基于损伤力学的含预腐蚀损伤铝合金的疲劳寿命预测

在工程结构中，腐蚀疲劳破坏是一种常见的现象，腐蚀坑处往往形成疲劳源，严重影响材料的疲劳特性。基于连续损伤力学理论，提出了含预腐蚀损伤铝合金疲劳寿命预测方法。首先，将腐蚀的影响分为2个方面，即腐蚀造成局部初始损伤和腐蚀形成的蚀坑造成局部应力集中；其次，建立了考虑预腐蚀损伤的疲劳损伤演化方程，并实现了相应的数值解法；然后，根据预腐蚀疲劳试验结果与数值计算结果，得到预腐蚀引起的材料初始损伤；最后，采用数值解法，对含预腐蚀坑的铝合金进行了寿命预估，并与试验结果进行对比，验证了所提方法的有效性。 

Fatigue life prediction of aluminum alloy with pre-corrosion damage based on damage mechanics

In engineering structures, the corrosion fatigue failure is a common phenomenon. The fatigue crack often occurs around the corrosion pit, which seriously affects the fatigue characteristics of materials. In this paper, based on the continuous damage mechanics, a method is proposed for the fatigue life prediction of aluminum alloy with pre-corrosion damage. First, the influence of corrosion is studied from two aspects: one is the local initial damage caused by corrosion, and the other one is the local stress concentration caused by corrosion pit. Then, the fatigue damage evolution equations considering pre-corrosion damage are established and the related numerical solution is implemented. After that, according to the results of pre-corrosion fatigue test and numerical prediction, the initial damage of material caused by pre-corrosion is obtained. Finally, the fatigue life of the aluminum alloy with pre-corrosion pit is predicted by the proposed method, and the predicted results are compared with the experimental results, which verifies the effectiveness of the proposed method.