Aeroelastic Flutter and Divergence of Graphite/Epoxy Cantilevered Plates with Bending-Torsion Stiffness Coupling

摘要

The aeroelastic flutter and divergence behavior of rectangular, graphite/epoxy, cantilevered plates with varying amounts of bending-torsion stiffness coupling is investigated for incompressible flow. A general Rayleigh-Ritz formulation is used to calculate flexibility influence coefficients, static deflections, divergence velocities, vibration frequencies, and flutter velocities. Flutter calculations are done using the U-g method. Test plates were constructed and subjected to static, vibration and wind tunnel tests. Wind tunnel tests indicated static deflections, divergence instabilities, bending-torsion flutter at low angles of attack, and stall flutter at high angles of attack. Bending stiffness and first bending frequencies showed good agreement between theory and experiment. Torsional stiffness and first torsion frequencies were not accurately predicted by the theory for highly coupled plates. Divergence velocities and reduced flutter velocities showed reasonable agreement between theory and experiment. Test plates with varying amounts of coupling exhibited markedly different stall flutter characteristics. (Author)