Swept composite wing aeroelastic divergence experiments

The purpose of this paper is to illustrate by experimentation rather than analysis the potential effects of laminate design on wing divergence speed. Eleven flexible composite wing models have been tested for aeroelastic divergence at a number of fore and aft sweep angles. These fixed-root models incorporate sectioned aerodynamic shells mounted to interchangeable internal graphite-epoxy plates. These plates provide wing structural stiffness and simulate various off-axis composite structural configurations. Test results, obtained from subcritical testing using a modified Southwell method, clearly identify basic relationships between wing sweep, composite fiber orientation, and wing divergence speed. In addition, good agreement is shown between a Southwell prediction and a test actually run to divergence.