Sound transmission characteristics of a composite sandwich plate using multi-layer first-order zigzag theory

This study investigates sound transmission through a composite sandwich plate with a soft core. Vibro-acoustic governing equations based on a new simple multi-layer first-order zigzag theory (MFZT) are presented. The transverse shear deformations of the face layers and core are described by different shear deformation theories, satisfying the interface's continuity condition. First-order shear deformation theory (FSDT) is used for the top and bottom layer face, while linear functions are used to model the transverse and in-plane displacements of the soft core, respectively. The vibro-acoustic governing equations are derived based on Hamilton's principle. The suggested model can accurately predict the vibration and sound transmission loss (STL) of the soft core composite sandwich plate under simply supported. The accuracy and convergence of the present model and numerical solutions are validated versus available studies. On that basis, the vibration and STL of composite sandwich plates with soft cores are studied, and the influence of parameter changes (face layer ply angles, incident elevation angles, face layer/core thickness and density) on the STL is discussed. The results show that the material properties can significantly affect the sound transmission loss and peak/valley frequencies of a composite sandwich plate with a soft core.