Measurement and Frequency Analysis of Dynamic Vertical Wheel Load of Farm Tractor

Abstract

Field experiments investigated the vertical wheel-load variations of the left rear wheel of a tractor driven at different combinations of static loads and tire pressures. The dynamic wheel load was measured on rigid and deformable grounds using strain-gage-based transducers. Frequency analysis presented a combination of the effects of the ground profile and tire characteristics on wheel-load variations. On an asphalt road, both the nonuniformity of the wheel-tire assembly and tire lugs excited the wheel-load variations at their first- and second-order frequencies, while these self-excitations had less effect as the ground deformability increased during the tests on sandy loam and clay soils. However, the nonuniformity of a low-pressure tire moving on extremely deformable clayey field critically affected the wheel-load fluctuations.