Optimization and sound absorption modeling in Yucca Gloriosa natural fiber composite

Introduction: Nowadays, the acoustic behavior analysis of natural fibers composites has received increasing attention by researchers. In this regard, the present study aimed to optimize and model the sound absorption behavior of composites made of Yucca Gloriosa (YG) fiber via using a mathematical modeling approach. Methodology: In this experimental cross-sectional study, in order to fabricate the natural acoustic composites, the alkaline treatment of the fibers was employed. In this study, the design of experiments and determination of the optimum amount of alkaline treatment parameters (NaOH concentration and immersion time) to improve the sound absorption was performed by Response Surface Methodology (RSM).  Moreover, the sound absorption coefficient (SAC) of YG fiber was measured by an impedance tube system (ISO10534-2 standard). The applicability of Delany-Bazley (DB) and Miki analytical models for predicting the sound absorption coefficients of the natural composites by coding formulas in MATLAB software was investigated as well. Result: Comparison of the obtained SAC showed that this value of optimized was higher than untreated composite at all frequencies, and the sound absorption average (SAA) index increased by 18.92%, particularly when compared to the raw composites. Also, good agreement was found between the results from the empirical models and the experimental results in the low and mid-frequency range of one-third octave band. Conclusion: the optimization of alkaline treatment and prediction of SAC by empirical model, with regard to the prominent benefits of natural fibers and the wide use of these fibers, is considered as an acceptable strategy for acoustic applications (industries and buildings).