Wireless Structural Health Monitoring and Early-Stage Damage Detection Using Piezoelectric Impedance Sensors

This paper presents recent achievements of novel wireless structural health monitoring (SHM) techniques and early-stage damage diagnosis for critical members of civil, mechanical and aerospace structures using piezoelectric impedance sensors. The basic concept of the electro-mechanical impedance-based SHM technique is to use simultaneously both high-frequency structural excitations and responses employing piezoelectric sensors to monitor the local area of a structure for changes in structural impedance that would indicate imminent damage. To obtain an electro-mechanical impedance data at the piezoelectric sensors attached to a host structure, a wireless impedance sensor node that consists of a miniaturized impedance-measuring chip, a microprocessor, and a radio frequency (RF) telemetry is utilized. Furthermore, the autoregressive features extracted from a frequency-domain Auto-Regressive model with eXogenous (ARX) inputs on the electromechanical impedance measured at the piezoelectric sensors are used as nonlinear features to monitor early-stage fatigue crack's initiation and its growth that might be developed in the host structure subjected to a fatigue loading condition. The applicability of the proposed wireless SHM and nonlinear impedance methods is demonstrated throughout an experimental study using a simple test sample under a fatigue loading condition. Finally, this paper concludes with a discussion of further studies and future applications.