Identification of flutter derivatives of bridge deck under multi-frequency vibration

Abstract

A multi-frequency vibration method (MFVM) is proposed to identify flutter derivatives of bridge deck. In this method, a bridge deck is forced in vertical or torsional harmonic vibration with linear combination of multi-frequency. Computational Fluid Dynamic (CFD) simulation is conducted using 2D unsteady incompressible Navier-Stokes equations combined with renormalization group (RNG) k-e turbulence model, based on improved domain decomposition method. The non-dimensional time histories of lift and moment are fitted by least square method to identify the flutter derivatives of bridge deck. Flutter derivatives of a thin flat plate and the 2nd Nanjing Yangtze River Bridge section are computed. The results are in good agreement with Theodorsen's theory and wind tunnel test data, which demonstrates the reliability and efficiency of the present approach.