Study on the variation characteristics of vertical equivalent damping ratio of tire-soil system using semi-empirical model

摘要

Prediction and determination of the damping ratio of a tire-soil system is very important to the design of the suspension system of the tractor. With this aim, a test rig was designed and developed to measure the vertical equivalent damping ratio of tire-soil system using Free-Vibration Logarithmic Decay Method. The test was performed with three kinds of tractor tire using a combination of five inflation pressure levels, three soil depths and four soil moisture contents in the paddy soil. The results revealed that the vertical equivalent damping ratio of tire-soil increases with the increase in soil depth and decreases with the increase in tire inflation pressure. It also increases with relative increase in soil moisture contents (observed at 37.9%, 48.8% and 66.7% soil moisture content) then decreases as soil moisture content is too high (observed at 77.4% soil moisture content). So, it is concluded that the vertical equivalent damping ratio of tire-soil system is evidently dependent on tire inflation pressure, soil moisture content and soil depth. These have to be noticed and used in design parameters of tractor suspension system.