Efficient reliability-based design optimization of composite structures via isogeometric analysis

Abstract

Composite variable-stiffness (VS) panels with curvilinear fiber paths are very promising for aerospace structures. Due to the inherent complexity of VS laminates, buckling analysis and design optimization are extremely time-consuming and challenging, especially when uncertainties are considered, i.e. reliability-based design optimization (RBDO). In this study, an efficient bi-stage RBDO framework via isogeometric analysis (IGA) is established to release the tremendous computational burden. In Stage I, the layer thickness and lamination parameters are used as design variables to obtain an approximated layer number, which greatly reduces the design variable size. In Stage II, intermediate density variables are introduced, and IGA is employed for the buckling analysis and derivation of the analytical sensitivity. Furthermore, the augmented step size adjustment (ASSA) algorithm is used to enhance the efficiency and robustness of the RBDO process. Numerical results of VS panels are used to validate the performance of the proposed RBDO framework. The optimal results indicate that the proposed framework can find the optimal lightweight design that satisfies the manufacturing constraints in an efficient and accurate manner.