Author(s): Guojun Huang; Pengfei Liu
Linked Author(s):
Keywords: Ice-induced vibration; Compliant structures; Frequency lock-in; Resonance; Ice-crushing strength; Strain rate effect
Abstract: This paper presents a theoretical investigation on the mechanism of the frequency lock-in and resonance observed in the ice-induced vibration (IIV) of compliant structures. The study is based on a dynamical model of IIV developed recently by authors (OMAE2006). It is shown that in addition to the conventional resonant frequency lock-in, there exists another type of the frequency lock-in, namely, the separated frequency lock-in, where the predominant frequency of ice force is not locked on the natural structural frequency. Besides, the influence of some important ice and structural properties on the frequency lock-in is studied. From these theoretical studies, it is turned out that the strain rate effect of the ice-crushing strength is responsible for the frequency lock-in and resonance. A self-exciting vibration comes from the strain rate effect through the uneven momentum transfer between ice and structures, dependent on the relative movement directions. The self-exciting vibration is coupled with the forced IIV in a complex nonlinearly dynamical way, leading the system to the stationary vibration with the feature of the frequency lock-in. These theoretical results are instructive to the further systematic experiment study on the frequency loc-in and resonance, and useful for us eventually to devise some effective techniques for the mitigation of intensive IIV.
Year: 2008