Hybrid acoustic panel: the effect of fiber volume fraction and panel thickness
The composite panel test were made of gypsum, pumice powder, and glue with composition of 1:2:1/2 and coconut fiber with volume fraction variation of 10%, 15%, 20%, 25%, and 30% by using Hand lay-up technique. The sound absorption panel was tested for acoustic and mechanical characteristic using test standard with ASTM E1050, ASTM D256, and ASTM D790, respectively. The result of data analysis was presented graphically and the bounding of composite materials was analysed by using SEM photograph. From the data analysis for 10mm thickness of composite with 30% fiber volume fraction gained the highest sound absorption coefficient, the highest impact strength occurred on composite with 25% fiber volume fraction. Meanwhile, the strength and modulus of bending occurred on composite with 15% fiber volume fraction. Sound absorption coefficient for composite with 15mm thickness was higher than 10mm for 10% fiber volume fraction.