Analytical Model for the Turning of Tracked Vehicles in Soft Soils

Abstract : An analytical model has been developed for the steady state turning of tracked vehicles in soft soils. The tracks of the vehicle are modeled by a series of rigid plates, each representing track lines directly loaded by the roadwheels. The action of the track links in between the directly loaded ones is represented by a surcharge pressure. The soil is modeled by its Coulomb strength parameters; the interface between soil and track is characterized by the interface friction angle and slip. Track-soil interaction models have been developed separately for the outer track (driving mode) and inner track (braking mode), using plasticity theory for the determination of soil reactions. The slewing forces needed to overcome the turning resistances are determined iteratively. The yaw center offset is determined on the principle that it minimizes the turning resistance. Examples show the applications of the model for the determination of turning resistance, maximum speed of steady state turning and horsepower requirement for various military vehicles and soil conditions. (Author)