Admittance Measurements for Structural Health Monitoring in Metal Plates

Structural Health Monitoring (SHM) in civil and mechanical engineering fields plays a vital role in the current scenario. Electro Mechanical Impedance technique (EMI) is the most common method used in structural health monitoring. The impedance chip is small and low cost device used for structural health monitoring. In this paper, experiments are performed on a metal plate. Holes are induced in the metal plate, and metal bolts are used to fix the metal sheet. Piezo sensors (lead zirconate titanate patches) are used to detect the damage. Sensors are bonded to the metal plates. New metal bolt and corroded bolt are used to fix the metal sheet. The outputs are measured by using impedance chip. The bolts are removed, and the corresponding output is also measured using impedance chip. Comparison of conductance, admittance and susceptance are performed with the usage of new bolt, corroded bolt and removal of bolt. The results confirm the presence of damage in using the corroded bolt and as well as in the removal of bolt.