Abstract: The stress-strength interference model for static strength failure is well developed, while difficulties still exist when use the concept of stress-strength interference to calculate the reliability of time-dependent failure modes such as fatigue, abrasion, corrosion, etc. There is not yet a straight forward and effective model such as stress-strength interference model even for fatigue under constant amplitude cyclic stress with uncertainty in stress amplitude. Traditional stress-strength interference model is interpreted as that to express the statistical average of the probability that strength is greater than stress, or vice versa. Thus, the same model format, which traditionally can only be used for the situation of the parameters (load and stress) of the same unit, can be applied to more general situation. In other words, the traditional model was extended to the situation of any two variables, as long as one of the variables can be expressed as a function of the other. By such a model, fatigue failure probability/reliability can be calculated with known load distribution and fatigue life distribution.

Key words: Dissimilar-dimension interference model, Fatigue, Reliability, Uncertain cyclic stress