Torsional wave suppression in metashaft with shunted piezoelectric rings

This study investigates the bandgap tunability of a metashaft with periodic shunted piezoelectric rings. An analytical model based on the Bloch theory and the transfer matrix technique is developed to predict bandgap characteristics and the transmission of torsional vibration in the proposed structure. The location and width of the bandgap can be easily tailored by altering the electric parameters of shunt circuits. Compared with other shunt assemblies, the use of the negative capacitance resonant shunt enables the creation of a lower bandgap with a relatively wide bandwidth. Bandgap frequencies have a strong dependency on the inductance and capacitance but not on resistance. Moreover, the frequency with an unbounded loss factor coincides with the one of maximum attenuation. Multiple bandgaps can be achieved by adding extra sets of shunt circuits to the metashaft. Theoretical results have been validated by comparing them with finite element results. Our findings provide feasible guidelines in the design of torsional active control systems.