Vibration and noise reduction of axial piston pump based on negative capacitance piezoelectric phononic crystal structure

Currently, the primary methods for reducing the noise of piston pumps are to optimize the shell structure of the pump and increase the damping. However, with a change in the primary noise frequency of the piston pump, these methods cannot control the noise reduction in real-time, leading to the development of existing piston pump noise reduction methods in engineering applications. In this study, the vibration and noise reduction method of piezoelectric phononic crystals (PPCs) plate structure laid on the piston pump shell is proposed. First, a dynamic model of a piezoelectric phononic crystal (PPC) was established, and a new PPCs plate structure was designed. The effects of circuit parameters on the bandgap and vibration transmission spectrum characteristics of a PPCs plate were analyzed using the finite element method. It is determined that the series negative capacitance shunting circuit can adjust the low-frequency broadband gap attenuation vibration of PPCs plate. Subsequently, a dynamic model of the mechanical liquid coupling of the axial piston pump was established, and its accuracy was verified experimentally. The vibration and noise effects of laying and not laying PPCs plates on the piston pump were analyzed and compared. The results showed that the vibration of the PPCs plate laid on the piston pump has obvious attenuation in the frequency range of 50–1000 Hz. In comparing the average total sound pressure level of the external field radiation noise of the two, the amplitude is reduced by 4.76 dB (A), and the main noise frequencies of the piston pump are significantly reduced.