中文摘要：

为了研究不同应力比下激光喷丸强化（LSP）对6061T6铝合金疲劳裂纹扩展性能的影响，采用有限元软件ABAQUS和疲劳分析软件MSC．Fatigue相结合，对应力比为0．1、0．3、0．5条件下的6061-T6铝合金紧凑拉伸（CT）试样进行了激光喷丸强化疲劳裂纹扩展的数值模拟，分析残余压应力对高低应力比下的裂纹闭合效应，探索不同应力比对激光喷丸强化疲劳寿命增益的影响。结果表明，经过激光喷丸后，3种不同应力比下的疲劳裂纹扩展速率较未处理试件都有一定的降低；应力比的取值对激光喷丸后CT试样的疲劳寿命有显著影响，应力比越小，激光喷丸对CT试样疲劳寿命的增益影响越明显。

英文摘要：

In order to investigate the effect of laser shot peening （LSP） on fatigue crack propagation of 6061-T6 aluminum alloy under different stress ratios, finite element software ABAQUS and fatigue analysis software MSC. Fatigue are used to establish the prediction model to analyze the effects of different stress ratios （R = 0.1, 0.3, 0.5） on crack propagation induced by LSP. The effects of residual compressive stress on the crack closure under different stress ratios are studied and the increase of fatigue life is predicted. The results show that fatigue crack growth rate decreases after LSP, compared with the untreated sample under three stress ratios. The value of stress ratio significantly affects the fatigue life of compact tension （CT） specimen after laser shot peening, however, the lower value of stress ratio is, the more the increase in fatigue life attained by LSP is.