Optimization and sound absorption modeling of Yucca Gloriosa natural fiber composites

Abstract

Background and aims: The use of natural fibers brought fundamental changes to natural fibers production, considering its vast environmental, physical, mechanical, and sound absorbing qualities. Nowadays, considering their new revenue at absorbing sound, the acoustic behavior analysis of natural fibers composites, called "The Green Fibers", has received increasing attention by researchers. In this regard, the present study is aimed to optimize and imitate the sound absorption behavior of Yucca Gloriosa (YG) composites via using mathematical imitation and optimization approach. Methods: In order to fabricate the natural acoustic composites, in this experimental cross-sectional study, the alkaline treatment of the fibers was employed. Therefore, the design of experiments and determination of the optimum amount of alkaline treatment parameters (NaOH concentration and immersion time), was promoted to improve the sound absorption by Response Surface Methodology (RSM). Moreover, the sound absorption coefficient (SAC) of YG fiber was measured by an impedance tube system (ISO10534-2 standard). To predict the sound absorption coefficients of the natural composites, the applicability of Delany-Bazley (DB) and Miki analytical models was investigated by coding formulas in MATLAB software as well. Results: Comparison of the obtained SAC showed that, the value of optimized composites was higher than the untreated ones at all frequencies. Particularly, when compared to the raw composites, the sound absorption average (SAA) index increased by 18.92%. Also, a good compatibility was found, between the empirical models' and the experimental results in the low and mid-frequency range of one-third octave band. Conclusion: With regard to the prominent benefits of natural fibers and the wide use of these fibers, the optimization of alkaline treatment and prediction of SAC by empirical models, is considered as an acceptable strategy for acoustic applications (industries and buildings).