Abstract:

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.

Key words: fatigue, reliability, model of stress-strength interference, the MonteCarlo method