Flutter analysis methods for bridges stabilized with eccentric wings
Journal of Wind Engineering and Industrial Aerodynamics 219: 104804 (2021-12-01)
Analysis methods for computing the flutter speed of bridges stabilized against flutter by stationary wings are presented. The wings are placed outboard the bridge deck to achieve a large lateral eccentricity, which enables them to produce enough aerodynamic damping to effectively raise the flutter speed. Given the focus on flutter, other wind effects are neglected. The analysis can thus be carried out in the frequency domain. The most sophisticated method is based on a specially developed finite aeroelastic beam element, used for modelling a bridge-deck-plus-wings segment, leading to a multi-degree-of-freedom analysis. Such analysis is recommended if the wings do not extend over the full length of the bridge, a design choice that benefits cost efficiency. Second, a simplified two-degree-of-freedom flutter analysis method is described. Simplification is achieved by establishing the wind forces on the wings assuming quasi-steady, instead of unsteady, flow and taking them into account as additional damping and stiffness. Results of example calculations are compared to those of the multi-degree-of-freedom flutter analysis. Finally, it is shown how torsional flutter of a bridge equipped with such wings can be treated in a single-degree-of-freedom analysis. The method is applied to the first Tacoma Narrows Bridge.
2-DOF flutter analysis
Aerodynamic damping device
Finite aeroelastic beam element
MDOF flutter analysis
Passive vibration control