7050凹槽铝板激光冲击强化残余应力分布与疲劳寿命

激光冲击强化（LSP）是改善结构疲劳性能的重要手段，传统数值模拟方法很难模拟复杂结构的多点冲击强化过程。本文利用一种连续动态冲击方法对7050凹槽铝板进行激光冲击强化数值模拟，得到了冲击后稳定的残余应力场，并与试验测量的残余应力相对比，验证了该方法的精度与较高效率。运用4种基于临界平面法的应变模型，最大正应变模型、最大剪应变模型、BM模型和SWT模型分别对未强化件和强化件进行疲劳寿命预测。完成了激光冲击强化件和未强化件的疲劳试验，得到其疲劳寿命。结果表明：寿命预测值与试验结果吻合较好；对未强化件进行平均应力修正后，前3种模型误差分别为31.2%、22.6%和40.7%，而SWT模型的计算结果过于保守；对强化件进行最大正应力修正后，前3种模型误差分别为1.84%、24.0%和46.4%，而SWT模型的计算结果过于危险。

Residual stress profile and fatigue life of 7050 aluminum plate with groove under laser shot peening

Laser Shock Peening (LSP) is an important means to improve the structural fatigue performance. It is difficult to simulate the multi-point impact process of complex structures by traditional numerical simulation methods. In this paper, a continuous dynamic impact method is used to simulate the LSP of 7050 aluminum plate with groove. The stable residual stress field after impacts is obtained. By comparing with the measured values of residual stress, the higher accuracy and efficiency of this method are verified. Four strain models based on the critical plane method, the normal strain model, the shear strain model, the BM model, and the SWT model are used to predict fatigue life of unreinforced and reinforced samples. The fatigue tests of strengthened and unreinforced samples are carried out and their fatigue lives are obtained. The results showed that predicted lives are in good agreement with experimental results. After mean stress correction for unreinforced sample, the errors of the first three models were 31.2%, 22.6%, and 40.7%, while the result of SWT model is obviously too conservative. After the maximum normal stress correction for strengthened sample, the errors are 1.84%, 24.0%, and 46.4%, while the result of SWT model is obviously too dangerous.