Vibro-acoustic response of sandwich plates with functionally graded core

Abstract

This paper presents the vibro-acoustic modeling and analysis of sandwich plateswith metal–ceramic functionally graded (FG) core using a simplified first-order shear deformation theory and elemental radiator approach. A simply supported rectangular plate having functionally graded core, metal and ceramic facesheets is considered with aluminum as metal and alumina as ceramic. The material properties of the core are assumed to vary according to a power law distribution of the volume fraction of the constituents. The sound radiation due to point load and uniformly distributed load is computed by numerically solving the Rayleigh integral. The effective material properties of the sandwich plate are presented as a function of core thickness. The vibration parameters in terms of natural frequencies, plate displacement and velocity, and acoustic parameters such as radiated sound power level, radiated sound pressure level and radiation efficiency are computed for various values of the power law index. A comprehensive study of the influence of core thickness on vibro-acoustic performance is presented in terms of mean-squared velocity and overall sound power level. It is found that, for the plate being considered, the sound power level increases with increase in the power law index of the core at lower frequency segment. Increased vibro-acoustic response is observed in the high-frequency band for ceramic-rich FG core and in the low-frequency band for metal-rich FG core, respectively. A sandwich plate with metal-rich FG core configuration has shown improved flexural stiffness, compared to an FG plate with no significant rise in overall radiated sound. It is possible with this analysis to suitably tailor and optimize the sandwich FG plates for multifunctional performance and desired vibro-acoustic interaction.