RADIAL FORCE TRANSMISSION TO THE HUB FROM AN UNLOADED STATIONARY TYRE

The static and dynamic stiffness of a tyre sidewall are calculated as a function of geometry, load parameters and frequency. Two different expressions were used for below and above the ring frequency. The air pressure and section aspect ratio are found to be the controlling influences below the ring frequency. This sidewall stiffness was inserted into previously obtained wave equations to obtain the dispersion relationships and impedances for a tyre belt with sidewalls. The stiffness and force transmission to the hub in the region of the contact patch was also calculated and compared with measured values. The sidewall stiffness in the region of the contact patch is found to be strongly dependent on the belt wavespeed, giving a stiffer value in the region of the contact patch above the ring frequency.