Corrected Aeroelastic Flutter and Divergence Analysis of Swept Wings with Stiffness Cross-Coupling

Abstract

The 1986 AIAA paper Control of Aeroelastic Instability Through Stiffness Cross-Coupling presented a derivation of aeroelastic flutter analysis for wings with stiffness cross-coupling, including forward-swept configurations. In applying the AIAA Journal of Aircraft formulation to practical design work, we identified five typographical errors that can lead to incorrect flutter and divergence velocities. Our paper re-derived the entire set of aeroelastic cross-coupling equations including the mass matrix, stiffness matrix, aerodynamic matrix, and vibration equations of motion, then identified and corrected the affected relationships. The corrected results express flutter velocity and divergence velocity as functions of the stiffness cross-coupling parameter and the torsional-to-bending stiffness ratio. Because the formulation applies to unswept, forward-swept, and rear-swept wings and fins in subsonic flow, these corrections are important for practical aeroelastic design and analysis. The corrected formulation is then compared with results produced from the unmodified published equations to show how the errors affect practical forward-swept, rear-swept, and unswept lifting-surface analyses for subsonic speeds.