Reliability analysis method considering random, interval and fuzzy parameter uncertainties compounded by ontological ambiguity

A reliability analysis method considering hybrid random, interval and fuzzy parameter uncertainties compounded by ontological ambiguity is proposed in this paper. Firstly using the interval ranking strategy, the interval failure possibility index is employed to capture the safety characteristic from the interval uncertainty. Secondly using a mathematical equivalent transformation, a generalized interval failure possibility index is developed to quantify the effect of both interval uncertainty and ontological ambiguity on the safety degree. Finally the eventual generalized failure possibility index is calculated by an integral operation where all three parameter uncertainties and ontological ambiguity are considered simultaneously. A three-layer nested loop simulation method (TLSM) is primarily proposed to estimate the generalized failure possibility index, which is accurate but time-consuming. In order to improve the computational efficiency, a single-layer loop simulation method (SLSM) is presented by employing an equivalent transformation of the integral. Test examples illustrate the feasible and rationality of the proposed failure possibility index and demonstrate the accuracy and efficiency of the two proposed computational methods. The calculation results indicate that compared with the TLSM, the SLSM can reduce the computational cost dramatically with acceptable precision.