Abstract: A rigid-elastic coupling model is established and the vibration analysis method is presented for researching the in-plane characteristic of heavy duty radial tire with aspect ratio of about 1. The experimental modal test and analysis methods of coupling between carcass and sidewall are proposed, and the coupled natural frequencies are analyzed with the normal pressure and fixed rim. The rigid-elastic coupling equation is modeled with the flexible beam on the foundation that the carcass is modeled as the Euler beam and the sidewall is regarded as the sub-sectional spring with lumped mass. The dynamics equation is dispersed using finite difference method, and three-parameters model is derived based on the geometrical and structural parameters. The structural parameters of tire are identified by the genetic algorithm based on the experimental modal parameter of heavy duty tire, and the higher order modal frequency is predicted using the analytic method. The analytical transfer functions between carcass and carcass, and carcass and sidewall are derived. Experimental and theoretical results show that the rigid-elastic coupling model can be used accurately to predict the transfer function and vibration feature of heavy duty tire within the frequency band of 300 Hz, compared with the method in which only the coupling of carcass and rim is considered, and is limited to 180 Hz. Key

Key words: heavyloadedradialtire, in-planerigid-elasticcoupledmodeling, transfercharacteristic, finitedifference, experimentalmodalanalysis