Abstract:

One of the major strength problem for lap joint of aircraft is the onset and growth of cracks due to fatigue loading.At present,the analyses of the effect of structural parameters
 on lap joint life were not good enough.Life assessment models were only account for part of holistic life.Thus,fatigue properties of single bolted lap joint with different structure parameters were studied based on experiments.A predictive model of holistic life was established based on initial discontinuity state.The results show that the cracks of lap joint are not easy to find.Under certain conditions,fatigue properties of lap joint can be improved using straight hole,increasing hole space and pre-stress,decreasing hole diameter.The results show that the results produced by life assessment model of bolted joint are in close agreement with experimental ones.The simulated results may be
served as reference for damage tolerance design of the similar structures.

Key words: bolted joint, fatigue property, holistic life, initial discontinuity state

摘要：

飞机搭接件结构在疲劳载荷下会产生裂纹并扩展，而目前对搭接件结构参数与其疲劳寿命的关系研究还不够系统，且寿命估算模型只考虑了全寿命的一部分。对不同结构参数的三螺栓单搭接件的疲劳特性进行了试验研究，并以现有工程方法为基础，构建了基于材料初始不连续状态的搭接件全寿命估算模型。结果表明，搭接件的疲劳破坏具有一定的隐蔽性，在一定条件下，采用直孔形式、增大孔间距和螺栓预紧力、减小孔直径等都可以改善搭接件的疲劳特性。数值估算结果与试验结果的对比表明，所建寿命模型具有一定的精度，能满足工程需要，计算结果和结论可作为该类结构损伤容限设计的参考依据。

关键词: 螺栓连接件, 疲劳特性, 全寿命, 初始不连续状态