Study on sound insulation performance of the periodic arrangement expansion chambers structure with built-in micro-perforated panel

Abstract

The periodic arrangement expansion chambers structure with built-in micro-perforated panel (MPP) is proposed. The transmission loss (TL) of expansion chambers before and after the introduction of MPP is analyzed by transfer matrix method and finite element method. In the low frequency range, the TL curves obtained by the transfer matrix method and finite element method are consistent. Both show that the first pass frequency of the structure disappears and the sound insulation bandwidth of the structure widens obviously after the introduction of MPP. The influences of the parameters of the periodic expansion chambers structure on the TL are numerically analyzed. By making hole on the inserted MPP, ventilation cooling function is realized. The result shows that the overall sound insulation effect is still satisfying after making appropriate hole. Additionally, expansion chambers and double MPP with hole insertion structure has been constructed. The result shows that the second pass frequency of expansion chambers structure also disappears. Therefore, the sound insulation performance of the expansion chambers structure is further improved by adding double-layer MPP. The sound insulation performance of the periodic expansion chambers structure with ventilation capability is tested by laboratory experiments. Excellent sound insulation ability is confirmed.