Research on modulation mechanisms of cantilever-structured Phononic Crystals integrating piezoelectric effects and localized defects

Abstract Controlling vibrations with varying frequencies is key to improving the riding comfort of vehicles. Thus, this paper studies cantilever-structured piezoelectric Phononic Crystals with tunable defect frequency within the low-frequency bandgap. Firstly, this paper proposes cantilever-structured piezoelectric Phononic Crystals, which is proven to possess a low-frequency bandgap of 310–395 Hz through the plane wave expansion method, finite element simulation, and experiments. Subsequently, by establishing a numerical model, performing finite element simulations, and conducting sample experiments, the mechanisms of modulating the electromagnetic oscillation frequency of the defect unit through a shunting circuit are analyzed. Finally, the defect unit with tunable electromagnetic oscillation frequency is incorporated into the perfect Phononic Crystals to create a point defect. It is verified that adjusting the circuit parameters of the external shunting circuit to modulate the defect frequency of the Phononic Crystals with defect unit and to apply it for filtering within the bandgap range is effective. The work presented in this paper provides an important reference for addressing low-frequency vibration control issues in the automotive industry.