A super-element of track-wheel-terrain interaction for dynamic simulation of tracked vehicles

A track-wheel-terrain interaction model is presented in this paper, which can be used as a "force" super-element in a multibody dynamics code for dynamic simulation of tracked vehicles. This model employs a nonlinear finite element representation for the track segment that is in contact with the terrain and roadwheels, which can be used to simulate two different track systems, namely a continuous rubber band track and a multi-pitched metallic track, provided the finite element mesh in the track model is properly defined. The new track model accounts for the tension variations along the track (due to the non-uniformly distributed normal pressure and traction), track extensibility, and geometrically large (nonlinear) track deflections. A new solution algorithm is then proposed that includes an adaptive meshing method for representing track movement during the simulation for the multi-pitch tracks. Doing so produces a track model that captures high-frequency content of the track-wheel-terrain interaction, and it can more accurately describe the mechanics of a multi-pitch track as the vehicle negotiates rough terrain. The resulting track-wheel-terrain model combines approximate and known constitutive laws for terrain response with the new track representation, which allows the computation of the normal and shear forces, as well as the passage frequency, at the track-terrain interface. The track model and solution algorithm are further illustrated in this paper using a simple two-wheel system model and a full vehicle model of an M1A1 tank.