Several approaches have been developed over the years for the modelling of the tyre behaviour in vehicle-dynamic applications. The so-called ‘rigid-ring’ models are among the classics for the modelling of the belt dynamics. Although there are several works dealing with the vibrating properties of tyres, the problem of the identification of the related rigid-ring model parameters has not been described other than qualitatively or partially. The aim of this work is thus to fill this gap and to devise a procedure for the experimental characterisation of such parameters, namely the frequency and damping of the in-plane and out-of-plane belt vibration modes as well as the associated masses and inertias. An experimental modal analysis (EMA) approach is employed, which involves an instrumented hammer combined with three-axial accelerometers roving on 16 stations equally spaced along the tyre circumference. The method is numerically demonstrated on the finite-element models of a motorcycle tyre and a car tyre. The approach is also experimentally validated on a real tyre. The rigid-ring vibration modes of the motorcycle tyre are in the range 70–220 Hz, while those of the car tyre are in the range 51–85 Hz. The ratios of the mass/inertia of the rigid ring to the mass/inertia of the tyre are in the range 40–87% and 68–74% for the motorcycle and car respectively.
One of the most used tyre models is the so-called Magic Formula, which provides the contact forces and moments as a function of the tyre slips and normal load. Among the slip inputs, there is the spin–slip, which is defined as the combination of a camber component and a path-curvature component. The two components are related to each other by the camber reduction factor, for which only a few data have been reported in the literature. In addition, these data are often obtained from indirect measurements. In this work, an experimental procedure for the direct measurement of the camber reduction factor was devised, and applied to six specimens of motorcycle tyres (three front and three rear). The approach employs a rotating-disk machine, where the tyre is intrinsically subjected to path curvature. A specific aligning procedure to mitigate sideslip disturbances is introduced and employed during testing. The three specimens of the rear tyres tested showed a camber reduction factor that was close to zero, which is the typical result suggested by the literature. On the contrary, the three specimens of front tyres showed slightly negative values, i.e., the camber component increased with respect to the curvature component. The results suggest that the classic assumption of a zero camber reduction factor does not hold valid for all motorcycle tyres.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.