Integrated optimization of hybrid-stiffness stiffened shells based on sub-panel elements

•Hybrid-stiffness stiffened shell is built to achieve simultaneous buckling pattern.•A novel hybrid model is developed to improve the computational efficiency.•An integrated optimization framework is presented for stiffened shells with cutouts.

A concept of hybrid-stiffness stiffened shell is proposed based on sub-panel elements to achieve a simultaneous buckling pattern, which can provide enhanced design flexibility to fully explore the load-carrying capacity of structures. Then, a novel hybrid model is established to improve the computational efficiency of post-buckling analysis for stiffened shells, where the Numerical Implementation of Asymptotic Homogenization Method is utilized to smear out the stiffeners. On this basis, an integrated optimization framework of sub-panel configurations and weld lands for stiffened shells is presented. Illustrative examples with single and multiple cutouts demonstrate the effectiveness of the proposed framework based on the concept of hybrid-stiffness stiffened shell.