Measurement, identification and modelling of damping in pneumatic tyres

This paper deals with a research approach specifically designed for the measurement, identification and modelling of damping in pneumatic tyres. As a less rigorous and more global approach of characterizing the engineering property of tyre damping, experimental modal analysis and methodologies based on both real and complex modes are introduced. In the context of the real modal analysis, the flexible ring tyre model is also investigated. A standard testing procedure is employed for the collection of vibration data in pneumatic tyres, and the linearity and reciprocity of the tyre structure and the orthogonality of its modes is proven at the initial stage of investigation. After demonstrating the disadvantages of the proportional damping assumption in describing the tyre vibration, the first-order complex modal interpretation with general viscous damping assumption is implemented and discussed, including an appropriate normalization of the complex modes. As a further extension to the analysis, the second-order Rayleighʹs small-damping approximation is introduced into the complex modes framework, in order to obtain an accurate global estimation of the damping distribution. atural evolvement of the applied damping models in this paper, from the simplest single-valued proportional damping in flexible ring tyre model, proportional viscous damping in real modal interpretation, up to the generally distributed viscous damping in second-order approximation of the complex modal interpretation, the finally identified damping matrices, both in modal and physical coordinates, present a reasonable explanation of damping effect in pneumatic tyres. Agreement between the theory and experimentally identified results also proves the suitability of this approach for damping identification in complex structures.