Abstract:

A novel beetle’s elytra-inspired lightweight structure is used as the stiffeners of the skin-stiffened structure with large cutout in the aircraft. According to the requirements on the mechanical and thermal properties of such stiffeners, the objective functions are built respectively, which all are nonlinear, so the response surface method is chosen to obtain the approximation models of the three objective functions and the sample points are determined by Latin hypercube sampling experimental design method, whose properties are figured out through building FEM parameterized model and numerical simulation. Based on the approximation models, the multi-function cooperative optimization design is performed and linear search method is used to obtain the optimized properties of the inspired structure, whose heat dissipation and compressive resistance ability are 14.3 and 2.1 times respectively as the non-optimized ones, also its dynamic property is improved dramatically, and its weight is lighten by 11% with same load bearing. Furthermore, taking the first-order buckling factor and the maximum displacement of this skin-stiffened structure with large cutout as two constrain conditions, and total structure weight as objective function, the response surface method is applied again to obtain the approximation models, and the genetic algorithm is used to work out the optimized layout of stiffeners. According to optimization results, the total structure weight is lessened by 15%, at the same time, the first-order buckling factor is 1.02, increased by 21%, and the maximum displacement is 12.1 mm, decreased by 20%, demonstrating the optimization design is very effectively.

Key words: large opening area, layout optimization, multi-functional optimization, response surface method, bio-inspired structure