On the Avoidance of Friction Induced Vibrations by Structural Optimization

Rotors show very rich dynamical behavior especially when friction is involved. Due to the interaction of nonconservative, dissipative and gyroscopic forces a very interesting stability behavior can be observed. Instability of the rotor can yield severe problems, for example in the context of brakes and clutches it causes squeal, in the process of paper calendering the duration of the rollers is decreased substantially. This paper deals with the problem of how to design a rotor such that it is robust against friction induced vibrations using structural optimization. The problem is addressed using discrete and continuous models for disk brake squeal. It is shown that a proper design of the brake rotor can passively suppress squeal without introduction of additional damping into the system. Many of the qualitative results carry over to other problems of friction induced vibrations in rotors.