Analysis Method Of Fuzzy-Random Reliability And Sensitivity For Structures

In the reliability analysis of engineering structures, uncertain variables are usually considered as purely fuzzy or purely random ones. However, in practice, the variables of structures involving both fuzzy and random variables. For this problem, this thesis paper has done the following work on the basis of present research.The applications of the existing unified models for fuzzy-random reliability are extended. A cantilever is taken as an example, verifying that the unified model is applicable not only in the linear reliability models but also in the nonlinear ones. Based on the unified model for fuzzy-random reliability, the expression of a general numerical simulation analysis method is derived for fuzzy-random reliability and its sensitivity. A middle-position methods, an efficient and more precise equivalent normalized conversion method, is proposed for the problem that membership function of fuzzy data does not obey normal distribution in the fuzzy-random models. Through three classical examples of reliability analysis of engineering structures, the results obtained from the three methods, numerical simulation,3σ method and middle position method, are compared, proving that the middle-position method is quite practical and efficient under the demand of low calculation accuracy.