铝合金结构腐蚀疲劳裂纹扩展与剩余强度研究

 在3.5%NaCl腐蚀溶液环境下对含中心孔LY12 CZ铝合金紧固件的疲劳裂纹扩展进行了试验研究，得到3种不同频率下紧固件的腐蚀疲劳裂纹扩展曲线。试验结果说明，随着频率的增加，腐蚀疲劳裂纹扩展速率逐渐降低，腐蚀溶液中疲劳裂纹扩展速率比在空气中大。以试验数据为基础，结合裂纹扩展分析软件AFGROW，提出一种可以用数值方法模拟腐蚀疲劳裂纹扩展的方法，模拟结果和试验结果符合较好。对紧固孔试验件利用2种失效模式进行了剩余强度分析，得到腐蚀环境下紧固孔结构的剩余强度曲线。

Investigation on Corrosion Fatigue Crack Growth and Residual Strength of Aluminum Alloy Structure

The fatigue crack propagation behavior of LY12 CZ aluminum alloy fastener involving center hole in 3.5%NaCl solution is investigated.The corrosion fatigue crack growth curves of the specimens at three different frequencies are presented.Experimental research shows that the corrosion fatigue crack growth rate decreases with the increasing of the loading frequencies,and in corrosive environment,the crack growth rate is larger than the rate in air.Based on the experiment results,using the AFGROW software,the numerical simulation method is carried out to analyze the corrosion fatigue crack growth behavior; and the predicted results are in good agreement with the experimental results.Finally,the residual strength analysis of the specimen using two failure modes separately is carried out,and the residual strength curve of fastener structure in corrosive environment is obtained.