Structural design of composite stiffened panel for a flat wing micro-aircraft

Abstract

In this study, the integral micro-sized composite wings are designed and manufactured by using carbon fiber reinforced plastics and low-density foam. The analytical expressions of bending stiffness of a multilayer sandwich structures for variable cross-section panel are determined. The obtained analytical bending stiffness is numerically verified using results of compressive buckling modes on wing panels from a numerical FE program and experimental tests by a series of stiffened structures which are empirically designed. Contrastive results demonstrate that the stiffener configuration tremendously affects the global buckling of the wing panels and the shapes, locations and intervals of the stiffeners which should be adjusted to construct a structure with maximum bending stiffness. Finally, with the use of the bi-directional evolutionary structural optimization method, the optimum design of the wing cross-section was determined by topology optimization method to pursue the best weight/stiffness. Compared with the initial structure, the optimum material layout of the topology structure performs better at reducing stress concentration and improving load carrying capacity of wing panels.