Suppressing Brake Vibrations by Deliberately Introduced Damping

Most brake vibration phenomena are caused by self-excitation based on friction forces between pad and disk respectively drum. Brake vibrations are in general undesired as they often cause noise or uncomfortable structural vibrations. In automotive industry such phenomena are summarized by “Noise, Vibration, Harshness” (NVH). The actual DFG priority program “Calm, Smooth and Smart” intended to investigate countermeasures against such phenomena with special focus on damping. In fact, damping is known to be an effective countermeasure against self-excited vibrations, if the self-excitation itself cannot be avoided or active interventions are too costly. Therefore, in the current project the influence of damping on brake vibrations is thoroughly investigated. In the first period the focus was on the investigation of the modeling and influence of so called shims, thin composite structures applied on the backplate of disk brake pads, while in the second period the influence of related damping devices on drum brakes was considered. For both considered systems and in both periods experiments as well as simulations were performed. The shim investigations especially focus on homogenization methods for Finite Element models. Variations of shim set-ups are considered to investigate the corresponding damping effects and their influence on systems’ behavior is studied. Both experimental studies and simulations show that damping can be an effective countermeasure against brake vibration phenomena like squeal, if corresponding devices are thoroughly designed and placed.