Noncontact Operational Modal Analysis of Structural Members by Laser Doppler Vibrometer
Noncontact Operational Modal Analysis of Structural Members by Laser Doppler Vibrometer
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DOI：
10.1111/j.1467-8667.2008.00585.x
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发表时间：
2009-05
期刊：
影响因子：
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通讯作者：
D. Siringoringo;Y. Fujino
中科院分区：
文献类型：
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作者：
D. Siringoringo;Y. Fujino
摘要：开发了一套利用环境振动和双激光多普勒测振仪（LDV）对结构构件进行非接触工作模态分析的系统。该系统采用自然激励技术（NExT）从激光信号中产生互相关函数，并采用特征系统实现算法（ERA）识别结构构件的模态参数。为了便于同时模态识别，提出了时间同步技术和从激光信号的环境响应构造互相关函数。通过实验验证了所提出的系统的性能，评估在不同的测量条件下的识别结果的一致性和准确性。本文所做的工作是对前人研究的扩展，提出了一种基于模态的LDV损伤检测方法。在本研究中，LDV的组合动力系统的结构参数识别的应用。一个模型，表示连接属性的附加刚度和阻尼的开发，其重要性的结构损伤检测进行了讨论。研究表明，通过跟踪模态相位差和量化附加刚度和阻尼，可以检测出钢连接中是否存在模拟损伤。
Abstract: A system that uses ambient vibration and two laser Doppler vibrometer (LDV) is developed for noncontact operational modal analysis of structural members. The system employs natural excitation technique (NExT) to generate the cross‐correlation functions from laser signals, and the eigensystem realization algorithm (ERA) to identify modal parameters of structural members. To facilitate simultaneous modal identification, time‐synchronization technique and construction of cross‐correlation functions from ambient response of laser signals are proposed. Performance of the proposed system is verified experimentally by evaluating the consistency and accuracy of identification results in different measurement conditions. The work presented here is an extension of the previous study, where a modal‐based damage detection method using LDV was formulated. In the present study, application of LDV for structural parameters identification of a combined dynamical system is proposed. A model that represents the connection properties in terms of additional stiffness and damping is developed, and its importance for structural damage detection is discussed. The study shows that the presence of simulated damage in a steel connection can be detected by tracking the modal phase difference and by quantifying the additional stiffness and damping.