Kim Byungmo, Min Cheonhong, Kim Hyungwoo, Cho Sugil, Oh Jaewon, Ha Seung-Hyun, Yi Jin-Hak
Department of Convergence Study on the Ocean Science and Technology, Ocean Science and Technology School of Korea Maritime and Ocean University, Busan 49112, Korea.
Offshore Industries R&BD Center, Korea Research Institute of Ships & Ocean Engineering (KRISO), Geoje 53201, Korea.
Sensors (Basel). 2019 Jul 10;19(14):3047. doi: 10.3390/s19143047.
There is a large risk of damage, triggered by harsh ocean environments, associated with offshore structures, so structural health monitoring plays an important role in preventing the occurrence of critical and global structural failure from such damage. However, obstacles, such as applicability in the field and increasing calculation costs with increasing structural complexity, remain for real-time structure monitoring offshore. Therefore, this study proposes the comparison of cosine similarity with sensor data to overcome such challenges. As the comparison target, this method uses the rate of changes of natural frequencies before and after the occurrence of various damage scenarios, including not only single but multiple damages, which are organized by the experiment technique design. The comparison method alerts to the occurrence of damage using a normalized warning index, which enables workers to manage the risk of damage. By comparison, moreover, the case most similar with the current status is directly figured out without any additional analysis between monitoring and damage identification, which renders the damage identification process simpler. Plus, the averaged rate of errors in detection is suggested to evaluate the damage level more precisely, if needed. Therefore, this method contributes to the application of real-time structural health monitoring for offshore structures by providing an approach to improve the usability of the proposed technique.
由于恶劣的海洋环境，海上结构面临着巨大的损坏风险，因此结构健康监测在防止此类损坏导致关键和整体结构失效方面发挥着重要作用。然而，对于海上实时结构监测而言，仍存在一些障碍，例如在现场的适用性以及随着结构复杂性增加而不断上升的计算成本。因此，本研究提出将余弦相似度与传感器数据进行比较，以克服这些挑战。作为比较对象，该方法使用各种损坏情况（包括单一损坏和多重损坏）发生前后固有频率的变化率，这些损坏情况是通过实验技术设计来组织的。该比较方法使用归一化警告指数对损坏的发生发出警报，使工作人员能够管理损坏风险。此外，通过比较，无需在监测和损坏识别之间进行任何额外分析，就能直接找出与当前状态最相似的情况，从而使损坏识别过程更加简单。另外，如果需要，建议使用平均检测误差率来更精确地评估损坏程度。因此，该方法通过提供一种提高所提技术可用性的方法，有助于海上结构实时结构健康监测的应用。
