Identification of modal parameters from transmissibility measurements
Identification of modal parameters from transmissibility measurements
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DOI：
10.1016/j.jsv.2007.12.022
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发表时间：
2008-07-08
影响因子：
4.7
通讯作者：
Guillaume, Patrick
中科院分区：
文献类型：
--
作者：
Devriendt, Christof;Guillaume, Patrick
众所周知，结构的线性动力学行为可以通过对作用于结构的力[输入]与其产生的结构振动响应[输出]之间的关系进行建模来研究。对于工业结构，在其真实的运行条件下，通常很难（或不可能）通过实验测量激励。由于这个原因，系统识别技术已经开发出来，只在响应数据的基础上工作。然而，当前仅输出技术在应用于一些实际情况时具有严重的局限性。当前OMA技术的一个限制性约束是对操作中的系统的未测量激励必须是白噪声序列。然而，在实践中，在操作中观察到的结构振动并不总是被认为是纯粹的白噪声激励。目前的技术可能会遇到困难，以正确地识别模态参数。本文介绍了一种新的OMA方法来识别模态参数的输出只有传输率测量。该方法不对系统的激励性质作任何假设。通常，从传输率测量识别的极点与系统的极点不对应。然而，通过结合在不同的负载条件下的传输率测量，本文表明，模态参数可以识别。本文对悬臂梁进行了数值实验。对基于传递率测量的传统输入-输出模态分析和新的仅输出模态分析的结果进行了比较。(C)2007爱思唯尔有限公司版权所有。
It is a well-known fact that linear dynamic behavior of structures can be studied by modeling the relation between force(s) [input(s)], acting on a structure, and their resulting structural vibration response(s) [output(s)]. For industrial structures, in their real in-operation conditions, it often becomes hard (or impossible) to experimentally measure the excitation. For this reason system identification techniques have been developed that work on a basis of response data only. However, current output only techniques have serious limitations when applied to some practical cases. One limiting constraint of the current OMA techniques is that the non-measured excitations to the system in operation must be white-noise sequences. In practice however, structural vibrations observed in operation cannot always be considered as pure white-noise excitation. Current techniques may encounter difficulties to correctly identify the modal parameters. In this paper a new OMA approach to identify modal parameters from output-only transmissibility measurements is introduced. This method does not make any assumption about the nature of the excitations to the system. In general, the poles that are identified from transmissibility measurements do not correspond with the system's poles. However, by combining transmissibility measurements under different loading conditions, it is shown in this paper that modal parameters can be identified. In this contribution a numerical experiment on a cantilever beam was conducted. A comparison was made between the results of a classic input-output and the new output-only modal analysis based on transmissibility measurements. (C) 2007 Elsevier Ltd. All rights reserved.