小钉密排代替大钉疏排的铆接接头疲劳寿命预估与优选设计

Fatigue Life Prediction and Structure Optimization of the Rivet Joints by Denser Spacing of Smaller Rivets Instead of Sparser Spacing of Bigger Rivets

连接件钉排布决定了钉载分布,进而决定了连接件的疲劳寿命。优化连接件钉排布,将有效地提高连接件疲劳寿命。损伤力学将结构应力和材料损伤分析结合起来,较为准确地描述应力—损伤的耦合作用以及损伤演化,为工程结构疲劳分析提供有力的依据。以损伤力学为理论基础,以小钉密排代替大钉疏排为连接件钉排布设计原则,结合有限元计算,对连接件钉排布进行优化设计,并预估连接件疲劳寿命。结果表明,小钉密排代替大钉疏排不仅可以有效降低连接件应力水平,显著提高其疲劳寿命,同时也有利于减小连接件质量,实现连接件延寿和减重的双重优化。另一方面,运用损伤力学理论方法结合有限元计算,进行结构疲劳寿命预估,大大减少了试验工作量,为结构抗疲劳设计提供理论指导,大大缩短了连接件结构设计周期,还可用于实际工程结构疲劳损伤的实时监测。

Rivet arrangements of joints determine the distributions of rivet loads,and then the fatigue lives of joints.Optimization of rivet arrangements of joints will efficiently elongate the fatigue lives of joints.Damage mechanics properly describes the coupling effects of stresses and damage and evolution of damage,by combining stress analysis of structures with damage analysis of materials.This methodology provides a powerful tool of fatigue analysis for engineering structures.Based on the theoretical method of damage mechanics,optimization of rivet arrangements of joints is discussed,under the guideline of ＂denser spacing of smaller rivets instead of sparser spacing of bigger rivets＂（DSSB）,and the fatigue lives of the resulting joints are evaluated in aid of finite element code.Those selected designs possess multiple outstanding advantages of stress level reduction,fatigue life extension,and weight minimization of joints comprehensively.Additionally,the damage mechanics method provides the theoretical instruction for joint design against fatigue,with limited experiments within much shorter design period,which can also be adopted as real-time monitor of structure damage evolution.