Development of Structural Health Monitoring System for Structures in Operational Conditions
Deniss Mironovs

03.11.2023. 14:00, Ķīpsalas ielā 6A, Rīga, 342. auditorijā

Aleksejs Mironovs, Andris Čate

Līga Gaile, Andrzej Katunin, Miroslaw Wesolowski

The present thesis is devoted to application of state-of-the-art structural health monitoring techniques, aiming to development of functional structural health monitoring system for objects in operation, as well as development of methodologies, aiding in damage recognition, data processing and analysis. The first part of the presented thesis covers literature review of topic connected to structural health monitoring and operational modal analysis in particular as an established vibration-based technique for SHM. Apart from methodological aspects, technological ones are discussed. Thesis offers to substitute commonly used accelerometers with PVDF piezo film deformation sensors. Theoretical background and experimental validation shows, that the use of deformation instead of acceleration signals allows to perform modal analysis of a structure with the same quality. Harmonics extraction algorithm from vibrational responses of a structure with periodical excitation component was proposed. In practical implementations the algorithm utilizes tacho signal from a rotating shaft, which keeps the phase variance for each rotation. This is later used to enhance the signal of structural response and obtain a significantly emphasized periodical component. This component is subtracted from the response in frequency domain and inverse Fourier transform gives a filtered structural response, with significantly reduced presence of harmonics. A road map for developing an SHM system is formulated in this thesis. This road map serves as a step-by-step instruction for assembling and using SHM system for fixed and rotating structures like helicopter or wind turbine blades. As part of the road map a concept of modal passport is introduced, which serves as a framework for storing and analysis modal data. Two damage detection algorithms are introduced – Modal Field Comparison method and Modal Parameter Variation. These methods are useful tools for detecting damage in measured structures. The last Section of the thesis shows case studies, where the introduced concepts are tested and validated during experiments on several structures. These structures are – aluminium beam, wind turbine laboratory model, airport radar tower and small helicopter composite blades.

operational modal analysis, structural health monitoring, damage identification

Mironovs, Deniss. Development of Structural Health Monitoring System for Structures in Operational Conditions. PhD Thesis. Rīga: [RTU], 2023. 113 p.

Publication language
English (en)
The Scientific Library of the Riga Technical University.
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