Fuzzy lectotype of deep water jacket platform based on fatigue reliability optimization design

The complicated system decision problem for design scheme optimization of deep water jacket platform was analyzed. The four initial design schemes with different structure types were proposed. The optimal structure design parameters for each scheme were obtained by optimum design method, in which the nominal fatigue reliability index of structure system obtained by spectral method was taken as a key constraint condition. According to the optimized structural performance parameters, the factors which had effects on the type selection of deep water jacket platform were comprehensively considered. The objective weight and relative membership degree for each factor were obtained by binary comparison method. Finally, the three-level fuzzy optimum decision method was used for the fuzzy optimization. A deep water jacket platform for 200 m was taken as an example. The results show that the optimal performance parameters obtained by optimization analysis of initial design schemes can give accurate quantitative indexes and the fuzzy factors are reduced compared with the conventional methods. The method is more beneficial to obtain the reasonable evaluation of deep water jacket platform.