Acoustic Response of Sigmoid Functionally Graded Thin Plates: A Parametric Investigation

Abstract

Purpose: This paper presents a parametric investigation of the sound response of a thin sigmoid functionally graded material plate using the classical plate theory and Rayleigh integral with the elemental radiator approach. Method: The material properties of the plate are assumed to vary according to the sigmoid law (two-power law) distribution of the constituent materials in the transverse direction. The sigmoid functionally graded material is modeled using a physical neutral surface instead of a geometric mid surface. The effects of the sigmoid law index, elastic modulus ratio, different constituent materials, damping loss factor, and boundary conditions on the sound power and sound radiation efficiency of a sigmoid functionally graded plate are analyzed. Results: For the very-low-frequency range, lower than the first lowest resonant frequency, sigmoid law index, modulus ratio, boundary conditions, and damping loss factors do not significantly influence the sound power level and sound radiation efficiency. However, the sigmoid law index significantly influences sound power level and radiation efficiency in a broader operating frequency range considered here (greater than the first resonance frequency). Conclusions: There exists a critical value of the power law index and modulus ratio, for which the corresponding peak of sound power level is minimum. The different values of damping loss factors do not significantly influence sound radiation efficiency for the given material constituents of the sigmoid functionally graded plate. However, the selection of material constituents of sigmoid functionally graded plates influences the radiation efficiency peak. © 2022, Krishtel eMaging Solutions Private Limited.