Development of hybrid layered structures based on natural fabric reinforced composites and warp knitted spacer fabric for acoustic applications

This study deals with the development of hybrid layered structures combining natural fabric reinforced composite plates and warp knitted spacer fabric for acoustic applications, and the evaluation of the sound absorption performances. Vacuum infusion technique was used to produce the composite plates. Jute and linen woven fabrics were used as reinforcing materials, and they were impregnated with epoxy resin. The composite plates were combined with warp knitted spacer fabric in different stacking sequences in three-layer structures. All samples were subjected to the measurement of sound absorption property using impedance tube method. The combinations of a single layer and double layers of warp knitted spacer fabric with natural fabric reinforced composite in the appropriate sequences were found to provide superior sound absorption coefficients (SAC) compared to non-hybrid layered structures. Based on the overall evaluation regarding SAC, noise reduction coefficient (NRC), and weight of the structure, the sample with the best performance was regarded as the double layers of spacer fabric backed with a jute fabric reinforced composite plate. The integration of natural fabric reinforced composites with warp knitted spacer fabric had better sound absorption performance compared to the glass fabric reinforced composites, and they were considered to have the potential of being used in interior noise control mainly in vehicles and buildings.