Fatigue lifetime assessment based on probabilistic and non-probabilistic mixed model

Seeing that stochastic variables and non-probabilistic variables coexist in engineering structures in many encountered cases, a hybrid probabilistic and non-probabilistic model for fatigue lifetime estimation is proposed. The probability distribution function of the lower bound of the fatigue lifetime is fitted through two steps of analysis. The estimated value of the lower bound of the fatigue lifetime can be obtained when the confidence level is given. An example illustrated the application of the proposed theory. The results of the proposed model were compared with that of interval analysis model. It was shown that the results have compatibility with the meanings of probability theory and interval analysis and the model has reasonableness and feasibility.