A Comparative Analysis of Acoustic Absorbers for Automotive Application

different types of nonwovens, namely, layered spunlaced, needle-punched and chemically bonded layers of needle-punched and spunlaced nonwovens were compared with commercial samples. Effects of types of layering, web bonding techniques and pore characteristics were investigated on normal incidence sound absorption behaviour of nonwovens. Pore size and its distribution were measured, and structures of the samples were observed under the scanning electron microscope. The result indicates that by selecting appropriate technologies lighter nonwovens can be developed with improved acoustic properties. A three-layer spunlaced 2 nonwovens (800 g/m and 3.39 mm thickness) showed a statistically significant improvement in acoustic coefficient (α). The three-layer spunlaced nonwovens α was 0.42 as compared to α 0.22 of the commercial 2 sample (1200 g/m and 6.09 mm thickness) in the overall frequency range of 50–5700 Hz