Active vibration control in a two degrees of freedom structure using piezoelectric transducers associated with negative capacitance shunt circuits

The need for control or suppression of vibrations in mechanical structures has arisen because of their damaging effects on people, civil structures and machine parts. The present work aims to perform the vibration control of a portico type structure with two degrees of freedom, using piezoelectric transducers associated with negative capacitance shunt circuits with series electrical resistance. For this purpose, an electronic circuit with passive and active components associated with piezoelectric transducers QP10W was developed to produce a negative capacitance shunt circuit, implemented through Negative Impedance Converters (NIC) and using operational amplifiers. The response amplitudes of the system in the time domain and the frequency in free and forced vibration were analyzed in tests performed with and without shunt circuit operation in the system. Considering free vibration, a reduction of 9.01 dB was obtained for the first natural frequency and of 6.95 dB for the second one. For forced vibration, reductions of 1.5 dB were obtained for the first natural frequency and 2.19 dB for the second natural frequency, respectively. The vibration reductions obtained with the proposed system demonstrate the efficiency of the system.