基于修正的局部应力应变法估算连接件疲劳寿命  

Prediction of Fastenings Fatigue Life Based on Modified Local Stress-Strain Method

作　　者：祝青钰[1] 隋明丽[2] 韩峰[1] 张辉[2] 

机构地区：[1]北京理工大学爆炸科学与技术国家重点实验室,北京100081 [2]中国航空综合技术研究所,北京100028

出　　处：《力学季刊》2013年第3期480-486,共7页Chinese Quarterly of Mechanics

摘　　要：飞机机体结构疲劳裂纹的萌生与扩展几乎都发生在紧固件连接处,预测结构连接件的疲劳寿命具有重要意义。为了准确计算连接件疲劳寿命,提出了一种修正的局部应力应变法,该方法首先采用应力严重系数法和修正Neuber法分析连接件高应力区的应力、应变,然后利用Manson-Coffin方程计算疲劳寿命,此外考虑到在中、高周疲劳里表面加工和尺寸因素的影响是不能忽略的,对应变-寿命曲线的弹性段作了修正以使其同时适用于高、低周疲劳寿命的估算。以搭接件为算例进行疲劳寿命计算,并使用MTS Landmark试验机对搭接件进行疲劳试验。结果表明,采用此方法估算的连接件疲劳寿命与试验结果相比误差小于16%,证明了此方法的有效性。Airframe structural fatigue crack initiation and propagation almost occurred at the fasteners, therefore, it is significant to predict fatigue life of fastenings. The modified local stress-strain method is brought up for calculating accurately the fastenings fatigue life. The stress and strain of high-stress areas of fastenings by the stress severity factor method and the modified Neuber method were analyzed by this method, then the fastenings fatigue life was calculated with the Manson-Coffin equation. In addition, this method can be not ignored to taking into account the impact of surface processing and size factor in high- cycle fatigue, the elastic segment of strain-life curve has been amended so that it applies to both high and low cycle fatigue life prediction. The fatigue life of fastenings was tested with MTS Landmark test ma- chine and the fastenings fatigue life was calculated with the modified local stress-strain method. The re- sults showed that the relative error is less than 16%, this prove that the modified local stress-strain method is effective.

关 键 词：连接件 应力严重系数 局部应力应变法 应变-寿命曲线 高周疲劳 

分 类 号：V215.5[航空宇航科学与技术—航空宇航推进理论与工程]