The paper contains an interim report on a research project into the longitudinal vibrations of vehicles. The aim is to improve understanding of the process by which tyres come to vibrate by rolling along surfaces which may be smooth or profiled and the transmission of the vibration into the vehicle cabin. A description of a specially designed rig is given. This allows control of the boundary conditions of a tyre / wheel assembly which runs on a rotating drum, and allows forcing to be applied by an electromagnetic shaker to the hub in the vertical or longitudinal direction. A measurement scheme has been implemented to record forces and translational and spin accelerations of the hub. A mathematical model of the rig has been built using the multibody modelling software Autosim. The tyre is represented as a hub and rigid circular ring with translational and rotational freedoms between them. The hub is mounted in a suspension system allowing it translational and spin freedoms. The model and the measurements are used to generate frequency responses, and a parameter identification scheme is being followed to obtain a best fit of the theoretical results to the experimental results in the frequency range up to about 100 Hz. Vibration spectra and comparative experimental and theoretical frequency response functions are included.
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