In this paper modelling techniques are applied to interpret some significant experimental observations on the ice-induced vibration of a flexible structure. The analysis is intended to promote physical understanding of the phenomena underlying ice-structure interaction. In the first part, harmonic components involved in the structural response are identified. In the second part, damping effects on the predominant frequency of structural response are investigated with a set of analytic solutions. It was found that the predominant frequency increases with the ice velocity up to a certain value below the natural frequency of the structure, while the average crushing force decreases with the ice velocity.