Vibration Reduction by Passive and Semi-Active Friction Joints

Reduction of structural vibrations is of major interest in mechanical engineering for lowering sound emission of vibrating structures, improving accuracy of machines and increasing structure durability. Besides optimization of the mechanical design or various types of passive damping treatments, active structural vibration control concepts are efficient means to reduce unwanted vibrations. In this contribution, two different semi-active control concepts for vibration reduction are proposed that adapt the normal force of attached friction dampers. Thereby, semi-active control concepts generally possess the advantage over active control that the closed loop is intrinsically stable and that less energy is required for the actuation than in active control. In the chosen experimental implementation, a piezoelectric stack actuators is used to apply adjustable normal forces between a structure and an attached friction damper. Simulation and experimental results of a benchmark structure with passive and semi-actively controlled friction dampers are compared for stationary narrow-band excitation.