Reduction in High-Frequency Wheel Noise/Vibration of Railway Vehicles Using Piezoelectric Shunt

We propose the application of a resonant shunt to wheels to reduce the high-frequency wheel noise generated by railway vehicles. High-frequency wheel noise is caused by the resonance of wheels owing to contact between rails and wheels. A resonant shunt is applied at specific frequencies to reduce wheel resonance. In this work, the high-frequency noise generated by a wheel moving on a curved railway track was analyzed and compared with the dynamic characteristics of the wheel. Further, to reproduce the high-frequency noise of the wheel, an external electric signal was input to a piezoelectric patch connected to the wheel to generate noise and vibration at the natural frequency of the wheel. The optimum mounting position of the piezoelectric patch was determined by numerically analyzing the strain energy of the wheel. Piezoelectric patches were connected to their respective resonant shunts to form a vibration reduction array. A synthetic inductor was tuned to effectively reduce the high-frequency vibration and noise of the wheel generated at its natural frequency. In the wheel excited at its natural frequency, vibration and noise were reduced by approximately 4-10 dB and 8-12 dB(A), respectively. In the wheels that were simultaneously excited at two natural frequencies, vibration and noise were reduced by 5 dB and 5 dB(A), respectively. The results showed that the resonant shunt could effectively reduce the noise and vibration generated by the wheel. Therefore, the resonant shunt is an effective circuit system for reducing noise and vibration even in large structures.