Introducing the flap mass damper for controlling bridge aeroelastic instabilities

This study investigates the control of bridge deck flutter and torsional divergence instabilities, using a novel passive approach. The control system design study is based on a sectional flexible bridge model interacting with a constant velocity airstream. The control configuration incorporates the properties of movable flaps, seen as extensions of the bridge deck, and of a tuned mass damper (TMD). This combined mechanical system, referred to as the flap mass damper (FMD), combines favourable aerodynamic properties of the flaps with a driving force provided by the vibrating mass inside the hollow deck. A further advantage is that the deck’s motion is transmitted to the flaps passively without requiring complex external linkages. Special attention is given to ensuring that the control configuration attains optimum robustness properties and thus maximizes uncertainty tolerance.