Cosoli Gloria, Martarelli Milena, Mobili Alessandra, Tittarelli Francesca, Revel Gian Marco
Department of Industrial Engineering and Mathematical Sciences, Marche Polytechnic University, 60131 Ancona, Italy.
Department of Materials, Environmental Sciences and Urban Planning, Marche Polytechnic University, 60131 Ancona, Italy.
Sensors (Basel). 2023 Nov 20;23(22):9292. doi: 10.3390/s23229292.
Modal analysis is an effective tool in the context of Structural Health Monitoring (SHM) since the dynamic characteristics of cement-based structures reflect the structural health status of the material itself. The authors consider increasing level load tests on concrete beams and propose a methodology for damage identification relying on the computation of modal curvatures combined with continuous wavelet transform (CWT) to highlight damage-related changes. Unlike most literature studies, in the present work, no numerical models of the undamaged structure were exploited. Moreover, the authors defined synthetic damage indices depicting the status of a structure. The results show that the I mode shape is the most sensitive to damages; indeed, considering this mode, damages cause a decrease of natural vibration frequency (up to approximately -67%), an increase of loss factor (up to approximately fivefold), and changes in the mode shapes morphology (a cuspid appears). The proposed damage indices are promising, even if the level of damage is not clearly distinguishable, probably because tests were performed after the load removal. Further investigations are needed to scale the methodology to in-field applications.
模态分析在结构健康监测（SHM）领域是一种有效的工具，因为水泥基结构的动态特性反映了材料本身的结构健康状况。作者考虑对混凝土梁进行递增水平荷载试验，并提出一种基于模态曲率计算结合连续小波变换（CWT）来突出损伤相关变化的损伤识别方法。与大多数文献研究不同，在本研究中，未使用未受损结构的数值模型。此外，作者定义了描述结构状态的综合损伤指标。结果表明，第一阶振型对损伤最敏感；事实上，考虑该振型时，损伤会导致固有振动频率降低（高达约-67%）、损耗因子增加（高达约五倍）以及振型形态发生变化（出现一个尖点）。所提出的损伤指标很有前景，尽管损伤程度不太能清晰区分，这可能是因为试验是在卸载后进行的。需要进一步研究以将该方法扩展到现场应用。
