Nonlinear response of composite panels under combined acoustic excitation and aerodynamic pressure

A finite element formulation is presented for the analysis of the large deflection response of composite panels subjected to high acoustic excitation and aerodynamic pressure at supersonic flow. The first-order shear deformation theory is considered for laminated composite plates, and the von Karman nonlinear strain-displacement relations are employed for panel large deflection response. The first-order piston theory aerodynamics and the simulated Gaussian white noise are employed for the aerodynamic and acoustic loads, respectively, The nonlinear equations of motion for an arbitrarily laminated composite panel subjected to combined aerodynamic and acoustic pressures are formulated first in structure node degrees of freedom. The system equations are then transformed and reduced to a set of coupled nonlinear equations in modal coordinates. Modal participation is defined and the in vacuo modes to be retained in the analysis are based on the modal participation values. Numerical results include root mean square values of maximum deflections, deflection and strain response time histories, probability distributions, power spectrum densities, and skewness and kurtosis, Results showed that combined acoustic and aerodynamic loads have to be considered for panel analysis and design at high dynamic pressure values.