Determining the Sound Absorption Coefficient of Bamboo Composites: Theoretical- and Laboratory-based Approaches

Aim: 
The use of natural fiber-based composites in various applications is increasing due to their cost-effectiveness, low density, nontoxicity, and environmental friendliness. Therefore, in this study, the acoustic performance of natural bamboo fiber composites was investigated using experimental and theoretical methods. The properties of these composites, which include affordability, low density, nontoxicity, and eco-friendliness, contribute to their growing popularity.
Methods: 
In this study, three types of composites with a density of 200 kg/m³ and thicknesses of 50 mm were fabricated. The normal incidence absorption coefficient was directly measured using the impedance tube method based on the ISO 10534-2 standard. In addition, for predicting the sound absorption coefficient of the composites, the software COMSOL and the Miki and Attenborough models were utilized.
Results: 
The results indicate that for samples F (fine fiber) and F-C (fine coarse fiber), the average sound absorption above 1000 Hz is 0.8. The sound absorption values in sample C (coarse fiber) were lower than those in samples F and F-C. In addition, the mathematical models of Miki and Attenborough can predict the acoustic behavior of the samples to some extent, with the Attenborough model providing higher accuracy in its predictions.
Conclusion: 
The results of this study demonstrate that a composite composed of natural bamboo fibers can be used as a sound-absorbing material for noise control purposes, while also contributing as a green technology replacing natural fibers with synthetic fibers.