| Keywords |
Membrane material ; Sound absorption coefficient ; Air permeability |
| Abstract |
Membrane structures are widely used for constructing large space such as gymnasium and stadiums. The use of sound absorption membrane system are increasing in stadiums and arenas, however research on the sound absorption characteristics were not so much investigated. Kiyama (1996), Hashimoto (1996) and Sakagami (2005) conducted theoretical studies on the sound absorption and sound insulation properties of single and double leaf permeable membrane. In this study, sound absorption characteristics of each membrane were investigated by experiments in reverberation chamber. 4 types of permeable membranes and a non-permeable membrane were used for experiments. Air space behind membrane material and tension on the membrane was varied. Sound absorption performance of permeable membrane materials was investigated. As increasing air space behind the membrane material, sound absorption coefficient was increased. In a resonance absorption frequency band sound absorption coefficient varied more dramatically. Sound absorption characteristics were flat in mid and high frequency range and sound absorption coefficient was from 0.3 to 0.5. Also sound absorption coefficient was increased by the increment of surface density and air permeability of membrane. However, over the certain value of air permeability and surface density sound absorption coefficient was decreased. These results can be used as design factors and method for the room acoustic design of dome-stadiums and large free-form buildings. |