REDUCED-ORDER MODELING OF THE RANDOM RESPONSE OF CURVED BEAMS USING IMPLICIT CONDENSATION (PREPRINT)

Abstract : Accurate prediction of the response of aircraft skins to acoustic loading is important in the design of future air vehicles. Much work has been reported in recent years on prediction methods which reduce a finite element model to a reduced-order system of nonlinear modal equations. This body of work has shown good results for predicting the random response of flat structures. However, there have been few studies reported on reduced-order methods applied to structures with shallow curvature. Curvature complicates the analysis by introducing linear coupling of transverse and in-plane displacements. The implicit condensation and expansion (ICE) method, which eliminates the need for normal membrane vectors in the modal basis, has been shown to give accurate results for flat structures. This paper presents the results of a numerical study of the ICE method to predict the response of a thin, curved aluminum beam to random distributed loading. Power spectral densities of transverse and in-plane displacement from the ICE method agree very closely with those from direct integration of a full finite element model.