Method for the rapid evaluation of vehicle mobility on unpaved terrain

In cases where the mobilization of vehicle convoys in off-road conditions are considered, the mechanism of soil-vehicle interaction emerges as the key parameter controlling the travel time along the chosen route. Therefore, this paper proposes a new simplistic method that would allow the rapid evaluation of vehicle mobility in off-road conditions based on soil topography and vehicle characteristics. This method considers the limit equilibrium of soil under the loading conditions imposed by an accelerating vehicle and by natural terrain geometry. The influence of surface topography on soil’s stress state is considered by modifying the dynamic fluidization theory. In this paper it is proven that the underlying assumptions of the fluidization theory are very well suited to define the nature of stress rotations in sloping ground and the resulting geometry of bearing capacity failure surfaces. Additionally, in order to consider the inertial effects and the effects of shear transfer between the vehicle and the soil, a Coulomb-type mechanism is adopted.