Volterra series based model for vortex-induced vibration of Bridge Decks

A truncated Volterra series based nonlinear oscillator is introduced to model the vortex-induced vibration (VIV) of bridge decks. Typical features of VIV such as the "limit cycle oscillation" (LCO), "hysteresis" and "beat phenomenon" are parsimoniously and accurately captured in the proposed nonlinear model. As a functional expansion of a nonlinear system, Volterra series is convenient for estimating the linear and nonlinear contributions to VIV. It is demonstrated that the relative contribution of nonlinear effects in VIV is around 50 percent of the total response for a range of bridge cross-sections. The efficacy of Volterra series as a reduced order model (ROM) in capturing aerodynamic nonlinearities eliminates the need for reliance on conventional phenomenological models as it promises to offer a unified framework for nonlinear wind effects on long span bridges, e.g. VIV, buffeting and flutter.