Vibro-acoustic characteristics and response analysis of composite laminated stiffened cylindrical shell-acoustic cavity coupled systems under multi-source excitations

Abstract An analysis model for the vibro-acoustic characteristics and response of a coupled system is established, consisting of a composite laminated stiffened cylindrical shell and an enclosed cavity. The first-order shear deformation theory (FSDT) and an improved Fourier series are employed to construct the displacement admissible functions for the composite laminated stiffened cylindrical shell and the pressure admissible functions for the cylindrical cavity. This study uses artificial virtual spring technology to simulate arbitrary supported and coupled boundary conditions. The energy functionals for the composite laminated stiffened cylindrical shell and the cavity coupled system are established. The vibro-acoustic characteristics of the coupled system are obtained by introducing the Rayleigh-Ritz method to solve the energy equation. The accuracy of the proposed theoretical model is verified by comparing its predictions with results from finite element model (FEM). Furthermore, the model is validated through comparisons with experimental test data. Based on this, the specific effects of shell thickness, curvature radius, layup angle sequences, and stiffener number on the natural frequencies and sound pressure response are analyzed. The vibro-acoustic coupling response of the coupled system under multi-source excitation is analyzed by introducing internal point force excitation and point acoustic sources. This study provides a theoretical foundation for predicting and understanding vibration and noise in this class of structural systems, which is a crucial prerequisite for any noise reduction design.