为了优选激光冲击工艺参量以获得最大的表面残余压应力, 利用激光冲击和塑性变形理论推导出了激光冲击AZ31镁合金表面最大残余压应力公式, 并采用ABAQUS有限元软件分析了其激光冲击后的残余应力场。结果表明, 获得较大残余压应力场的激光冲击波载荷范围为1.2GPa～1.7GPa, 随着载荷的增加, 残余应力增加, 当载荷在1.4GPa～1.6GPa时, 最大残余压应力为125MPa左右; 冲击载荷在1.8GPa时, 出现轻微的“残余应力洞”现象; 而在大于1.9GPa时, 均出现明显的“残余应力洞”现象; 载荷p=1.474GPa时最大残余应力为-128.5MPa。理论推导和有限元分析结果基本一致。

To obtain maximum surface residual compressive stress by optimizing technological parameters of laser shock, the formula of residual compressive stress on the surface of AZ31 magnesium after laser shock process (LSP) was deduced from the theory of laser shock process and plastic deformation. Residual stress fields of AZ31 magnesium by LSP was simulated with ABAQUS software. Finite element analysis shows that laser shock wave pressure of optimal residual compressive stress field ranges from 1.2GPa to 1.7GPa. With the increase of load, residual stress on the surface of AZ31 magnesium increases. The maximum residual compressive stress is about 125MPa with loading range from 1.4GPa to 1.6GPa. There is a slight residual stresses hole phenomenon impact when load is 1.8GPa and a significant residual stresses hole phenomenon when load is more than 1.9GPa. When the load is 1.474GPa, the maximum residual stress is -128.5MPa. Experimental results are consistent with finite element analysis.