AA7075-T6 Ⅰ-Ⅱ复合疲劳裂纹扩展研究  

Experimental Study on Ⅰ-Ⅱ Mixed-mode Fatigue Crack Growth of AA7075-T6

作　　者：吴鹏飞 杨邦成[1] 岳仕航 WU Pengfei;YANG Bangcheng;YUE Shihang(School of Civil Engineering,Kunming University of Science and Technology,Kunming 650504)

机构地区：[1]昆明理工大学建筑工程学院,昆明650504

出　　处：《宇航材料工艺》2022年第1期82-88,共7页Aerospace Materials & Technology

摘　　要：通过AA7075-T6铝合金在不同加载角度下的Ⅰ-Ⅱ复合高周疲劳裂纹扩展试验,利用FRANC3D中M-积分计算了复合型裂纹尖端的等效应力强度因子幅值,结合七点递增多项式对数据处理,得出了复合疲劳裂纹扩展速率曲线,分析了复合疲劳性能,并探讨了复合裂纹扩展的路径及断口特性。结果给出了纯Ⅰ型疲劳裂纹扩展速率曲线在稳定扩展阶段的Paris公式的参数;并表明:Ⅰ型疲劳裂纹扩展寿命最长,复合疲劳裂纹扩展寿命都有不同程度的减少;复合疲劳裂纹开裂方向的数值分析及实验结果与理论吻合;复合疲劳断口表现为脆性断裂。Based on the Ⅰ-Ⅱ mix-mode high cycle fatigue crack propagation tests of AA7075-T6 aluminum alloy under different loading angles,the equivalent stress intensity factor(SIF)amplitude of the mix-mode crack tips was calculated by using M-integral in FRANC3 D. By processing the data with seven-point increasing polynomial,the growth rate curve of mix-mode crack tip was calculated. The mix-mode fatigue properties were analyzed and the path and fracture properties of mix-mode crack propagation were discussed. The result of the experiment shows the parameters of Paris formula of pure type Ⅰ fatigue crack propagation rate curve in the stage of stable growth and proves that,the lifespan of the type Ⅰ fatigue crack propagation is the longest,and the life of mixmode fatigue crack propagation have suffered various degrees of reduction. The numerical analysis and experimental results of the cracking direction of the mix-mode fatigue crack are compatible with the theory,and the fracture of the mix-mode fatigue is characterized by brittle fracture.

关 键 词：复合型裂纹 裂纹扩展速率 应力强度因子 开裂角 宏观断口 

分 类 号：V255.1[一般工业技术—材料科学与工程]