飞机谱载下铝合金锪窝孔结构腐蚀疲劳研究  

CORROSIVE FATIGUE OF STRUCTURES WITH DIMPLE HOLES UNDER SPECTRUM LOADING

作　　者：沈海军[1] 郭万林[1] 吕国志[2] 

机构地区：[1]南京航空航天大学航空宇航学院,333信箱南京210016 [2]西北工业大学飞机系,西安710072

出　　处：《力学学报》2003年第1期21-25,共5页Chinese Journal of Theoretical and Applied Mechanics

摘　　要：通过战斗机谱载下7475-T761铝合金紧固孔试件空气与3.5％NaCl环境中的疲劳试验和断口分析,得到了相应结构疲劳全寿命和孔边角裂纹的裂纹长度-寿命数据.通过三维有限元分析得到了孔边角裂纹的应力强度因子.采用我们新近发展的三维疲劳寿命分析软件,基于材料裂纹扩展基准曲线和一组直通孔实验数据,对锪窝孔结构角裂纹的疲劳和腐蚀疲劳扩展寿命进行了预测.结果表明,提出的基于三维断裂力学的寿命预测方法和软件对复杂结构的全寿命有精确的预测能力,比传统的局部应变法优越,可适用于复杂环境下三维结构的疲劳寿命分析.Experimental investigation and life prediction are made for structures with straight holes and dimple holes in both laboratory ambient and 3.5 % NaCl solution under spectrum Loading. With the aid of acoustic emission, label loading and fractography technique the crack growth data are obtained in both environments. Stress intensity factors for the corner crack emanated from the dimple hole are evaluated by three-dimensional(3D) finite element method. Life prediction of the tested structures is made by use of the modified FASTRAN-Ⅱ code on the basis of corresponding fatigue crack growth rate curves. It is shown that once the initial defect size a0 is determined by one set of test data, it can be used together with the 3D crack growth method to provide accurate life prediction in alternative structure and loading condition. Life prediction by the traditional local strain method is also made which is shown to be less reliable than the 3D crack growth method.

关 键 词：钩窝铆接 飞机 谱载 铝合金锪窝孔结构 腐蚀疲劳试验 疲劳寿命预测 三维有限元方法 

分 类 号：V215.51[航空宇航科学与技术—航空宇航推进理论与工程]