Effect of an Optimized Fiber Orientation on Transonic Flutter Characteristics of a High-Aspect-Ratio Composite Wing

摘要

The feasibility is examined of using a direct search method, which does not depend on the flutter velocity derivative, to find the optimum fiber orientations which maximize the flutter velocity of a composite wing. The Sequential Simplex Method, as one candidate for such a method, was applied to the design of a transonic flutter model of a high-aspect-ratio transport wing, and was proven to be very effective in finding the optimum fiber orientation to give the maximum flutter velocity. The experimental verification of this has also been conducted in the National Aerospace Laboratory (NAL) 0.6 m x 0.6 m transonic blow down tunnel, by flutter tests with two kinds of models; i.e., one with an optimum fiber orientation, and one without. The experimental results have shown that the flutter velocities of the optimized model are about 60 percent higher than those of the non-optimized model over the entire transonic Mach number range tested.