Study on Vibration Analysis about an Agricultural Machinery Excited by Tire Lugs

Unstable Vibration from Non-linear Isolation Rubber

Abstract

Knowing the vibrational behaviour of tractors is necessary to modify driving safety and comfort. The purpose of this paper is to understand vibration phenomena using simulation models, which include the peculiar characters of tractors. By the experimental results from static tests, the model of the isolation rubber is obtained. The tire lugs, which are taken as the excitation source, excite the tractor at specific frequencies due to their profiles. Using a quarter and a half-size model about the body, we determine the model parameters based on the commercial lists. We calculate the acceleration responses accelerating from zero to 16 m/s and decelerating inversely. From calculations about accelerating, it is found that the resonance phenomena continue. Because the stopper part of the rubber, where the cabin connects to the frame, has higher stiffness than isolation part, so the resonance frequency increases following the increase of the excitation frequency. We could show that unstable vibration may occur in the accelerating state of tractors by nonlinear characteristics of the isolation rubber.