相位角加载条件下2A12铝合金多轴疲劳失效行为

发布时间：2018-09-05 15:47

【摘要】：采用SDN100/1000电液伺服拉扭复合疲劳试验机对2A12铝合金进行不同相位角加载条件下多轴疲劳试验研究,通过加载循环曲线和微观断口形貌分析失效机理,对不同损伤累积模型的预测效果进行评价,修正Manson损伤曲线模型以期达到更好的预测效果。结果表明:单级加载条件下,随相位角正弦值的增加疲劳寿命线性递减,当相位角为0°时,轴向硬化、软化交替出现,切向出现循环硬化,90°加载下轴向和切向单独作用效果明显;两级累积路径下,随一级加载周次的增加多轴疲劳寿命延长,0°加载阶段轴向和切向都出现循环硬化现象,两种路径下断口都呈现出多裂纹源特征,在裂纹源区附近观察到台阶状形貌,扩展区存在大量划痕和鳞片状花样;修正后的Manson损伤曲线模型预测误差均在15%以内。
[Abstract]:The multiaxial fatigue test of 2A12 aluminum alloy under different phase angle loading conditions was carried out by using SDN100/1000 electro-hydraulic servo tension and torsion compound fatigue testing machine. The failure mechanism was analyzed by loading cycle curve and micro-fracture morphology. The prediction effect of different damage accumulation models was evaluated and the damage curve model of Manson was revised to achieve better prediction effect. The results show that the fatigue life decreases linearly with the increase of sinusoidal value of phase angle under single stage loading. When the phase angle is 0 掳, axial hardening and softening occur alternately. Under tangential cyclic hardening (90 掳) loading, the axial and tangential effects are obvious, and under the two-stage cumulative path, both axial and tangential cyclic hardening occurs with the increase of multiaxial fatigue life at 0 掳loading stage with the increase of the first-order loading cycle. The fracture surface of the two paths shows the characteristics of multiple crack sources, the step shape is observed near the crack source, a large number of scratches and scale-like patterns exist in the spreading region, and the prediction error of the modified Manson damage curve model is less than 15%.
【作者单位】：中国民航大学中欧航空工程师学院;
【基金】：国家自然科学基金(11502285) 中央高校基本科研业务费中国民航大学专项(3122017112)
【分类号】：O346.2

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