Modeling Tracked Vehicles Using Vibration Modes: Development and Implementation

A full tracked vehicle model is developed with the objective of providing new capabilities in modeling track and suspension system dynamic response. This capability is essential for predicting the durability of the track as well as the vibration transmission to the interior of the vehicle. In this model, the track is represented as a continuous elastic member with longitudinal (stretching) and transverse track response described using low-order vibration modes. This modeling approach captures dynamic effects with few degrees of freedom relative to established multi-body dynamic formulations. Using this method, a full vehicle model involving relatively few degrees of freedom is assembled for an example military tank. A mixed Eulerian/Lagrangian description is employed wherein the rigid-body elements of the hull and suspension are coupled to component modes of the track spans. Implementation of this model within a commercial dynamics software package is accomplished through the development of a new force element for the track. This force element allows one to tailor the model fidelity to achieve particular simulation goals. As an example, the response of a tank maneuvering a bump course is evaluated. Calculated results include the dynamic track tension, normal contact forces, and vehicle acceleration levels. These results emphasize the importance of track vibration in tracked vehicle modeling and illustrate advantages in using a modal representation for the track.