Simplified model for self-excited rear-axlevibrations

Vehicles are subject to a variety of requirements, of which the technical objectives are only a partial area. In addition, different sub-areas increasingly interact, whereby the complexity of the development process of a vehicle continuously increases.In the design phase, the vehicle characteristics are determined on a largely virtual level. In this phase no detailed final vehicle data is given. Instead, there are parameter ranges that are being progressively refined. Due to the available scope for development in the early phase, changes in vehicle parameters can still be achieved with arguable effort and manageable additional costs. However, complex full vehicle models that could be used to assess the effects of parameter changes with high accuracy are not yet available.During the testing phase, the vehicle functions and characteristics on the virtual vehicle are checked and assessed with regard to their goals. If target conflicts are discovered only during this late development phase, changes are associated with great efforts concerning engineering time and high costs due to the largely defined vehicle parameters.This conference paper presents a simplified simulation model with which statements regarding the self-excited oscillation phenomenon wheel shimmy can be made. With the help of a modified quarter-vehicle model unstable vibrations of the rear axle can be calculated. The instability assessment is done by an eigenvalue analysis.