A simple first-order shear deformation theory for vibro-acoustic analysis of the laminated rectangular fluid-structure coupling system

This paper presents a simple first-order shear deformation theory (SFSDT), which is used for the first time to analyze the vibro-acoustic characteristics of the laminated rectangular plate-cavity coupling system filled with air or water. The proposed theory contains only four unknowns and has greater application scope and higher computation accuracy compared with the classical plate theory (CPT). The admissible functions of displacements and sound pressure of the fluid-structure coupling system are expressed as superposition of the periodic functions based on the Fourier series method. Combined with the artificial virtual spring technology, the proposed theory could be used to analyze the composite coupling system under various combinations of classical boundary conditions or arbitrary elastic boundary conditions. Based on the free vibration analysis of the laminated rectangular plate in-vacuo, both the natural characteristics analysis and the forced response analysis under the excitation of a unit point force or a unit point sound source are carried out. The differences between the weak coupling system with air as medium and the strong coupling system with water as medium are discussed in detail and some new results and new conclusions have been given, which could be the benchmark for the future research.