Abstract: The ordinary failure criterion of wear is explained. A clear explanation of the representativeness of ultimate wear quantity is given. The safety margin equation for wear reliability is presented. It is assumed that both the practical wear quantity and the ultimate wear quantity are random variables, they follow normal distribution, and there is no correlation between them. The typical curves of wear quantity corresponding to the time are shown. The method of computing wear reliability is given. The basic concepts and the procedure of this computational method are explained by an illustrative example. The reasonable design criteria for preventing adhesive wear seizure are presented.

Key words: wear reliability, ultimate wear quantity, reliability safety margin equation