Sound absorption of a flexible micro-perforated panel absorber based on PVDF piezoelectric film

Micro-perforated panel (MPP) has been widely used in the noise control field. However, the performance at low frequencies is relatively poor due to the restricted space limitations in actual applications. Hence in this paper a flexible micro-perforated panel absorber (PVDF-MPPA) based on Polyvinylidene fluoride (PVDF) piezoelectric film is proposed, which is composed of a perforated aluminum-electrode PVDF piezoelectric film and a small air cavity. Its sound absorption at low frequency can be improved by employing panel vibration effect and shunting the electrodes of piezoelectric film with some electrical impedance. The corresponding structure of the PVDF-MPPA was designed and fabricated. Experiments were performed under different shunting cases such as open circuit, short circuit, and resonant circuit in an impedance tube with the testing frequency range from 100 Hz to 1600 Hz. The results demonstrated that the PVDF-MPPA with shunt circuits had a wider absorption bandwidth compared with a rigid MPP absorber with the same structural parameters. When compared with the open circuit and short circuit cases, the PVDF-MPPA with resonant circuit definitely has a better low frequency absorption performance if the shunting parameters have been carefully tuned. By using shunt-damping technology, the PVDF-MPPA has a potential to be widely used as an efficient sound absorber in practical situations because of its simple structure and good absorption performance at low frequencies.