Development of semi-active panel design for sound absortion

Abstract

Various noise-absorbing materials and apparatus were developed not only for industry purposes but also for increased personal convenience through the absorption of unwanted sound. Absorbing products are typically passive mediums, whereas active-control absorption is expensive and complicated to install. Thus, in this study, a semi-active panel design for the sound absorber is developed to ensure operation at a required absorption level for a particular environment and to allow manual control. This study focused on producing an optimum design from several blueprints by using the simulation program, WinFlag. Simulation results are validated by using the impedance tube method. The samples used are perforated plates with open areas of 5%, 7.5%, 10%, 12.5%, and 15%. The second layer is a 35-mm thick coconut coir fiber as the main absorbing material. The third layer is air cavity. Simulation results indicate that the panel with perforation plates with 15% open areas gained the highest peak of sound absorption coefficient (0.851) at 5000 Hz. By using 30 mm thick air cavities, the highest peak is 0.963 at 3129 Hz. Experimental results indicate that the highest peak of sound absorption coefficient is 0.847 for the 15% open area of perforated plates, whereas the highest peak is 0.934 when 30 mm thick air cavities are used. The same pattern in the overall results denotes that the experiment result agrees with that of the simulation.