Highly Efficient Atmospheric Turbulence Response Analysis of Composite Aircraft Wings Using Pseudo-Excitation Method

Abstract

With commercial passenger airplanes becoming larger and larger and increased use of composite materials on aircrafts structures, random vibration analysis of structure for atmospheric turbulence effects has been become predominately important, which calls for highly efficient and accurate analysis methods to calculate the unsteady responses of this nature for estimation of fatigue lives under different operational conditions. Various mechanical and aerodynamic coupling between degrees of freedom need also be automatically taken into account. In this work an aircraft wing model is built by using composite laminate elements. The Dryden turbulence spectrum function is chosen as the input for excitation. The aeroelastic forces are calculated by the Theodorsen function. Imperfect correlation between excitations is automatically considered by using the pseudo-excitation method (PEM), an approach widely used in seismic engineering and wind engineering for fast random vibration analysis [1, 2]. By using PEM various aeroelastic coupling and mechanical coupling between degrees of freedom have been automatically included. The computational effort required is similar to those for harmonic excitation analysis, which can be fast handled for design purpose. A finite element program has been developed, which is purported for whole structure turbulence analysis of aircraft wings.