激光冲击强化过程中蒸气等离子体压力计算的耦合模型

A coupling model for computing plasma pressure induced by laser shock peening

首先基于系统能量守恒条件,提出了一种计算蒸气等离子体压力的一维耦合计算模型。模型中不仅考虑了蒸气等离子体界面压力与质点速度的非线性效应,同时也考虑了界面烧蚀所致的运动速度,将蒸气等离子体的膨胀与约束介质的变形耦合。在耦合模型的基础上,采用显式差分计算程序与显式有限元计算程序LS-DYNA互相迭代求解的方法,对不同激光功率密度分布下的蒸气等离子体压力进行了计算。结果表明,计算结果与实验测量结果具有很好的一致性,证明了计算模型的合理性。

Pressure profile of plasma is one of the most important factors for the effects of laser shock peening. In the present research, a one-dimensional coupling model for computing plasma pressure is established based on energy conservation condition in the system, in which the interface vaporization velocity and the nonlinear relationship between the shock pressure and the surface particle velocity are considered. Then, the explicit difference program and the LS-DYNA package are used to calculate the plasma pressure for different laser power density with given time-history profile. The simulation re- sults show a good agreement with the experimental results, which indicates the consistency of the ana- lytical model. Therefore, an effective method is provided to predict the plasma pressure induced by la- ser shock peening.