Sound Radiation Responses and Acoustic Behvior of Sandwich Panel

Abstract

Sandwich structures with decent sound insulation and absorption properties have been widely used in the engineering fields such as aerospace engineering, marine engineering and civil and construction engineering. Investigations on the acoustic behavior of sandwich structures is of practical importance, not only for engineers but to researchers in the field. A numerical study of the vibro-acoustic and sound transmission loss (STL) of an aluminum honeycomb core sandwich panel with fabric-reinforced graphite (FRG) composite face sheets is performed in the present research. The honeycomb sandwich structure, faced with an FRG composite face sheet, has acoustic advantages over other types of sandwich structures commonly used in the field. The effects of different boundary conditions and geometric properties of the FRG faced honeycomb structure on the stiffness of the structure are evaluated. The effects of the stiffness on the acoustic performance of the structure are investigated. Truss core sandwich panels filled with sound absorbing materials are also studied numerically for the panels’ vibration responses and STL behavior. The performances of a polyurethane (PUF)-foam-filled truss core sandwich panel and a wood-board-filled truss core sandwich panel are compared. The wood based sandwich panel shows advantages with compatible acoustic performance and environmental-friendly characteristics over the PUF foam panel. The acoustic behavior of the wood-based porous media, with varying airflow properties, are investigated. The most significant factor affecting the vibro-acoustic responses of the panel are identified. The wood-based-porous-medium-filled truss core sandwich panel with various face sheet materials are analyzed. A truss core 2 sandwich panel is designed with the optimal combination of wood-board and face sheet materials. Numerical models, based on the sandwich theory, are established based on the assumption the sandwich core is an orthotropic structural layer. The radiated sound power from the panel is quantified with the Rayleigh integral method. A random diffuse field is used as an incident sound source and is derived with the finite element method using ACTRAN. The numerical results generated with the implementation of the models are validated with experimental data available in the literature. The findings provide guidance for selecting and designing honeycomb core and truss core sandwich panels with decent acoustic properties for engineering applications. The developed approach presents practical significance for quantitatively evaluating and designing sandwich panels with high efficiency and effectiveness, when the acoustic and vibrational performance of the panels need to be considered.