Modal testing of nonlinear vibrating structures based on nonlinear normal modes: Experimental demonstration
Modal testing of nonlinear vibrating structures based on nonlinear normal modes: Experimental demonstration
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DOI：
10.1016/j.ymssp.2010.11.006
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发表时间：
2011-05-01
影响因子：
8.4
通讯作者：
Golinval, J. C.
中科院分区：
文献类型：
--
作者：
Peeters, M.;Kerschen, G.;Golinval, J. C.
考虑到非线性是工程结构中经常出现的现象，线性试验模态分析(EMA)在这方面的作用有限，本文试图通过从非线性力学系统的时间序列中提取非线性简正模式(NNM)来发展非线性EMA。基于相位共振测试的非线性扩展，所提出的方法在实验期间激励结构以隔离单个NNM。利用不变性原理，可以利用时频分析从得到的自由衰减响应中提取该非线性模式的能量依赖关系(即NNM模式曲线及其振荡频率)。本文致力于这一过程的实验论证和稳健性。为此，考虑了一个具有几何非线性的实验悬臂梁，并评估了所提出的方法从测量响应中提取其网络模型的能力。(C)2010爱思唯尔有限公司。保留所有权利。
Realizing that nonlinearity is a frequent occurrence in engineering structures and that linear experimental modal analysis (EMA) is of limited usefulness in this context, the present paper is an attempt to develop nonlinear EMA by targeting the extraction of nonlinear normal modes (NNMs) from time series of nonlinear mechanical systems. Based on a nonlinear extension of phase resonance testing, the proposed methodology excites the structure to isolate a single NNM during the experiments. Thanks to the invariance principle, the energy dependence of that nonlinear mode (i.e., the NNM modal curves and their oscillation frequencies) can be extracted from the resulting free decay response using time-frequency analysis. This paper is devoted to the experimental demonstration and robustness of this procedure. To this end, an experimental cantilever beam with a geometrical nonlinearity is considered, and the ability of the proposed methodology to extract its NNMs from the measured responses is assessed. (C) 2010 Elsevier Ltd. All rights reserved.