A topology optimization methodology for the offshore wind turbine jacket structure in the concept phase

Abstract

This paper proposes a topology optimization methodology for offshore wind turbine (OWT) jacket structure design in the concept phase. First of all, modal analysis and load calculation of a 5 MW reference OWT are performed. On the basis of finite element analysis, the displacement and von Mises stress of multi-jacket support structures in various ultimate loading conditions are explored. Furthermore, structural topology optimization formulation aims to minimize a weighted normalized objective for the OWT jacket structure. Therefore, several optimum structures are obtained by adjusting weighting coefficients. For the coupling effect between the structure and applied load, load recalculation, displacement, and stress reanalysis are performed on the jacket structure based on the topological configuration under a specific weighting factor. Comparisons are made between the reference structure and optimized structure. Without the addition mass, the fundamental natural frequency of the optimized structure is marginally increased, but the maximum displacement and von Mises stress are drastically lowered, indicating that the optimized structure outperforms its reference counterpart. These findings conclusively demonstrate that the proposed TO technique for the design of OWT jacket structures is feasible and preferable.