Low-Frequency Noise Reduction Using a Piezoelectric Sound Absorbing Panel Using LR Circuit and Applied Voltage

This paper proposes a method of low-frequency noise reduction using piezoelectric elements. The piezoelectric element on the panel shunted with an inductance and a resistance works like a mechanical dynamic vibration absorber. Using this panel, low-frequency noise can be reduced. Further, by applying voltage that is related to displacement of the host structure to a piezo-electricelement, sound absorbing effect can be improved. Normal incidence sound absorption coefficient was theoretically formulated. Then, optimum values of the inductance and resistance were theoretically derived for two cases: one is the case to absorb noise of specific frequency, the other is the case to maximize amount of absorbed energy when noise that has uniform power spectrum such as white noise is incident. Effectiveness of the proposed method was investigated through simulations and experiments.