Multi-layer fibrous structures for noise reduction

This review aims at gathering the available information of multi-layer fibrous structures toward acoustic absorption. Firstly, multi-layer nonwoven fabrics have attracted considerable attention of scientist and industries due to efficient noise reduction and economical production cost. Secondly, knitted and woven fabrics have different acoustic absorption mechanism with commonly used bulk fiber assemblies. This review critically examined both experimental investigations and theoretical analysis of multi-layer knitted and woven fabrics. Thirdly, multi-layer fibrous materials composed of nano-fibrous membrane and its unique advantages in noise reduction applications have been focused. Finally, we summarized the critical points and promising directions concerning the noise reduction properties of multi-layer structured fibrous materials.