Sound absorption performance of folded structures prepared from woven prepreg and porous material composites

In this study, a composite material composed of a woven prepreg and ventilated felt is designed and prepared in the form of a folded structure to obtain excellent sound absorption performance. Absorption experiments of the woven prepreg, composite material, and folded structure are carried out respectively. The test results show that the composite material has a higher minimum value of the sound absorption curve compared with woven prepreg, which is further improved by the folded structure. The sound absorption coefficient of the structure can be greater than 0.4 in the 400–6300 Hz range. Meanwhile, a theoretical model is established according to the characteristics of the folded structure, which shows good agreement with the experimental results. Finally, the theoretical model is used to analyze the three key factors (thickness of the composite, height of the whole structure, and folding angle) in the design of the folded structure. The results show that increasing the first two factors can significantly change the sound absorption performance of the structure, while the folding angle will not significantly change the sound absorption characteristics of the structure.