Models of Tire-Road Contact Deformation and Cavity Acoustics for Rolling Resistance and Road Noise

A structural FEM model of tire rolling resistance due to tire hysteretic deformation loss was developed using both non-linear material properties and rolling contact characteristics. The tire design used was so-called the next generation tire with large diameter, narrow width and high inflation pressure. The FEM model was verified by a new method of measuring the tread inner surface temperature distribution using infrared camera in real rolling conditions. As a result, tread shoulder was found to play the most important role in rolling resistance by dissipating strain energy. Further, a computation model of sound waves in a tire cavity coupled with tread vibration was developed using FDTD (finite difference in time domain) method. This model can estimate the forces acting on the wheel from acoustic waves in the tire cavity. This model was verified by experiments in which cavity acoustic waves and tread inner surface vibration waves were measured in rolling conditions. As a result, asymmetrical distribution of acoustic pressure on a wheel rim was identified as the excitation force of cabin road noise.