STUDY ON THE VERTICAL STIFFNESS AND DAMPING COEFFICIENT OF TRACTOR TIRE USING SEMI-EMPIRICAL MODEL

An experiment was conducted to determine the vertical stiffness and damping characteristics of tractor tires for the aim of simulation and design of the tractor suspension system. Three kinds of tractor tires were selected to measure vertical stiffness and damping coefficient by using Free-Vibration Logarithm Decay Method at five levels of tire inflation pressures and two tire loads. The results show that, for all kinds of tire, the stiffness was linearly increased by increasing tire inflation pressure whereas the damping coefficient decreased when tire inflation pressure increased. The stiffness and damping coefficient of tractor tires also depend on the tire size, the structure of tires as front tire or rear tire. Additionally, the damping coefficient shows the increasing trend while the increase in tire stiffness is not clear by increasing tire load. The results also reveal that the appropriate distribution of tire load, tire inflation pressure and tire size can change significantly the tire stiffness and damping coefficient to control tractor vibration. Keywords : Tire stiffness; Damping coefficient; Tractor tire; Tire inflation pressure.