Study on robust structures (4th report, design method and discussions on fuzzy-robust structures)

In this paper, a new design method of robust structures using fuzzy sets is proposed. Robust structures have characteristics that are only slightly modified by any changes in external forces, boundary conditions, and productive errors. In our previous studies, the design method of robust structures using sensitivities were mainly investigated. However, sensitivities provide only local information when their values are evaluated. Therefore, it is not clear whether structures designed by sensitivities have robustness widely or not. This paper shows a design method of a structure that holds robustness widely. Because this method uses fuzzy sets, robust structures-designed with this method are called fuzzy-robust structures. In the numerical examples, fuzzy-robust structures were designed. Then the effect of a change in the membership function or the α-level was examined. The effectiveness of this method is also discussed.