Experimental Detection and Quantification of Structural Nonlinearity Using Homogeneity and Hilbert Transform Methods

Knud Abildgaard Kragh, Jon Juel Thomsen, Dmitri Tcherniak

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Abstract

All real structures are inherently nonlinear. Whether a structure exhibits linear or nonlinear behavior, depends mainly on the excitation level. So far no unequivocal framework for experimental detection, localization, and characterization of structural nonlinearities from dynamic measurements exists. The present study suggests a framework for the detection of structural nonlinearities. Two methods for detection are compared, the homogeneity method and a Hilbert transform based method. Based on these two methods, a nonlinearity index is suggested. Through simulations and laboratory experiments it is demonstrated, for a simple but representative nonlinear structure, that both detection methods are able to detect even weak nonlinearities, and that the nonlinearity index provides a sensitive and robust measure of nonlinearity. For a range of input force amplitudes, it is shown that it is possible to estimate a systems linear and nonlinear regimes in terms of input amplitude, and asses the strength of the nonlinearity.
Original languageEnglish
Title of host publicationProceedings of ISMA2010-USD2010
Publication date2010
Publication statusPublished - 2010
EventISMA2010 : International conference on Noise and Vibration Engineering - Leuven, Belgium
Duration: 1 Jan 2010 → …

Conference

ConferenceISMA2010 : International conference on Noise and Vibration Engineering
CityLeuven, Belgium
Period01/01/2010 → …

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