Ground soil input characteristics determining agricultural tractor dynamics

Whole body vibrations are among the risk factors for professional diseases in agricultural operators: it is therefore fundamental to study vibration source dynamics to improve vehicle comfort and safety. This study analyses the forces acting on the tires of one tractor operated in 29 different settings both on a standard "ISO 5008" test track and three terrain surfaces. For each setting, the accelerations acquired at the tractor hubs were reproduced on a four-poster test bench and the vertical displacement of the actuators reproducing the test track was obtained for each surface. Subsequently, the spectra of the twenty-nine replicated ground inputs were analyzed. All of them showed a similar shape in terms of frequency, pointing out that solicitations originating from different agricultural surfaces belonged to a specific range of frequencies. Because of this, a remarkable simplification and standardization can be introduced in the analysis of tractor dynamics, comfort, and material resistance.