A New Cut-Set Distribution in Fuzzy Reliability Models of Mechanical Structures

Abstract

The mechanical fuzzy reliability models based on cut-set method have been applied to many fields in engineering. The reliability analysis results are affected by the cut-set distribution. In this paper, a basic mechanical fuzzy reliability model using cut-set method was established. Based on this model, the deficiency of the three previous cut-set distributions, i.e. uniform distribution, linear distribution and truncated normal distribution, was analyzed, and a new cut-set distribution named modified truncated normal distribution was proposed. The analysis results showed that when the cut-set is long enough, the reliabilities of the fuzzy models with the three previous cut-set distributions tend to a fixed value which has nothing to do with the specific mechanical structures, which makes the models have no good convergence and unreasonable. While, the fuzzy reliability model with the new cut-set distribution proposed in this paper can converge well to the classical random reliability model. Moreover, the reliabilities of a stress-strength interference problem and a resonance problem were assessed as two examples to verify the theoretical analysis results, which indicate that with this new cut-set distribution, the fuzzy reliability models have better convergence and wider applications.