为研究不同边界约束条件对薄板多点激光喷丸诱导残余应力和塑性变形的影响, 采用数值模拟和试验结合的方法对7075铝合金薄板激光喷丸处理进行研究, 对比分析了板料在底部全约束和两端夹持两种边界约束条件下的变形形貌和残余应力分布。结果表明: 激光喷丸后, 板料冲击区域均产生微凹坑; 底部全约束的板料经激光喷丸后, 未发生整体变形, 仍然保持平整状态, 而两端夹持的薄板喷丸区域发生了整体向上的凸起变形。两种边界约束条件下, 最大残余压应力均出现在板料的冲击表面; 底部全约束时的最大残余压应力为299.0 MPa, 大于板料两端夹持时的251.6 MPa。在厚度方向上, 其残余应力分布也存在着明显差异, 底部全约束时, 厚度方向上的残余应力分布形式为“压应力-拉应力”, 而两端夹持时的分布形式为“压应力-拉应力-压应力”。

The numerical simulations and experiments were employed to investigate the effect of boundary constraint conditions of thin plate on residual stresses and plastic deformation induced by laser shock peening. Two boundary conditions, bottom fully constrained and both ends clamped, were used to compare residual stresses distribution and deformation morphology of 7075 aluminum plates after impacted by multiple laser shock peening. The results show that micro-dents were generated in impacted regions of both cases after treated by laser shock peening. The plate still kept flat without cross-sectional deformation when its bottom surface was fully constrained, while the overall upward convex deformation was produced in the impacted region of plate with both ends clamped. Moreover, the maximum compressive residual stresses existed on the surface of both cases, which was 299.0 MPa in the plate with bottom fully constrained and 251.6 MPa in the other case. Different styles of residual stresses field are also found in the thickness direction. The residual stresses from the impacted surface to the bottom was "compressive residual stresses -tensile residual stresses" in the plate with bottom fully constrained, while it was "compressive residual stresses-tensile residual stresses-compressive residual stresses" in the plate with both ends clamped.