GH4169高温合金激光冲击强化后残余应力场分析

Analysis of Residual Stress Field Induced by Laser Shock Peening on GH4169 Superalloy

关键词:  激光冲击强化  GH4169高温合金  有限元仿真  残余应力场  Johnson-Cook模型

Key words:  Laser shock peening  GH4169 superalloy  Finite element simulation  Residual stress field  Johnson-Cook model

摘要:

为了提高大面积激光冲击强化数值模拟效率及计算精度，本文采用Johnson-Cook模型，分析了激光冲击作用下镍基高温合金GH4169的残余应力分布，并设计试验进行对比。结果表明，单点冲击条件下，表层残余应力最大值随着激光脉冲能量的增大而增大，残余应力最大值在空间中的分布形成一个残余应力“波谷”。多点冲击条件下，残余应力最大值也与激光脉冲能量呈正相关，沿冲击点中心路径的表面残余应力分布在开始阶段表现出类似“正弦”特征。对试验件进行了残余应力测试，在激光脉冲能量为3J，4J，5J时的残余应力平均值分别为627.45MPa，776.94MPa，860.25MPa，分别提升了24%和11%，在三种脉冲能量下，残余应力测试值均与有限元模拟结果较为接近。

Abstract:

In order to improve the efficiency and accuracy of large-area LSP numerical simulation， the distribution of residual stress field of GH4169 superalloy after LSP was studied by using the Johnson-Cook model and was used to compare with the experiments. It was shown that the maximum residual stress of the surface layer increases with the increase of laser pulse energy in the case of single point impact， and its distribution in space forms a residual stress “valley”. Under multiple point impact conditions， the maximum residual stress is also positively correlated with the laser pulse energy. The distribution of surface residual stress along the center path of the impact point exhibits a “sinusoidal-like” characteristic at the beginning. When the laser pulse energy was 3J， 4J， and 5J， the average residual stress test results was 627.45MPa， 776.94MPa， and 860.25MPa， which increased by 24% and 11%， respectively， they are all close to the finite element simulation results under the three pulse energies.