Abstract: As for the problem of life prediction of mechanical components, the essential factors affecting the life and its probabilistic characteristics is taken in account and the failure behavior of components is described with the stress-strength interference method. Then, the method for determining the probability distribution of life of components with time as life parameter is studied, and the cumulative distribution function, the probability density function and mean life function of components, which can embody the effect of parameters including stress, strength and its degradation, are developed. The rules that the life probabilistic characteristics of components change as the parameters of stress and strength, are studied. With the method and model proposed, according to the structural parameters and operating profile of components, the life probability distribution characteristic can be determined in the development stage, and the process of design, test, operation and maintenance of components can be directed more scientifically.

Key words: mechanical components;failure behavior;life prediction;probability distribution;mean life