铝合金薄板结构多模态随机振动疲劳分析

Vibration fatigue analysis of thin aluminum alloy plate under multi-modal random vibration loadings

基于数值方法分析了铝合金薄板在共振和非共振状态下的动态响应,结合Dirlik疲劳寿命估算方法,确定振动应力是影响结构振动疲劳寿命的主要因素.利用数字图像相关技术,通过随机振动试验验证了数值计算动应力的准确性,研究了结构在多模态随机载荷激励下的振动特性,发现高阶模态载荷会影响结构振动疲劳损伤,引起结构振动疲劳寿命的急剧降低,并分析了产生这一现象的原因.

Based on Dirlik fatigue life prediction method , dynamic response and fatigue life of thin aluminum alloy plate under resonant or non-resonant state were calculated by numeri-cal method.It was shown that dynamic stress was a major factor affecting the vibration fa-tigue life of structure .Digital image correlation （ DIC） was introduced and random vibration tests were performed to verify the accuracy of numerical calculation of dynamic stress .Vibra-tion properties of the specimen under multi-modal random loadings were studied , and the re-sults showed that higher modal loadings affected the vibration fatigue damage and caused drastically reduction in vibration fatigue life .