7050凹槽铝板激光冲击强化残余应力分布与疲劳寿命

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.