Abstract
This paper proposes an efficient procedure for finding the possible ranges of uncertain natural frequencies of a finite element model with uncertain parameters. Uncertain model parameters are described by input fuzzy numbers and then output fuzzy numbers are calculated by fuzzy arithmetic. The fuzzy arithmetic used is based on the α-cut concept and interval analysis. To reduce computation time in the interval analysis, the global optimization technique using response surface models is introduced. Furthermore, we propose an approach for finding the feasible ranges of uncertain model parameters when the ranges of natural frequencies are specified. The examples through a simple frame model show that the membership functions of uncertain natural frequencies are efficiently and accurately estimated by the proposed procedure. In addition, the ranges of uncertain model parameters are properly evaluated by the proposed approach.
