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Smart Structures and Systems
  Volume 19, Number 4, April 2017 , pages 361-369
DOI: https://doi.org/10.12989/sss.2017.19.4.361
 


Crack detection in rectangular plate by electromechanical impedance method: modeling and experiment
Mehdi Rajabi, Mahnaz Shamshirsaz and Mahyar Naraghi

 
Abstract
    Electromechanical impedance method as an efficient tool in Structural Health Monitoring (SHM) utilizes the electromechanical impedance of piezoelectric materials which is directly related to the mechanical impedance of the host structure and will be affected by damages. In this paper, electromechanical impedance of piezoelectric patches attached to simply support rectangular plate is determined theoretically and experimentally in order to detect damage. A pairs of piezoelectric wafer active sensor (PWAS) patches are used on top and bottom of an aluminum plate to generate pure bending. The analytical model and experiments are carried out both for undamaged and damaged plates. To validate theoretical models, the electromechanical impedances of PWAS for undamaged and damaged plate using theoretical models are compared with those obtained experimentally. Both theoretical and experimental results demonstrate that by crack generation and intensifying this crack, natural frequency of structure decreases. Finally, in order to evaluate damage severity, damage metrics such as Root Mean Square Deviation (RMSD), Mean Absolute Percentage Deviation (MAPD), and Correlation Coefficient Deviation (CCD) are used based on experimental results. The results show that generation of crack and crack depth increasing can be detectable by CCD.
 
Key Words
    electromechanical impedance method; Structural Health Monitoring; damage index; crack intensity; thin plate; modeling; experiments
 
Address
Mehdi Rajabi, Mahyar Naraghi: Department of Mechanical Engineering, Amirkabir University of Technology, Tehran, Iran

Mehdi Rajabi, Mahnaz Shamshirsaz: New Technologies Research Center, Amirkabir University of Technology, Tehran, Iran
 

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