Electro-mechanical impedance (EMI)-based incipient crack monitoring and critical crack identification of beam structures
Lim, Yee Yan
Soh, Chee Kiong
Date of Issue2014
School of Civil and Environmental Engineering
Fatigue-induced damage is often progressive and gradual in nature. Fatigue is often deteriorated by corrosion in ageing structures, creating maintenance problems, and even causing catastrophic failure. This ushers the development of structural health monitoring (SHM) and nondestructive evaluation (NDE) systems. Recent advent of smart materials applicable in SHM alleviates the shortcomings of the conventional techniques. Autonomous, real-time, remote monitoring becomes possible with the use of smart piezoelectric transducers. For instance, the electro-mechanical impedance (EMI) technique, employing piezoelectric transducers as collocated actuators and sensors, is known for its ability in damage detection and characterization. This article presents a series of lab-scale experimental tests and analysis to investigate the feasibility of fatigue crack detection and characterization employing the EMI technique. This study extends the work by Lim and Soh  to incorporate the phases involving crack initiation and critical crack. It is suggested that the EMI technique is effective in characterizing fatigue induced cracking, even in its incipient stage. Micro-crack invisible to the naked eyes can be detected by the technique especially when employing the higher frequency range of 100–200 kHz. A quick and handy qualitative-based critical crack identification method is also suggested by visually inspecting the admittance frequency spectrum.
DRNTU::Engineering::Civil engineering::Construction technology
Research in nondestructive evaluation
© 2014 American Society for Nondestructive Testing. This paper was published in Research in Nondestructive Evaluation and is made available as an electronic reprint (preprint) with permission of American Society for Nondestructive Testing. The paper can be found at the following official DOI: [http://dx.doi.org/10.1080/09349847.2013.848311]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law."