SIMPLIFIED ROTATING TIRE MODELS BASED ON CYLINDRICAL SHELLS WITH FREE BOUNDARY CONDITIONS

A number of studies have been previously concerned with vibrations of rotating tires. In order to capture detailed dynamics of a rotating tire, complex numerical models have been developed accounting for the non-homogeneous structural properties of the tire belt and sidewall, structural-acoustic coupling and complex geometry description (including that of the wheel rim), under varying rotation speeds. Although a remarkable amount of details can be successfully modelled using such an approach, it can be rather difficult to parameterize the model, i.e. to establish a clear-cut relationship between a geometrical or material property of a tire and the corresponding change in the tire dynamics. Thus an alternative approach is employed within the scope of this study by modelling simplified tire geometries. The focus of the study is put onto modelling vibrations of the tire belt, which could be approximated by a pressurised thin cylindrical shell having free boundaries. Then the mode shapes and resonance frequencies of the belt are calculated as functions of the material and geometrical properties of the shell and the speed of the shell rotation. The resonance frequencies and the mode shapes of the free rotating cylindrical shell could be used to form a foundation for the forced vibration response and thus offer a possibility to couple the free tire belt to models of the sidewall and the air cavity inside the tire using, for example, mobility-impedance based methods.status: publishe