Vibration damping system using active negative capacitance shunt circuit with piezoelectric reaction mass actuator

摘要

Boring bar (19,20) vibration damping is improved by a novel use of the electromechanical properties of the piezoelectric actuator material (17). A negative capacitance shunt circuit (35) is provided in which a voltage-controlled voltage-source continuously simulates a negative capacitance that is substantially equal in magnitude but opposite in phase to the capacitance of the piezoelectric material (17). The negative capacitance is shunted across the piezoelectric device (17), effectively compensating for the capacitance of the device across a broad frequency band. The voltages generated in the piezoelectric element in response to mechanical deformation induced by broadband vibrations of the structure during damping operations, may then be completely resistively dissipated., thereby enhancing the mechanical damping.