Low consumption damping of planar structures

The synchronized switch damping (SSD) is a semi-passive damping technique, based on an intermittent switching of piezoelements bonded on a mechanical structure. It corresponds to a proper chopping of the voltage across the piezoelements in order to get it in phase with the vibration displacement speed thus resulting in an efficient damping. A 20 dB damping can be obtained with a 2 mW electrical consumption for a steel cantilever. The damped energy being independent of the frequency range, the SSD technique works nicely for transient regimes. The paper, after a presentation of the method and previous results, deals with the extension of the method to planar resonant structures. Damping results, in the low frequency regime are shown for the fundamental flexural mode and its overtones. The problem of energy transfer from mode to mode due to the non-linear control of the voltage signal is addressed and discussed. Theoretical arguments are given to interpret the experimental results