平顶光束激光冲击2024铝合金诱导残余应力场的模拟与实验

对平顶光束激光冲击2024铝合金诱导的残余应力情况进行了有限元模拟与实验研究。改进了平顶光束诱导冲击波的压力分布模型,并将该模型用于残余应力场的有限元模拟。在实验室环境下获得了适合用于激光冲击的高质量平顶光束,并使用该光束进行激光冲击2024铝合金的实验,实验结果和模拟结果基本一致。研究发现平顶光束冲击2024铝合金有如下特点:存在一个阈值,当激光冲击波压力小于该阈值时,影响区内残余应力场近似均匀分布;当冲击波压力大于该阈值时会引起"残余应力洞",但该"残余应力洞"内部近似均匀分布。在深度方向上,塑性影响深度和最大残余应力深度随激光冲击波压力的增加而增加。

Simulation and Experimental Study on Residual Stress Field of 2024 Aluminum Alloy Induced by Flat-Top Laser Beam

Finite element simulation and experimental study on residual stress distribution of the 2024 aluminum alloy induced by flat-top laser shock are reported. Pressure distribution model of shock wave induced by flat-top laser beam is improved and applied to finite element simulation of residual stress field. High-quality flat-top laser beams, which are suitable for laser shock processing (LSP), are aquired and used for experiments of laser shock processing of 2024 aluminum alloy. The experimental results are consistent with the simulation results. The results show that the characteristics of flat-top laser beam shock processing of 2024 aluminum alloy can be concluded as follows. Residual stress distribution is almost even in the surface of impacted area of 2024 aluminum alloy when shock wave pressure is below a certain level; and once it exceeds this level, shock wave will produce residual stress hole, however, the distribution style is nearly equal. The results in the depth direction indicate that the impacted depth and the depth of maximum residual stress increase with laser shock pressure increasing.