周期性疲劳载荷作用下的应力-强度干涉模型

Stress-Strength Interference Model under Circular Fatigue Loads

为了评估周期性疲劳载荷作用下的结构可靠度,设结构初始强度为服从任意分布的随机变量,推导出周期性疲劳载荷作用下的结构剩余强度表达式。利用通用生成函数法对结构剩余强度和疲劳载荷构成函数的概率特征进行计算,从而建立了周期性疲劳载荷作用下的应力-强度干涉模型。利用45#钢疲劳试验数据对提出模型的有效性进行验证和分析。结果表明,该模型能够有效地评估周期性疲劳载荷作用下的结构可靠度。

The conventional stress-strength interference （SSI） model is a basic model for reliability analysis of mechanical components. In this model, the component reliability is defined as the probability of the strength random variable larger than the stress random variable. But for a component under circular fatigue loads conditions, its reliability can not be calculated directly by using the SSI model. To evaluate the structural reliability under circular fatigue loads, an expression of residual strength under circular fatigue loads is derived firstly in the assumption that the initial strength is a random variable which follows any distribution. Then, a stress-strength interference model under circular fatigue loads is proposed by employing the universal generating function to calculate the probability characteristics of a function constituted by residual strength and fatigue loads. Finally, the fatigue experimental data of 45^# steel is used to testify and analyze the proposed model. The results indicate that the proposed model can be used to evaluate the structural reliability under circular fatigue loads.