Nonlinear aeroelastic fluid-structure-acoustic interaction analysis of a coupled composite panel with an acoustic cavity in supersonic flow

This paper is concerned with numerical modeling and nonlinear dynamics analyses of fluidstructure-acoustic interactions of an elastic composite laminated panel with a backed cavity in supersonic flow. To achieve strongly coupled solutions to the aeroelastic fluid-structure-acoustic interaction problem, an implicit partitioned arbitrary Lagrangian-Eulerian solution method is developed based on a finite volume model for the supersonic flow and a monolithic nonlinear finite element model for the composite panel-cavity system. A nonlinear higher-order shear deformation zig-zag theory is adopted to accommodate the large-deformable vibration of the composite panel, and the acoustic wave equation is employed for modeling the compressible fluid in the cavity. The method is verified by comparisons with benchmark results. Physical insights into the effects of the dynamic pressure, cavity depth, and the ply-angle of composite material on the aeroelastic behaviors of the panel-cavity system are provided. Some new phenomena are revealed. A special flutter behavior dominated by acoustic resonance is found for the composite panel with a backed cavity in supersonic flow, which is due to local mode coalescence as the mode frequencies of the acoustic cavity and the composite panel are close to each other. The transition between the aeroelastic flutters of the composite panel induced by the lower-order structural mode coalescence and the acoustic resonance of the cavity can be progressively adjusted by alerting the cavity depth and the ply-angle of the composite panel.