A new microcontrolled structural health monitoring system based on the electromechanical impedance principle

Abstract

This article presents a new method to detect damage in structures based on the electromechanical impedance principle. The system follows the variations in the output voltage of piezoelectric transducers and does not compute the impedance itself. The proposed system is portable, autonomous, versatile, and could efficiently replace commercial instruments in different structural health monitoring applications. The identification of damage is performed by simply comparing the variations of root mean square voltage from response signals of piezoelectric transducers, such as lead zirconate titanate patches bonded to the structure, obtained for different frequencies of the excitation signal. The proposed system is not limited by the sampling rate of analog-to-digital converters, dispenses Fourier transform algorithms, and does not require a computer for processing, operating autonomously. A low-cost prototype based on microcontroller and digital synthesizer was built, and experiments were carried out on an aluminum structure and excellent results have been obtained.

Modelling and Simulation of Impedance-Based Damage Monitoring of Structures

“…The electromechanical impedance principle was the basis for a new method of damage detection in structures presented by Cortez et al [6]. The system did not compute the impedance but rather followed variations in piezoelectric transducer's voltage output.…”

Design and implementation of wireless sensor networks for impedance-based structural health monitoring using ZigBee and Global System for Mobile Communications

“…This methodology has been confirmed experimentally, and the results indicate that it is possible to develop a simple SHM system based on EMI, only monitoring the RMS voltage of the PZT transducer in an appropriate frequency range. This result was recently analyzed and discussed by Cortez et al (2013).…”

“…Details of these hardware designs have been described by Cortez et al (2013). This section describes only the hardware design of computational core and wireless transceiver ZigBee module.…”

“…The PZT is excited by sinusoidal signals in an appropriate frequency range, and the system is not limited by the sample rate of the ADC (Cortez et al, 2013).…”

“…Each sensor node is a portable and autonomous SHM core based on microcontroller, digital synthesizer, and wireless transceiver ZigBee. Damage detection is performed by comparing RMS variations computed from response signals of piezoelectric transducers, such as PZT patches bonded to the structure, without computing the EMI (Cortez et al, 2013).…”