Highly flexible flight vehicle aeroelastic and aero-viscoelastic flutter issues.

Aeroelastic and aero-viscoelastic phenomena arising from the high flexibility of modern flight vehicles are examined, and governing relations are formulated and solved. In particular, the time dependent flight velocities associated with maneuvers and with in-plane bending are considered, which necessitate new derivations of the Theodorsen function, unsteady aerodynamic relations and equations of motion. Under these conditions, simple harmonic motion (SHM) is no longer achievable and different flutter criteria based directly on motion stability are presented. The viscoelastic problem is formulated in terms of integral partial differential equations with variable nonlinear coefficients. Their solutions and evaluations are discussed in detail. One interesting departure from linear responses emerged, which indicates flutter in one bending while the other bending mode and the torsional are both stable. A detailed and extended treatment of these subjects may be found in [1]. [ABSTRACT FROM AUTHOR]