Health monitoring of thin plate structure using electromechanical impedance technique
Tan, Tee Yong
Date of Issue2016-05-18
School of Civil and Environmental Engineering
Structural health monitoring (SHM) has become a vital tool to help engineers improve and maintain the overall safety of the structures. SHM combines different types of sensing technologies to allow engineers capture, log and analyze read time data. There are various types of sensors available in the market. In particular, piezoelectric (PZT) transducer is a popular sensor use in the industry. The PZT sensor is cost effective, small in size and is able to be installed in a confined area of the structure and it is a non-destructive method. In this project, nine PZT transducers patch and nine strain gauges were surface bonded to a thin plate aluminum specimen in an attempt to study the changes in the structure behavior when displacement and progressive damage were applied to the specimen. The admittance signatures were obtained from the impedance analyzer and the strain gauge data were obtained from the data logger. The experimental results were then analyzed using experimental analysis methods and statistical method to detect changes in the peak frequency values and also to observe any consistent trend of the conductance signatures when the displacement and the hole diameter of the aluminum thin plate specimen increased. From the experimental results, it proves that the PZT transducer was useful in detecting damage in the aluminum specimen. The strain gauge was more capable of detecting displacement and strain of the aluminum specimen. Numerical modeling of the aluminum thin plate specimen was being carried out using the ANSYS program. The result of the numerical modeling shows a similar trend compared with the experimental result. The result of the numerical modeling shows that the force reactions for the displacements were very small and the deformation was too little. The PZT transducer was capable of detecting damage in the aluminum specimen, but was not able to detect displacements that were too small.
Final Year Project (FYP)
Nanyang Technological University