多轴随机振动疲劳频域方法的研究

Research on Frequency Domain Method for Multiaxial Random Fatigue

传统的多轴疲劳时域分析法需要得到结构件整个随机加载历程,这种方法非常耗时,效率很低。针对这种情况,提出一种基于临界面上最大正应力和剪应力准则的频域分析方法。以悬臂梁作为疲劳强度评定算例,比较了基于Von Mises等效应力法的多轴疲劳时域法与提出的频域法的分析结果。研究结果表明,根据2种方法计算出悬臂梁4个工况疲劳寿命的相对误差在5%之内,而且使用频域分析法计算时间少,效率更高。

The tradifional time domain analysis method for multi-axis fatigue needs the whole stochastic loading process of the component.It is very time-consuming and inefficient.In this case,an frequency domain analysis method based on the maximum normal stress and shear stress criterion on the critical surface is proposed.This paper evaluates the fatigue strength of cantilever beam,for example.The result obtained by the time domain analysis method for multi-axis fatigue based on Von Mises equivalent stress is compared with one obtained by the frequency domain analysis method.The result shows that the relafive error of the fatigue life of the cantilever beam is within 5%,however,the efficiency of using the frequency domain analysis method is higher.