2A12航空铝合金多轴疲劳试验及应力准则寿命预测模型研究

摘要

Based on multiaxial fatigue failures,compound fatigue tests of stress-amplitude ratio, tension-torsion phase and average stress variables were carried out on 2A12 aluminum alloy.With the discussions of 3 common multiaxial fatigue life predictive models of stress criterion which included Lee criterion,Carpinteri criterion and Sines criterion,a modified model was built on the basis of Carpin-teri criterion considering effects of both stress-amplitude ratio and tension-torsion phase.The compar-ison between predicted life and experimental life under different conditions shows that Lee criterion's predictive results are too over-estimated for the above experiments.Without consideration of stress-amplitude ratio and tension-torsion phase,the predicted life of Carpinteri criterion and Sines criterion have large errors compared with the experimental life.The new modified stress criterion life predictive model may give results that 90 percent of life prediction data will be in the 2 times error band with dif-ferent conditions.%针对多轴疲劳失效问题,选取2A12航空铝合金进行应力幅比变量、相位差变量和平均应力变量的多轴疲劳试验.对常用的3种多轴疲劳应力准则寿命预测模型(即Lee准则、Carpinteri准则和Sines准则)进行讨论,并通过引入应力幅比参量和相位差参量,提出基于Carpinteri准则的修正模型.将不同条件下2A12航空铝合金的试验寿命与不同应力准则下模型的预测寿命进行比较,结果表明:Lee准则对上述多轴疲劳试验的预测结果过于危险;Carpinteri准则和Sines准则由于未考虑拉扭应力幅比和相位差因素,预测寿命与实际寿命相比均出现了较大偏差;修正后的应力准则寿命预测模型在不同条件下90%的寿命预测数据在两倍误差带内.