A new vibration damping method using a semi-passive control

A new damping system, based on piezoceramics shunted with a specific time sequence, is presented: Unlike ofher passive devices, the dissipation does nof occur in a resistance or in a resistor/inductor circuit. The basic idea is to adequately deform the piezo output voltage waveform in order to create a phase shift between the output voltage and the mechanical displacement. The voltage distortion is obtained by switching from short circuit to an open circuit configuration in a repetitive sequence synchronous with the mofion. The switching removes periodically the electric charges from the piezoelectric elements, changes the mechanical overall stiffness and creates non-linearities, thus creating several dissipations mechanisms. Experiments have been run on a cantilever device equipped with ceramic plates and a switching network. The results show a damping level higher that what is achievable with a passive circuit approach. Furthermore, the proposed approach works over a large bandwidth thus leading to important reduction for transient vibration.