Experimental comparison of absorption characteristics of single-leaf permeable membrane absorbers with different backing air cavity designs

• Takeshi Okuzono ^[1] ; Koji Uenishi ^[1] ; Kimihiro Sakagami ^[1]
  1. [1] Kobe University

     Kobe University

     Chuo-ku, Japón

     
• Localización: Noise Control Engineering Journal, ISSN 0736-2501, Vol. 68, Nº. 3, 2020, págs. 237-245
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • Permeable membranes (PMs), which are air-permeable fabrics made from various natural or chemical fibers that are thinly woven or non-woven, are attractive sound-absorbing materials. The simplest PM absorber is a single-leaf PM absorber (PMSG) with a non-locally reacting rigid backed air cavity in which a PM is placed in front of a rigidly backed air cavity. A honeycomb-backed single-leaf PM absorber (PMHC), which has a locally reacting air cavity, is also well known. However, the two PM absorbers have shortcomings in their diffuse field absorption coefficients attrib- utable to the backing air cavity design. To overcome those shortcomings, we intro- duce a PM absorber array (PMAR): a single-leaf PM absorber with multiple locally reacting air cavities of different depths. As described herein, to present PMAR benefits, we experimentally compare the diffuse field absorption charac- teristics of the three single-leaf PM absorbers with different air cavity designs. Reverberation absorption coefficient measurements were taken using nine thin permeable membranes made of three chemical fibers, each having different flow resistance and surface density. Results show that PMAR is an effective sound ab- sorbing structure to overcome the shortcomings related to the diffuse field absorp- tion coefficients of PMSG and PMHC. Material property effects on permeable membranes are also demonstrated.