Reliability robust design of structures under incomplete information

This paper first discusses the reliability -based design optimization (RDO) of structures under the mixture of random, interval and fuzzy variables. The sequential single-loop optimization method is applied for RDO with different combinations of uncertaities. Info-gap models are used to represent errors between "true" values and design results. A sequential algorithm for the robust reliability design is presented. Example 1 shows that the fuzzy reliability design can offer conservative result. The results of example 2 show there are different robust optimal solutions when the robustness index takes different values. When α t is greater than 0.2, the robust optimal solution does not exist. After 1291 times computation of the objective function, the optimal result can be obtained by using the sequential algorithm for the robust reliability design, while 8107 times computation are needed by the conventional optimum algorithm.