A novel aeroelastic test rig for large-amplitude, 3-DOF vibration testing of slender structures at arbitrary wind attack angles

Conventional spring-suspension techniques of section-model wind tunnel tests have inherent limitations, including stiffness misalignment with the model’s principal axes, strong mechanical nonlinearity under large oscillation amplitudes, and inapplicable to large wind angle of attack. To address these challenges, a novel aeroelastic test rig is developed to enable large-amplitude, three-degree-of-freedom (3-DOF) coupled vibration of slender structures under arbitrary wind angle of attack, while maintaining low structural nonlinearity, weak DOF coupling and stiffnesses aligned with the model’s principal inertia axes. A pair of streamlined, airfoil-shaped end-walls are also designed to minimize end effects and house the elastic-suspension system and sensors. Theoretical formulations are developed for the nonlinear stiffness and equivalent mass of the elastic support system for practical design. The engineering case study of an H-shaped hanger demonstrates good performance of the proposed test rig in reproducing large-amplitude 3-DOF coupled aeroelastic instabilities. The proposed test rig offers a robust platform for studying nonlinear aeroelastic responses of slender structures such as hangers, cables, and bridge decks under arbitrary wind angle of attack.