Abstract:

The quantitative techniques of corrosion pits of 2 series pre-corrosive  aerial  aluminum alloys  were investigated.In  the pre-corrosive conditions,it is found that the fatigue crack starts at the bottom of its corrosion pit to result in a radial propagation and a decrease of the crack initiation life.Thus,a  new  quantitative  method  of corrosion  pits  was  pointed  out  by  ignoring the stages  of the crack nucleation.According to the equivalence principles  of the area,the corrosion pit was equivalent to a semi-elliptical surface crack in order  to  directly predict the fatigue life of aluminum alloys.Based on the NASGRO software,the validation of proposed quantitative techniques of corrosion  pits  and fatigue life prediction methods  was  performed and the research results enable the possibility of the fatigue life evaluation of complicated structures.

Key words: pre-corrosion;corrosion pit;quantitative , technique;fatigue , life prediction

摘要：

针对2系列预腐蚀损伤航空铝合金材料进行腐蚀坑当量化技术研究,结果表明,在预腐蚀条件下，疲劳裂纹起始于腐蚀坑底部并呈辐射状向内扩展，降低了材料裂纹萌生寿命。因此，忽略裂纹成核阶段，提出了一种根据面积等效原理将腐蚀坑当量化成半椭圆表面裂纹的当量化处理方法，直接计算材料的疲劳寿命，并利用NASGRO软件验证了腐蚀坑当量化以及基于断裂力学预测材料疲劳全寿命方法的可行性。研究结果为复杂结构件的寿命评估提供了依据。

关键词: 预腐蚀, 腐蚀坑, 当量化技术, 疲劳寿命预测