“…In the past decade, the majority of research works in the field of structural health monitoring (SHM) have been thus far focused on the development of damage detection and localization algorithms using various approaches such as laser Doppler velocimetry, fiber Bragg grating, piezoelectric wafer active sensors (PWASs), piezoelectric paint, and intelligent resistive coating materials (Bai et al, 2015; Barazanchy et al (2014); Cao and Ouyang, 2016; Chinde et al, 2016; Fan and Qiao, 2011; Feng et al, 2014; Giurgiutiu, 2014; Kaloop and Hu, 2015; Kharroub et al, 2015; Kumar and Reddy, 2016; Peters and Webb, 2015; Statham, 2011; Wang et al (2016); Witos, 2008; Xu and Giurgiutiu, 2005, 2006; Yang and Fritzen, 2011a, 2011b, 2012) Zhao et al (2007). SHM based on electromechanical impedance (EMI) of piezoelectric transducers was first reported by Giurgiutiu and Zagrai (2000) to compare the impedance/admittance frequency spectrum of pristine and damaged specimens, particularly at an ultrasonic frequency range of 100 Hz–12 MHz.…”