Lin Tzu-Kang, Lee Dong-You
Department of Civil Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan.
Entropy (Basel). 2020 Dec 31;23(1):60. doi: 10.3390/e23010060.
This study proposesd a novel, entropy-based structural health monitoring (SHM) system for measuring microvibration signals generated by actual buildings. A structural health diagnosis interface was established for demonstration purposes. To enhance the reliability and accuracy of entropy evaluation at various scales, composite multiscale cross-sample entropy (CMSCE) was adopted to increase the number of coarse-grained time series. The degree of similarity and asynchrony between ambient vibration signals measured on adjacent floors was used as an in-dicator for structural health assessment. A residential building that has been monitored since 1994 was selected for long-term monitoring. The accumulated database, including both the earthquake and ambient vibrations in each seismic event, provided the possibility to evaluate the practicability of the CMSCE-based method. Entropy curves obtained for each of the years, as well as the stable trend of the corresponding damage index (DI) graphs, demonstrated the relia-bility of the proposed SHM system. Moreover, two large earthquake events that occurred near the monitoring site were analyzed. The results revealed that the entropy values may have been slightly increased after the earthquakes. Positive DI values were obtained for higher floors, which could provide an early warning of structural instability. The proposed SHM system is highly stable and practical.
本研究提出了一种新颖的、基于熵的结构健康监测（SHM）系统，用于测量实际建筑物产生的微振动信号。为了演示目的，建立了一个结构健康诊断界面。为提高不同尺度下熵评估的可靠性和准确性，采用复合多尺度交叉样本熵（CMSCE）来增加粗粒化时间序列的数量。将相邻楼层测量的环境振动信号之间的相似程度和异步程度用作结构健康评估的指标。选择了一座自1994年以来一直被监测的住宅楼进行长期监测。积累的数据库，包括每次地震事件中的地震振动和环境振动，为评估基于CMSCE的方法的实用性提供了可能性。每年获得的熵曲线以及相应损伤指数（DI）图的稳定趋势，证明了所提出的SHM系统的可靠性。此外，还分析了监测地点附近发生的两次大地震事件。结果表明，地震后熵值可能略有增加。较高楼层获得了正的DI值，这可以为结构不稳定提供早期预警。所提出的SHM系统高度稳定且实用。
