随机载荷循环作用下的机械结构疲劳寿命预测模型

摘要

Based on the nominal stress method for fatigue life prediction, a predicting model for the fatigue life of mechanical structures under random cyclic loads was developed herein. The uncertainty of the cyclic loads applied on the mechanical structures was analyzed. With the number of load application as the life index, the fatigue life prediction models of mechanical structures under random cyclic loads were developed with the probability weighted method and the Miner linear cumulated damage rule, when the relationships between fatigue life and stress can be expressed as the exponential function and the power function, respectively. Finally, the models proposed were used to predict the fatigue life of a rotating shaft.%基于名义应力法建立了随机载荷循环作用下的结构疲劳寿命预测模型。分析了结构所受循环载荷作用的不确定性特征,在以循环载荷作用次数为寿命度量指标框架下,运用概率加权法和线性Miner累积损伤法则,分别建立了疲劳寿命与应力之间关系分别服从指数函数和幂函数两种形式时,随机载荷循环作用下的结构疲劳寿命预测模型,并运用所建立的模型对某转动轴的疲劳寿命进行了预测研究。