比例加载下应力幅比对2A12T4疲劳寿命的影响.pdf

2010 8 August 2010 36 8 Journal of Beijing Univers ity of Aeronautics and Astronautics Vo.l 36 No8 2A 12T4 时新红 张建宇 鲍 蕊 费斌军 ( , 1001 1) : 采用 2A 12T4铝合金漏斗形试件, 针对不同拉扭应力幅比, 行了比例加载 下多轴高周疲劳寿命试验, 研究了不同应力幅比对多轴高周疲劳寿命的影响. 针对试验结果, 采用 3种常用的多轴高周疲劳寿命预测模型, 包括等效应力准则应力不变量准则临界面准 则 行了预测. 结果表明: 在相同的VonM ises等效应力下, 随着扭转应力幅与拉压应力幅比 值的增大, 疲劳寿命逐渐升高. 等效应力准则的预测结果或过于危险, 或过于安全; 应力不变量 准则的预测结果认为应力幅比的变化对疲劳失效没有影响, 与试验结果不符; 临界面准则的预 测结果优于其他准则. : 疲劳; 多轴高周疲劳; 疲劳寿命; 比例加载; 应力幅 : O 346. 2 : A : 10015 65( 2010) 080 6504 E ffect o f stress am p litude on h ighcyc le fatigue life of 2A 12T4 a lum inum a lloy unde r p ropo rtiona l load ing Shi X inhong Zhang Jianyu Bao Ru i FeiBinjun ( School of Aeronautic Science and Engineering, Beijing University ofA eronautics andA stronautics, Beijing 1001 1, China) Abstract: Fatigue life expermi entsw ith funneledshape specmi ensw ere conducted to investigate the effect of stress amplitude on mu ltiaxial h ighcycle fatigue failure of 2A 12T4 alum inum alloy under tensiontorsion proportional load ing. Based on the expermi ent results, three kinds of lifeprediction criteria, w hich w ere w ide ly used formultiaxial highcycle fatigue analysis, w ere d iscussed. The resu lts show e that under the same von M ises equ ivalent stress, fatigue life raised gradually when the ratio of stress amp litude in tension and torsion increased. Fatigue life of un iaxial tension is the shortest and that of pure torsion is the longes.t The forecast re su lts of equivalent stress criteria are either too dangerous, or too conservative. Stress invariant criteria cannot predict the mi pact of stressamp litude ratio on mu ltiaxial highcycle fatigue failure. Criticalplane criteria has better predict