Sliding window POD analysis of vibrating structures. Application to nonlinear forced structure under axial flow

In this paper, a multivariate data analysis method combining the Proper Orthogonal Decomposition (POD) and a time-frequency analysis (TEA) is presented. The POD method is a tool adapted to the study of multi-degrees of freedom systems, which can give some insight of the behavior of complex nonlinear systems, whereas TEA is suitable for scalar signal with multi-frequency components. The method presented here is of principal interest in the case of swept-sine excitation of complex multi-DOF systems. It will be first applied to a synthetic signal, then mechanical simulations and finally experimental results. (authors)