激光冲击铜薄膜的应力波传播特性模拟分析

Simulation of propagation characteristics of stress wave in copper films with laser shock processing

为了研究冲击波的传播特性,采用有限元分析方法模拟不同参量激光冲击铜薄膜的过程,结合应力波理论分析了膜-基系统的动态应力波传播特性。结果表明,激光能量为30m J时,冲击波为弹性波,薄膜在单次冲击作用下,其内质点速率最大为-0.018mm/μs,3次冲击作用下,薄膜内部质点速度与残余应变变化较小;激光能量为120m J时,冲击波为弹塑性波,3次冲击比单次冲击质点最大速率减小了26.44%,残余应变深度增加了35.48%。这对研究冲击波传播具有指导意义。

In order to study the propagation characteristics of shock wave, shock processing of copper films under the different processing parameters was simulated with finite element software. Propagation characteristics of dynamic stress wave in film-substrate system were analyzed by using stress wave theory. The results show that when the laser energy is 30mJ, shock waves are elastic. The maximum velocity of particles in thin film with the single shock is -0. 018mm/μs, the change of the velocity and the residual strain of particles in films is little with three shocks. When laser energy is 120mJ, shock waves are elastic-plastic. The maximum velocity of particles and the largest depth of the residual strain in the films with three shocks are respectively 26. 44% lower and 35. 48% higher than those with single shock. These have guiding significance to the study of propagation characteristics of shock wave.