Experimental Modal Analysis of Towed Elastic Tyres During Rolling

The lateral vibration of towed wheels, the so-called shimmy, is one of the most intricate phenomena of vehicle system dynamics. In this paper, a simple mechanical model of shimmy is constructed from a towed elastic wheel with a perfectly rigid suspension system. The brief presentation of the mathematical model of the system is followed by the detailed experimental analysis. The physical parameters of a carefully designed experimental rig are determined in different experimental setups. The most relevant stability boundary of the straight-line stationary rolling is calculated theoretically and then validated by experiments. The vibration frequencies of the system in different parameter domains, with special attention to the stable regions, are investigated by the modal analysis of the towed tyre during rolling.