Acoustic properties of natural fiber reinforced composite micro-perforated panel (NFRC-MPP) made from cork fiber and polylactic acid (PLA) using 3D printing

The present study investigated the acoustic performance of biodegradable MPP absorbers made of natural fiber-reinforced composites (NFRC) using 3D printing. The novelty of this current research lies in the recent development of a methodology that aids industry professionals in optimizing the production of MPP (Micro Perforated Panel) at a competitive cost. This is achieved by addressing and eliminating various issues commonly faced in traditional manufacturing processes, such as manual preparation and pressing. The FDM technique was used to fabricate test samples utilizing the PLA/corkwood composite. Using an impedance tube device with two microphones, the acoustic absorption coefficients of MPPs with different perforation diameters, thicknesses, and perforation rates were measured. Maa's analytical model was used to predict the acoustic absorption performance. Moreover, considering the average sound absorption and total cost of fabricating the samples, RSM-CCD was employed to optimize these samples. In the end, the parallel arrangement of MPP double layer and the combination of MPP with kenaf porous material were tested in order to improve the sound absorption performance. The results showed that the average sound absorption coefficient of the NFRC-MPP sound absorber is 25 % more than that of conventional MPP sound absorbers. The sample with a perforation diameter of 0.70 mm, a panel thickness of 0.90 mm, and an 8 mm distance between the perforations was selected as the optimal sound absorber. The measurement and model data for NFRC-MPP panels do not correspond well. The parallel arrangement of two layers of MPP and the addition of an optimized kenaf layer behind the MPP significantly improved the sound absorption performance in the intended frequency range. The findings of this study, coupled with data available in the literature for other types of biocomposite Micro Perforated Panel (MPP), strongly indicate that Cork fiber-based MPP exhibits substantial promise for application, either independently or in conjunction with Kenaf materials, as a material for acoustic conditioning. Implementing smart manufacturing techniques for acoustic panels not only enhances engineering noise control efforts but also amplifies the overall effectiveness of Hearing Conservation Programs.