Wind Tunnel Experiments on the Divergence of Swept Wings with Composite Structures.

摘要

An elastic wing with variable sweep was designed and subcritically tested for aeroelastic divergence in the Virginia Tech six foot stability wind tunnel. This wing has an internal interchangeable graphite/epoxy plate that provides the wing stiffness. This plate had the shape of a high aspect ratio trapezoid with a line of symmetry coincident with the spanwise reference axis. A fiberglass aerodynamic shell with ten chordwise sections surrounds the plate. These shell sections were mounted so as to minimize their stiffness contribution to the plate and still maintain good aerodynamic performance. A series of six symmetric plates with various fiber orientations were constructed. Fiber layup on each plate is symmetric about the midplane parallel to the surface. By inverting the plate, it was possible to test 11 unique fiber orientations. Theoretically, identified test results predicted relationships between wing sweep, fiber orientation, and divergence speed. One configuration, tested to the divergence speed, showed good correlation with the subcritically projected divergence speed. (Author)