随机载荷作用下构件疲劳可靠性分析方法

A METHOD FOR THE FATIGUE RELIABILITY ANALYSIS OF MACHINE PARTS UNDER RANDOM LOADS

本文建立了用于随机载荷作用下构件疲劳可靠性分析的二维应力强度干涉模型。当影响疲劳强度的诸因素为随机变量时,给出了在二维应力强度干涉模型中考虑这些因素的方法,并用蒙特卡罗(Monte Carlo)方法求解了该模型。最后将上述模型应用于工程实际。

One-dimensional model of stress-strength interference was often used in the fatigue reliability analysis in the past. In fact, it is necessary to describe the fatigue loads with two parameters, such as load amplitude and mean load;and they should he considered as the two random variables. The two-dimensional model of stress-strength interference is set up in this paper, and it can be applied to the fatigue reliability analysis of the machine parts under random loads. If the factors of effect on fatigue strength are considered as random variables, the method of taking account of them in the two-dimensional model of stress-strength interference is suggested. The two-dimensional model of stress-strength interference is calculated by the Monto-Carlo method, and it is used in engineering. It is proved that the two-dimensional model of stress-strength interference is more reasonable than the traditional one dimensional model, because it takes account of the effects of the amplitude value and mean value of fatigue load at the same time. When the model is calculated by the Monte-Carlo method, the applied stress on a machine part, fatigue strength of material and the factors influencing the fatigue strength are allowed to be the random variables of any known distribution.