Self-excited vibration analysis of a reduced-order model of a braked wheel with tyre, including suspension mechanism

This study is aimed at deepening the stability analysis of a braked wheel of a road car, including suspension mechanism, and focusing on the interaction effects between the friction characteristic of the brake and the force characteristic of the tyre. It is well known that both contact forces can independently lead to instability in their respective rotation dofs. However, it is of practical interest to understand their combined effects on stability regions, which hasn’t been investigated in literature yet. A minimal model with 5 dofs is proposed for the analysis, including the 2 dofs of the standard quarter car model (bounce of sprung and unsprung masses), plus rotation of the wheel rim and compliance of the suspension mechanism in both torsional and longitudinal directions. Stability analysis of the linearized model is performed with the aid of stability maps, highlighting sensitivity with respect to the governing parameters. In addition, the system’s modal behaviour is investigated as well.