AISI-304奥氏体不锈钢喷丸残余应力的有限元模拟

目的针对喷丸有限元模拟中多数模型的弹丸数量较少,不能准确反映喷丸过程中弹丸位置的随机性及喷丸覆盖率对残余应力场影响的问题,对喷丸过程的有限元模拟技术进行优化。方法基于大型有限元分析软件ABAQUS,使用python编程语言对弹丸在三维空间中的分布进行随机化处理,建立了随机多弹丸喷丸AISI-304奥氏体不锈钢的有限元模型。在喷丸覆盖率大于100%的条件下,模拟分析了喷丸工艺中弹丸的数量、尺寸和弹丸的速度对残余应力场的影响,结合试验对有限元模型的合理性进行了验证。结果增加弹丸数量可提高残余压应力层的厚度和残余压应力的最大值,当弹丸数量为90颗时,残余压应力场接近饱和;增加弹丸速度,靶材残余压应力的峰值、表面应力值及残余压应力场的深度值增大,残余压应力峰值出现的位置基本不变;增大弹丸的直径,靶材残余压应力峰值、峰值的位置、表面应力值及残余压应力场的深度值均明显增大。结论喷丸残余应力的试验测量结果和有限元模拟结果吻合,模型合理。

Finite Element Simulation of Residual Stress of Shot Peening on AISI-304 Austenitic Stainless Steel

The work aims to optimize the finite element simulation technology of shot peening technology since limited shots are used by most models in finite element simulation of shot peening, randomness of shot position and the effects of shot peening coverage to residual stress field are not accurately reflected. By virtue of a large-scale finite element analysis software ABAQUS, python programming language was used to randomize the distribution of shots in three-dimensional space and finite element model of random multi-shot shot peening was established. Provided that coverage rate of shot peening exceeds 100%, effects of shot quantity, size and velocity of shot peening technology on residual stress field were analyzed and simulated, and the rationality of the finite element model was verified by experiment. Thickness of compressive residual stress layer and the maximum residual stress could be increased by adding shots. The residual stress field was nearly satured when there were 90 shots. As the shot velocity increased, the peak value of residual stress on target, surface stress value and the depth of residual stress field increased and the site where residual stress peak was present kept unchanged. As the shot diameter increased, peak value of residual stress on target, surface stress value and the depth of residual stress field increased significantly. The measurement results of shot peening residual stress test are consistent with that of finite element simulation and the finite element model is reasonable.