Aktivni monitoring i detekcija oštećenja armirano betonskih konstrukcija primenom piezoelektričnih agregata
This dissertation is focused on the development of methods for the damage detection and localization in concrete structures. This research is an attempt to meet the requirements of monitoring and non-destructive testing and assessment (NDI / P) of structures, as well as to reduce the current shortcoming in methods for monitoring the condition of concrete structures. The research gives numerical procedures for modeling the damage detection in linear reinforced concrete (RC) elements, starting from the model of piezoelectric smart aggregates (PZT PA) and further to the models of wave propagation. Verification of numerical models based on experimentally obtained results was performed, as well as parametric analysis of the change in RMSD (root mean square deviations) of the damage index in relation to individual parameters. For plate concrete elements, detection was performed using the existing two-dimensional damage index based on numerical simulations. For the damage localization, a hybrid method based on energy approach, time of propagation of the incoming wave from the actuator to the sensor as well as discrete wavelet signal transformation has been developed. A hybrid approach has been developed for the general shape of the concrete element, arbitrary number and position of PZT actuators / sensors, and arbitrary shape and position of damage. The mentioned hybrid approach was verified through experimental and numerical research on models with one and two damaged points. For 3D damage detection in concrete structres, a three-dimensional (3D) damage index based on a one-dimensional (1D) RMSD damage index has been developed. The 3D damage index was calculated for different damage cases, based on the results obtained by numerical simulations. A hybrid method developed for plate elements has been extended to 3D damage localization. A hybrid method for spatial damage localization was verified on parallelepiped samples/models by comparing experimental and numerical results. The obtained results indicate that the methods for damage detection and localization are very efficient for linear and plate concrete elements, while in the case of 3D concrete structures, further elaboration of the presented method is necessary. All methods presented in the doctoral dissertation have been numerically tested and some have been experimentally verified. The main aim of the development of the aforementioned methods for the damage detection and localization is to enable the use of PZT actuators/sensors for structural health monitoring of concrete structures over time.
Biografija autora: list 201,Bibliografija: listovi 169-182. Datum odbrane: 23.11.2022. Steel and Timber structures
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