Abstract

The plunge galloping is a high-amplitude, low-frequency oscillation of a slender structure, such as iced conductors of a power transmission line or bridge decks, essentially perpendicular to the wind direction. In the paper, an idealized model for the plunge galloping is shortly reviewed and then a slight modification of the variational iteration method, applicable to weakly nonlinear problems, is employed to obtain a system of two amplitude-frequency equations that provide both the transitional and long-term behaviours. The approximate analytical results derived in the paper have been applied to a typical section model and the numerical results are contrasted with those provided by the direct integration of equation of motion.