The Influence of Curved Profiles on the Vibro-Acoustic Characteristics of Light-Weighted Sandwich Shell: An Analytical Solution

Abstract

The overall aircraft noise is significantly minimized using curved light weighted sandwich shells as an airframe element. However, there is a lack of studies on how the curvature can influence vibro-acoustic characteristics. To the best of our knowledge, this paper presents an analytical solution that predicts the vibro-acoustic characteristics of simply supported light-weighted sandwich shells with various curved profiles for the first time. Natural frequencies, displacement and velocity responses, sound pressure level (SPL), sound transmission loss (STL), and radiation efficiency are the critical parameters when analyzing vibro-acoustic characteristics of any structure and are presented in this paper. The generalized kinematic equations are established for the sandwich shells, and the governing differential equations are derived using Hamilton’s principle. The solutions are obtained using Navier’s method, and the vibration response is determined by solving the first five unknown mode coefficients. The Rayleigh Integral is used to extract the acoustic responses and is validated. In addition, the effect of face sheet to core thickness ratio [Formula: see text] of curved sandwich shells on vibro-acoustic characteristics is critically examined and presented. It is found that introducing the positive curvature to the sandwich shell reduces the bending moment, thus improves improving the vibro-acoustic characteristics in the lower frequency range. An increase in the [Formula: see text] enhances the shell’s vibro-acoustic characteristics until a threshold value [Formula: see text], beyond which the mass contribution deteriorates the characteristics. For a hyperbolic paraboloid shell [Formula: see text], this effect was observed at a lower-frequency value of 425[Formula: see text]Hz.