The influence of tyres on the dynamic behaviour of a lawn mower

Agricultural tractors are used for on-road and off-road transport purposes, for supplying the necessary power during held operations and for controlling the mounted implements. Unfortunately, soil undulations induce tractor and machine vibrations, reducing driver's comfort and their capability of controlling the linked machinery. In this introductory study, the effect of some characteristic parameters, such as tyre pressure, and herewith related tyre stiffness, and mass addition on the dynamic behaviour and, more specifically, on the resonance frequencies of a lawn mower, are analysed by experimental modal analysis. After adapting the modal model, field unevenness instead of disturbance forces could be introduced as excitation inputs. A final validation of the adapted modal models shows good agreement with measured lawn mower vibrations. (C) 1997 ISTVS.