Nonlinear Response of Composite Panels Under Combined Acoustic Excitation and Aerodynamic Pressure

Abstract

A e nite element formulation is presented for the analysis of the large dee ection response of composite panels subjected to high acoustic excitation and aerodynamic pressure at supersonic e ow. The e rst-order shear defor- mation theory is considered for laminated composite plates, and the von Karm´ an nonlinear strain -displacement relations are employed for panel large dee ection response. The e rst-order piston theory aerodynamics and the simulated Gaussian white noise are employed for the aerodynamic and acoustic loads, respectively. The nonlinear equationsofmotion foranarbitrarily laminated compositepanelsubjectedto combined aerodynamicand acoustic pressures are formulated e rst 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 dee ned 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 dee ections, dee ection 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.