17 May 2005 Identification of nonlinear normal modes of structures using the empirical mode decomposition method
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The Empirical Mode Decomposition (EMD), which combines with the Hilbert transform (HT), has been used successfully to identify the dynamic characteristics of linear multi-degree-of-freedom structures. In this study, the EMD method is applied to the identification of nonlinear normal modes (NNMs) of nonlinear multi-degree-of-freedom (MDOF) structures. It is shown that the intrinsic mode functions (IMFs), which are obtained by applying the EMD method to the structural response, agree quite well with the nonlinear modal responses obtained from the invariant manifold approach. A two-degree-of-freedom building model with nonlinear stiffness is used for illustration. The EMD method is applied to decompose the measured response of the building model. The resulting IMFs are compared with the corresponding nonlinear modal responses, including their instantaneous frequencies and time-dependent amplitudes from the HT method. The comparison indicates that the resulting IMFs from the EMD method can reveal the nonlinear modal responses. It is seen that this EMD-based technique is fairly accurate to determine the nonlinear stiffness characteristics of the building model. The result suggests that the IMFs can be used to determine the physical dynamic properties of nonlinear structures.
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Chun-Wing Poon, Chun-Wing Poon, Chih-Chen Chang, Chih-Chen Chang, "Identification of nonlinear normal modes of structures using the empirical mode decomposition method", Proc. SPIE 5765, Smart Structures and Materials 2005: Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, (17 May 2005); doi: 10.1117/12.599237; https://doi.org/10.1117/12.599237

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