含高频的载荷下飞机薄壁结构振动疲劳寿命分析

摘要

Aircraft structure is often in the dynamic loading environments due to sudden wind,maneuver,and so on,that may lead to fatigue failure and serious accidents.Based on the Dirlik fatigue life prediction method,combining with structural damage calculation and modal analysis,this study investigates the mechanisms of vibration fatigue failure by taking a typical thin-walled structure when it is in a special load environment which can provoke the fundamental frequency mode and a higher order mode.It is shown that the sharp reduction in fatigue life is due to the combination of the resonance mode together with high modes with some special characteristics.%飞机结构在使用过程中常常会由于突风等振动载荷的原因发生疲劳破坏导致严重的事故。基于Dirlik疲劳寿命估算方法,通过对薄壁结构施加不同的载荷谱,结合结构的损伤计算和模态分析,研究了当飞机典型薄壁结构处于某种特殊的载荷环境中,可以同时激起其基频模态和某一高阶模态时,其振动疲劳寿命相对于只有基频共振时急剧下降的原因,并分析了这种高阶模态的特征。