An experimental study of the feasibility of phase-based video magnification for damage detection and localisation in operational deflection shapes
An experimental study of the feasibility of phase-based video magnification for damage detection and localisation in operational deflection shapes
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DOI：
10.1111/str.12336
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发表时间：
2020-01-08
期刊：
影响因子：
2.1
通讯作者：
Surace, C.
中科院分区：
文献类型：
--
作者：
Civera, M.;Fragonara, L. Zanotti;Surace, C.
来自高速、高清晰度视频记录的光学测量可用于定义结构的全场动态。通过比较受损和未受损元件的动态响应，可以进行结构健康监测，类似于安装传感器。与提供逐点测量和有限数量的输出通道的物理传感器不同，高质量的视频记录允许非常空间密集的信息。此外，视频采集是一种非接触技术。这保证了动态行为中的任何异常都可以更容易地与损坏相关联，而不是由于安装的传感器而增加的质量或刚度。然而，在现实生活中的场景中，由于环境输入的振动往往是如此之小，它们是无法区分的测量噪声，如果传统的基于图像的技术被应用。为了提高低幅度测量中的信噪比，最近提出了基于相位的运动放大。本研究旨在表明，基于模型的结构健康监测可以进行基于相位的运动放大处理的模态数据和时间历程，而未放大的振动将太小，被成功利用。所有的试验都是在不同损伤尺寸和角度的多损伤箱梁上进行的。
Optical measurements from high-speed, high-definition video recordings can be used to define the full-field dynamics of a structure. By comparing the dynamic responses resulting from both damaged and undamaged elements, structural health monitoring can be carried out, similarly as with mounted transducers. Unlike the physical sensors, which provide point-wise measurements and a limited number of output channels, high-quality video recording allows very spatially dense information. Moreover, video acquisition is a noncontact technique. This guarantees that any anomaly in the dynamic behaviour can be more easily correlated to damage and not to added mass or stiffness due to the installed sensors. However, in real-life scenarios, the vibrations due to environmental input are often so small that they are indistinguishable from measurement noise if conventional image-based techniques are applied. In order to improve the signal-to-noise ratio in low-amplitude measurements, phase-based motion magnification has been recently proposed. This study intends to show that model-based structural health monitoring can be performed on modal data and time histories processed with phase-based motion magnification, whereas unamplified vibrations would be too small for being successfully exploited. All the experiments were performed on a multidamaged box beam with different damage sizes and angles.