Influence of soil deformation on off-road heavy vehicle suspension vibration

Analyses of the dynamic behaviour of a heavy vehicle during off-road operation are conducted under steady state condition. Three different numerical quarter-vehicle models (single point contact model, rigid wheel contact model and deformable wheel contact model) are introduced, and the simulation results are compared in order to find the most appropriate vehicle model. During the longitudinal travel of the vehicle, arbitrary ground profile is an input of vertical excitation to the vehicle. When ground deformation is included in the numerical model, the deformation filters the vertical excitation to the vehicle while the level of excitation varies depending on the soil deformability. Bekker's non-linear pressure/sinkage relationship is applied in modelling the ground behaviour. The simulations are conducted in the time domain and various surface roughness and ground deformability are applied in the ground/vehicle interaction during a parameter study. The ground deformation under the wheel acts like a non-linear spring during the vehicle movement and influences the vehicle vibration. If a vehicle mainly operates on off-road condition with high ground deformability lower value of damping is required in order to minimise the vertical body acceleration.