Soutenance de thèse de doctorat
M. TA Duc-Tuan soutiendra sa thèse de doctorat portant sur le "suivi de santé structurale basé sur l’identification modale opérationnelle". La soutenance aura lieu le jeudi 13 octobre 2022 à 14h00, à l'UFRST, 40 Rue du Pelvoux, Evry
Les travaux de M. TA Duc-Tuan sont dirigés par M. LE Thien-Phu et M. BURMAN Michael
Structural health monitoring (SHM) is primordial for safe use of engineering structures and is essential for their sustainable development. Among existing methods of SHM, vibration-based methods are the most commonly used. This approach is particularly suitable for real structures when operational modal analysis is applied as it offers several advantages: low cost, real boundary conditions, and continuous monitoring without stopping normal service of structures. However, it has some main obstacles: (i) the uncertainty due to unmeasured and uncontrolled operational excitations; (ii) underdetermined problems for real systems, when the number of measured responses is less than that of active modes; (iii) the relationship between the damage in terms of change in mass and/or stiffness and the change in modal parameters, is not straightforward, and it often goes through finite element update steps resulting in computational burden; (iv) the presence of several damages in a structure is not obvious to detect and more challenging for multiple damage detection procedures.
In an attempt to offer solutions to the above problems, this dissertation developed proposals on four topics, which are summarized as follows:
(i) Improvement of the existing modal analysis technique based on the PARAllel FACtor (PARAFAC) decomposition in time domain that can effectively handle underdetermined cases and cases with the presence of harmonic excitations;
(ii) Development of a novel method for modal analysis based on PARAFAC decomposition in frequency domain. This method allows solving more complex cases in modal analysis such as complex modes, closely spaced modes;
(iii) Proposal of an efficient method for the rapid detection and quantification of a local change in the mass and/or stiffness of like-beam structures;
(iv) Extension for multiple damage detection procedure based on the comparison of frequency shifts obtained from the analytical expression established in the previous section with measured ones using Bayesian inference.
All the above contributions have been validated by numerical simulations and experimental laboratory tests.