The research article 'Experimental investigation on the noise reduction of an axial piston pump using free-layer damping material treatment' has been published in Elsevier journal Applied Acoustics.
Discrete-frequency tones at integral multiple of the pumping frequency are often the main contributor to the noise of axial piston pumps. It is an effective method to reduce the noise by suppressing the discrete-frequency tones. In this study, the most dominant discrete-frequency tone of an axial piston pump was suppressed using free-layer visco-elastic damping material treatment. The noise and vibrations of the axial piston pump were experimentally measured and analyzed at several steady-state operating conditions. Dramatic reductions in the noise and vibrations were found. In particular, the noise and vibrations at the 2nd harmonic at the rated speed of 1500 r/min were significantly reduced. An experimental modal analysis (EMA) was conducted to identify the cause of the reductions in the discrete-frequency tone. The EMA result showed that one prominent natural frequency around 457.8 Hz of the untreated pump increased to around 484.5 Hz of the treated pump. The increase of the prominent natural frequency contributed greatly to the decrease of the modal displacement, leading to the reductions in the vibration and noise.
The study shows the feasibility of using the free-layer visco-elastic damping material for potential applications of reducing the vibration and noise of hydraulic displacement pumps.