Papers by Author: Gyuhae Park

Abstract: In this study, a hybrid health monitoring technique that combines wireless sensing and embedded monitoring algorithms is proposed to realize the diagnosis of damage in PSC girder bridges. Firstly, a hybrid damage monitoring system that can alarm damage occurrence and classify damage-types is designed for PSC girder bridges. Secondly, smart sensor nodes that have wireless, stand-alone, sensing and monitoring capacities of acceleration and impedance are developed for hybrid health monitoring of the structures. Finally, the performance of the smart sensor nodes is evaluated using a laboratory-scale PSC girder bridge model for which acceleration and impedance signals were measured for prestress-loss and stiffness-loss cases.

Abstract: A new model of impedance-based structural health monitoring (SHM) using the spectral element method (SEM) and electric circuit analysis has been developed. This model provides additional information for more accurately identifying and locating damage and in designing the SHM system. Complex functions of the SHM system such as estimation of remaining life are also made possible with the use of the model. The circuit analysis can be applied to any type of structural model. However, since impedance-based SHM relies on high frequency excitation of the structure using piezoelectric patches, finite element modeling may not be applicable and instead the spectral element method (SEM) is used. SEM more accurately models higher frequency vibrations since the mass is modeled “exactly” and incorporates higher order models more easily. Model and experimental results are presented for damaged and undamaged specimens.