Natural frequencies and mode shapes of an automotive tire with interpretation and classification using 3-D computer graphics

Abstract

Natural frequencies and mode shapes of a radial tire have been obtained by using an efficient, 12 degree of freedom, doubly curved thin shell finite element of revolution with smeared-out properties of laminate composite materials. The finite element formulation includes the geometrical non-linearities so that the prestressed state of the tire due to inflation is taken into account. While the basic formulation follows that of earlier work done at Purdue University, a general and efficient computational procedure and program have been developed, with a main feature being integration with computer graphics. Thus the complex tire geometry can be modeled more accurately and the free vibration mode shapes can be displayed graphically. This allows an interpretation and classification of mode shapes beyond the classical mode shapes of tires that have been presented in the literature. It allows further insight into the relationship between transverse and tangential motions beyond what has been conceived at the present state of the art of experimentation. Theoretical results are compared with experimental results obtained from modal analysis and good agreement is shown.