Prediction of the dynamic response and fatigue life of panels subjected to thermo-acoustic loading

This paper focuses on the formulation and validation of a reduced order model for the prediction of the response - displacements, stresses, fatigue life - of aircraft panels subjected to a severe thermo-acoustic loading. The reduced order modeling starts with a finite element model from a standard package (MSC.NASTRAN) and produces a set of cubic nonlinear differential equations which are efficiently marched in time. The basis for the representation of the displacement field includes transverse deflection modes of the linear panel and some associated in-plane modes (the dual modes). A partial static condensation approach is proposed for the numerically efficient integration of the reduced order model governing equations. Validation cases demonstrate the accuracy of the proposed static condensation and of the good to excellent reliability of the reduced order model for the prediction of the displacements and stresses of panels in the nonlinear range in static and dynamic cases. The computational efficiency of the reduced order model permits the generation of time histories of stresses long enough for the accurate assessment of the fatigue life of panels.