Flutter derivatives for 1-DOF bridge decks using semi-flexible cantilevers

Identification of aeroelastic coefficients (flutter derivatives) is used in predicting the behavior of bridge decks subject to wind loading. Several methods have been documented for extracting these coefficients from wind tunnel tests, using both free and forced vibration cases, for decks attached to springs. In this talk we discuss extraction of flutter derivatives from soap film tunnel experiments using scale models of three bridge decks attached to cantilever beams. The system was modeled using the Euler-Bernoulli (EB) beam equation with an added mass at the tip. Results from the EB beam equation were used to estimate flutter derivatives for small amplitude vertical displacements. With the soap film tunnel we were able to observe both vortex-induced vibrations (VIV) and flutter for different bridge deck models, and we describe the transition between these two states in terms of the reduced velocity. We discuss how these results may be used to design vibration based energy harvesters.