potential at initial condition of zero temperature.The simulation results indicate that the after-shock state will evolve to thermodynamic equilibrium state even initial state is zero temperature.By means of local analysis and calculation,time history of the distribution of pressure,particle velocity,strain and kinetic temperature after the shock front were obtained.The pressure,particle velocity,and strain increase and arrive at the stable condition within time period about 1 ps when shock pressure is about 262 GPa.The kinetic temperature always keeps maximum value in shock wave front and the nonzero temperature region broadens behind the shock wave as time passes by.After evolution of a critical time,the particle velocity in the after-shock region reaches a typical Maxwell distribution which means it reaches equilibrium state.The further(analysis) indicates that local equilibrium is an elemental course when the whole system evolves to thermodynamic equilibrium state.