借助ABAQUS软件建立了微尺度激光冲击强化(micro-scale laser shock peening, μLSP)过程的有限元模型, 对T2纯铜的μLSP过程进行了数值模拟, 分析了μLSP过程中纯铜的位移、塑性应变和等效应力的动态响应情况以及残余应力的分布规律。结果表明, 冲击波作用到纯铜表面后, 极短时间内便可达到纯铜的动态屈服极限。纯铜表面的位移影响区域直径约为激光光斑的2倍, 并在27 ns时达到位移最大值约0.85 μm。随着冲击波压力的加载, 纯铜产生加工硬化, 塑性应变和等效应力的最大值均出现在加载区域内部的近表层处, 分别约为0.062 MPa和297 MPa。μLSP后纯铜表面激光辐照区域主要表现为残余压应力, 最大值约为199 MPa, 影响深度达40 μm。在激光辐照区域表面边缘存在一定的残余拉应力, 产生“残余应力洞”。同时, μLSP工艺试验结果与数值模拟结果基本一致, 从而验证有限元模型的合理性与可靠性。

A finite element model of micro-scale laser shock peening (μLSP) was established utilizing ABAQUS.Process of μLSP of T2 pure copper was numerically simulated. The dynamic response of displacement, plastic strain, and equivalent stress as well as the distribution rule of residual stress during μLSP were analyzed. The results show that the dynamic yield limit of copper can be reached in a very short time after the shock wave acting at the surface. The diameter of the displacement-affected region at the surface of copper is about twice the laser spot diameter, and the maximum displacement of around 0.85 μm is achieved at 27 ns. With the increase of shock wave pressure, work hardening occurs in copper, and the maximum plastic strain and equivalent stress of about 0.062 and 297 MPa appear at the near-surface of the loaded region. The laser irradiated region of copper mainly shows residual compressive stress after μLSP which is about 199 MPa and has an influence depth of 40 μm. Residual tensile stress exists at the edge of laser irradiated region, indicating the appearance of “residual stress hole”. Meanwhile, the experimental results of μLSP are basically consistent with the numerical simulation results, which verify the reasonability and reliability of the finite element model.