Vibration control using harmonically-varying damping

This study proposes a new vibration control method using harmonically-varying damping. Previous research has demonstrated that resonance could be induced by the combination of a sinusoidal base excitation (not at the natural frequency) with harmonically varying damping. The amplitude and phase of the resulting resonance can be controlled through appropriate choice of variable damping. This finding is used herein for response control. A single degree-of-freedom structure excited by an external sinusoidal input disturbance is considered. An ideal variable damper is employed as a semi-active control device, in conjunction with a secondary base displacement, resulting in cancellation of the input disturbance. In this paper, an expression for the ideal damping required, as well as the secondary base displacement, are developed; the control performance is then confirmed through numerical simulation.