Two-level Layout Optimum Design Method For Stiffened Curved Panel

Weight is an important performance index in aerospace field. Weight reduction is an permanent topic for aircraft structure designer, it can not only improve endurance and mobility capability of aircraft, but also save fuel. Stiffened curved panel, with its excellent property, is widely used in the engineering fields of aeronautics and astronautics, and its layout optimization design is concerned increasingly by the researchers.This paper reviews the structure optimization design method and its development course, introduces several common types of the stiffened curved panel, the basic concept of buckling and the development status of the stiffened curved panel layout optimization design. Then, a two-level layout optimum design method is developed for the stiffened thin-walled curved panel layout optimization problem. At the first level, with certain layout variables and shape variables, using the parametric modeling method, the size of the structure is optimized with the optimizer in Nastran and the responses are got, the responses include the weight and the buckling factor. At the second level, based on the design of experiment and the approximate model, The initial samples of layout variables and shape variables are created by the design of experiment. Then, the size variables of initial samples are optimized with the finite element analysis. The responses corresponding to the initial samples are computed. The initial Kriging models are derived through these samples, as well as the updated Kriging models are derived with the updated samples, Furthermore the optimal solution is obtained by the multi-island genetic algorithm based on the Kriging model.Using the above two-level layout optimum design method, the stiffened curved panel, the stiffened cylindrical shell and the stiffened thin-walled cone are optimized, and corresponding parametric modeling programs are finished, The result shows that the method can reduce weight and find out the approximate global optimal solution effectively. The method proposed in this paper is proved to be efficient and practical by comparing the final result with the initial solution.