The Fuzzy Reliability Optimum Design of Offshore Jacket Platforms

In consideration of the fuzzy constraint boundary and through analysis of structural reliability, a model of structural fuzzy optimum design is established based on reliability for offshore jacket platforms. According to the characteristics of offshore jacket platforms, the tolerance coefficient of the constraint boundary is determined with the fuzzy optimization method. The optimum level cut set λ^*, which is the intersection of the fuzzy constraint set and fuzzy objective set, is determined with the bound search method, and then the fuzzy optimum solution of fuzzy optimization problem is obtained. The center offshore platform SZ36-1 is designed with the fuzzy optimum model based on reliability above; the results are compared with those from deterministic optimum design and fuzzy optimum design. The tendency of design variables and its reasons in the above three methods are analyzed. The results of an example show that the fuzzy optimum design based on reliability is stable and reliable.