Dynamic analysis of assembled aircraft structures considering interfaces with nonlinear behavior

Dynamic analysis is an essential part of aircraft design and the behavior of structural components of aircraft systems needs to be evaluated undergoing time varying loads. This is done by creating Finite Elements (FE) models and carrying out dynamic analysis in the frequency or time domain. The first approach is faster but only can be used in linear theory, namely when all materials involved in the structural model have linear constitutive equations. But sometimes FE models of aircraft structures contain a small number of non-linearities usually localized in the connection points between the assembled components. In this paper an approach that allows to perform frequency analysis in structural models having several nonlinear springs is presented and its performance is compared with the results provided by time domain analysis methods. An application example that represents a quite realistic assembly between two fuselage sections and a real aircraft connection system are presented.