Suppression of Self-excited Vibrations in Mechanical Systems by Parametric Stiffness Excitation

Self-excited vibrations in mechanical systems can be very dangerous for machines and structures. Therefore, means and methods to avoid or suppress such vibrations are of great importance. In this monograph the rather novel idea of employing parametric excitation for Vibration suppression is investigated thoroughly. By introducing a time­periodic stiffness parameter it is possible to enhance positive damping in the system and thereby cancel self-excited vibrations. Analytical methods are presented for an approximate stability investigalion of low­dimensional systems with periodic coefficients. For the most part a numerical method, based on slmulation, is used, to compute domains of stability for self-excited systems and decide on the effectiveness of the proposed method. Many results are presented for simple 2-degrees-of-freedom systems, but in the last chapter also a more complex rotor system is investigated.