Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Comparison of the sound absorption coefficient for three natural fiber samples with and without air gap using the impedance tube.
Submission Author:
Key Fonseca de Lima , PR , Brazil
Co-Authors:
Ana Carolina Mendonça Mansur, CLAUDIA BITTENCOURT, Marco Zeschotko, Nilson Barbieri, Key Fonseca de Lima, Fernando Jun Hattori Terashima
Presenter: Ana Carolina Mendonça Mansur
doi://10.26678/ABCM.COBEM2023.COB2023-2317
Abstract
Every day, humans are submitted to a set of sounds of the most different natures, frequencies, and amplitudes. However, long exposure to these sounds can cause irreversible damage to their health. In purpose to control this undesired exposure, the application of green materials in noise control applications has been growing in the last decade. This work aims to evaluate the acoustic efficiency of sugarcane bagasse, hay, and coconut husk coir fibers in terms of their sound absorption coefficient between 200 and 5000 Hz. The evaluated samples have density and thickness of 190 kg/m3 and 30 mm, respectively. The fibers were bonded with white glue (polyvinyl acetate), and with a fiber/glue ratio equal to 10:9. The sound absorption coefficient was assessed using an impedance tube based on the ASTM E1050 standard. Furthermore, the samples were arranged inside the impedance tube with and without an air gap, between the rigid termination and the samples. Five samples of each fiber were manufactured, and the results showed that the sugarcane samples had higher absorption when compared to coconut and hay. However, the sound absorption peak for the three fibers was at 1600, 1200, and 800 Hz, respectively. Finally, the air gap addition at the back of the sample increased sound absorption after the first absorption peak and moved it toward the low frequency.
Keywords
sound absorption, natural fibers, ASTM E1050, air gap, Coconut fiber, sugarcane fiber, hay fiber
