Design and experimental study of a highly efficient sound absorbing composite structure based on the perforated panel resonator with flexible tube bundles

The perforated panel resonator with flexible tube bundles was proposed in 2000. The tube bundles are incorporated into a cavity of the resonant perforated panel absorbing structure to extend its neck length. The predominant feature of this new sound absorbing structure is that it can improve the low-frequency sound absorption performance and effects. The perforated panel resonator with flexible tube bundles has been successfully used for some practical applications due to its excellent sound absorption performance. This paper proposes a high-performance composite sound absorbing structure based on the perforated panel resonator with flexible tube bundles. Utilizing the perforated panel resonator with flexible tube bundles, combined with the polyimide sound absorption material, the broadband sound absorption is realized through specific internal configuration arrangement optimization. In the limited space, not only the high frequency sound absorption effect is increased, but also the sound absorption band can be greatly extended to the low frequency range. The impedance tube experiment results show that the composite sound absorbing structure based on the perforated panel resonator with flexible tube bundles can achieve an average sound absorption coefficient of 0.95 in the frequency range of 160Hz-6300Hz. Its one-third octave sound absorption coefficient in the same frequency range reaches up to 0.906. It demonstrates a broadband sound absorption performance with excellent low frequency absorption properties.