Ambient vibration modal identification, also known as Operational Modal Analysis, aims to identify the modal properties of a structure based on vibration data collected when the structure is under its operating conditions, i.e., no initial excitation or known artificial excitation. This procedure for testing and/or monitoring historic buildings, is particularly attractive for civil engineers concerned with the safety of complex historic structures. However, since the external force is not recorded, the identification methods have to be more sophisticated and based on stochastic mechanics. In this context, this contribution will introduce an innovative ambient identification method based on applying the Hilbert Transform, to obtain the analytical representation of the system response in terms of the correlation function. In particular, it is worth stressing that the analytical signal is a complex representation of a time domain signal: the real part is the time domain signal itself, while the imaginary part is its Hilbert transform. A 3DOF numerical example will be presented to show the accuracy of the proposed procedure, and comparisons with data from other methods assess the reliability of the approach. Finally, the identification method will be extended to the real case study of the Chiaramonte Palace, a historic building located in Palermo and known as “Steri”.

中文翻译：

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一种新的环境振动数据识别程序

环境振动模态识别，也称为运行模态分析，旨在根据结构在其运行条件下（即没有初始激励或已知人工激励）时收集的振动数据来识别结构的模态特性。这种用于测试和/或监控历史建筑的程序对于关注复杂历史建筑安全的土木工程师特别有吸引力。但是，由于没有记录外力，因此识别方法必须更加复杂并基于随机力学。在此背景下，本文将介绍一种基于应用希尔伯特变换的创新环境识别方法，以获得系统响应在相关函数方面的解析表示。特别是，值得强调的是，解析信号是时域信号的复数表示：实部是时域信号本身，而虚部是其希尔伯特变换。将提供一个 3DOF 数值示例来显示所提出程序的准确性，并与其他方法的数据进行比较以评估该方法的可靠性。最后，识别方法将扩展到 Chiaramonte Palace 的真实案例研究，这是一座位于巴勒莫的历史建筑，被称为“Steri”。并与来自其他方法的数据进行比较评估该方法的可靠性。最后，识别方法将扩展到 Chiaramonte Palace 的真实案例研究，这是一座位于巴勒莫的历史建筑，被称为“Steri”。并与来自其他方法的数据进行比较评估该方法的可靠性。最后，识别方法将扩展到 Chiaramonte Palace 的真实案例研究，这是一座位于巴勒莫的历史建筑，被称为“Steri”。