Based On The Method Of Moments Reliability And Reliability Sensitivity Study

Based on the advantages, such as wide applicability, easy implementation and high efficiency etc., of the moment method, the moment method is employed to establish a series of novel moment methods for random Reliability Sensitivity (RS), fuzzy failure probability, fuzzy RS and RS with correlative variables. The major contributions are listed as follows:1. By use of point estimation of the first four order moments of performance function and moment based random failure probability method, a new RS method is presented. The partial differentials of the moment of the performance function to distribution parameters of basic variables are derived. Furthermore, the relationship between the failure probability and the moment of the performance function is employed to derive the partial differentials of the failure probability to the distribution parameters of the basic variables. Hereby, the RS is obtained. The presented method is suitable for the implicit limit state equation and applicable to non-normal random variables.2. On the basis of approximate algorithm for expectation, a general RS algorithm is presented. According to the integral formulation between the moment of the performance function and the joint probability density function of the basic random variables, the partial differentials of the moment of the performance function with respect to the distribution parameters of the basic random variables are derived, and each partial differential is transformed as an expectation. Then the RS is approximately transformed as the expectation. The significant advantages of the presented general RS method include independence of analytical expression of the performance function, applicability to non-normal random variable and to multiple failure modes.3. For fuzzy reliability analysis with fuzzy failure state and fuzzy safety state, a moment method is proposed to calculate fuzzy failure probability. In the integral operation of the fuzzy failure probability, the integral region is scattered according to the value of performance function. Then the calculation of the fuzzy failure probability can be transformed into that of the random failure probability, and the moment method is employed to obtain the fuzzy failure probability directly. The proposed method possesses high precision for the low and the medium dimensionality...