Acoustic wave transmission of double-walled functionally graded cylindrical microshells under linear and nonlinear temperature distributions using modified strain gradient theory

Abstract

In this study, using modified strain gradient theory (MSGT) and the first-order shear deformation assumption (FSDA) framework, wave propagation through air-filled double-walled functionally graded (FG) cylindrical microshells subjected to linear and non-linear thermal loadings are investigated. MSGT has the advantage of having up to three scale parameters and can successfully reproduce size effects. The power-law model is used to express the distribution of material characteristics over the thickness of each shell due to characteristics varying by temperature, and the application of Hamilton’s principle results in deducing vibroacoustic equations in coupled relations. The size-dependent coupled vibroacoustic governing equations are solved using an analytical approach in conjunction with a double Fourier series, with the final result providing the appropriate Sound Transmission Loss (STL) equation. The developed solution’s accuracy and precision are examined by comparing it to data available from previous studies. Parameter studies reveal the impacts of temperature distribution, functionally graded index, incident angles, acoustic cavity depth, and length scale parameter on STL through double-walled FG cylindrical microshells.