Physical investigation on the sound transmission loss of heterogeneous metastructures using wave-based methodologies

Abstract

Existing methodologies employed for computing acoustic indicators of heterogeneous metastructures have limitations in terms of accuracy and efficiency, especially for metastructures showing complex phenomenon that involves the interaction between different wavetypes (flexural, shear, and high-order waves), which significantly influences the sound transmission characteristics of the structure. The present study focuses on providing an efficient wave-based methodology to study the wave coupling effect and the accurate estimation of Sound Transmission Loss (STL) of these metastructures. It develops the Wave Finite Element (WFE) scheme to compute the STL by applying a plane wave excitation from the ambient fluid domain to a representative Unit Cell (UC) of the periodic structures, this methodology is also exploited to study the sophisticated phenomena of wave coupling on the accurate computation of acoustic indicators. STL under Diffuse Acoustic Field (DAF) is computed by integrating the wave STL over all possible incidence angles. Various configurations, laminated glass with Polyvinyl Butyral (PVB) core, sandwich plates with a Shape Memory Polymer (SMP) core, sandwich plates with a thick soft core, Cross-Laminated Timber (CLT) plate, and a curved structure configuration, are presented to highlight the advantages of the proposed wave-based methodology for investigating the physics of sound transmission in heterogeneous metastructures.