Modelling and experimental investigation of multilayered nonwoven-microperforated foil hybrid panels for advanced sound attenuation

Abstract

This study investigates the acoustic performance of singular and multilayered nonwoven absorbers, with particular emphasis on the integration of flexible aluminium microperforated foils (MPFs). Experimental testing combined with empirical modelling was employed to characterise their sound absorption behaviour. For acoustic behaviour of multilayered nonwoven configurations, homogenised equivalent-fluid modelling was developed with optimising the power-law constants using particle swarm optimization (PSO) algorithm. The results demonstrate that increasing the number of layers, while maintaining constant thickness or areal density, enhances sound absorption due to viscous, thermal, and structural losses, as well as phase shift and impedance matching between intermediate air layers. Compression of multilayered structures was found to reduce internal air cavities, leading to diminished absorption and a shift of peak performance toward higher frequencies. The incorporation of MPFs, engineered with structural damping and mass end correction modification to Maa’s model, yielded significant enhancement in low- and mid-frequency absorption. Moreover, the placement and number of MPFs within multilayer assemblies were shown to modulate both the magnitude and frequency of peak absorption. These findings provide valuable insights for designing advanced insulation materials that combine thermal management with improved acoustic comfort in automotive, industrial, and building applications.