铝合金切口件在四组变幅载荷下3.5%NaCl溶液中腐蚀疲劳裂纹起始寿命试验研究与估算模型

EXPERIMENTAL INVESTIGATIONS AND PREDICTION OF CORROSION FATIGUE CRACK INITIATION LIFE OF NOTCHED ALUMINUM ALLOY SPECIMENS IN 3. 5 % NaCl SOLUTION UNDER FOUR VARIABLE AMPLITUDE LOADING

试验研究了铝合金切口件在4组变幅块谱下、3．5％NaCl溶液中腐蚀疲劳裂纹起始寿命．结果表明，变幅载荷谱中的大超载会显著延长腐蚀疲劳裂纹起始寿命，并且加载顺序具有明显的影响．根据反映大小载荷交互作用的超载腐蚀疲劳裂纹起始寿命曲线和Miner累积损伤定则，建立了变幅载荷下切口件腐蚀疲劳裂纹起始寿命估算模型，应用该模型估算的结果与试验结果相吻合．

Corrosion fatigue crack initiation lives of aluminum alloy notched soecimens in 3. 5 % NaCl solution under four kinds of variable amplitude loading block spectra were investigated experimentally. The results show that overloading in the spectrum prolongs corrosion fatigue crack initiation life considerably, and the loading sequence has a significant effect. So, the overloading effect must be considered in the prediction of corrosion fatigue crack initiation life under variable amplitue loading. According to the corrosion fatigue crack initiation life curves that reveal the effect of overloading and Miner's accumulative damage rule, a medel for predicting corrosion fatigue crack inihation life under variable amplitude loading has been established. ffen, the model was used to predict the corrosion fatigue crack initiation life under the selected spectra. The predicting results show a good agreement with that of experiment.