铆钉连接件细节应力分析及疲劳裂纹形成寿命预估

 首先建立简化的力学模型模拟复杂的铆钉连接件结构，并用有限元软件对所建立的模型进行细节应力分析。然后利用损伤力学守恒积分原理得到计及损伤耦合效应的集中应力表达式。在此基础上，根据由热力学原理导出的以损伤驱动力表示的损伤演化方程，给出裂纹形成寿命与载荷关系的解析表达式。进一步，按照某种材料的部分标准试件的中值疲劳曲线拟合损伤演化方程中的材质参量，并利用同类材料的其他标准试件的中值疲劳曲线进行寿命预估方法验证。最后，给出了国产某型客机危险部位具有不同存活率的疲劳裂纹形成寿命。

Detail Stress Analysis and Fatigue Crack Initiation Life Prediction of Riveted Joint

A simplified mechanical model is established to simulate the complicated rivet joint structure and finite element software is applied to the detail analysis of above model.Then the principle of conservative integral of damage mechanics is utilized to obtain the concentrated stress expressions with damage coupling effect.On the base of above expressions,the analytical relation between the crack initiation life and the concentrated stress without damage coupling effect is built by the damage evolution equation which is set up on the basis of the thermodynamics laws and expressed as a function of damage driving force.Further more,according to the median fatigue curves of some standard specimens made of certain material,the material parameters in the damage evolution equation is fitted and the life prediction method is verified by the median fatigue curves of other standard specimens for the same material.At last,the crack initiation lives with different serviceable probabilities are predicted for the critical parts of certain civil aircraft fuselage.