Health Monitoring of Moving/Rotary Structures: An Electromechanical Impedance Approach Using Integrated Piezoceramic Transducers

This chapter presents development of a novel structural health monitoring methodology used for incipient damage detection in moving structures. This method is built upon implementation of low-cost deposition of piezoceramic transducers on crucial substrates together with electromechanical impedance (EMI) to provide a practical solution to damage/fault detection of moving structures that suffer from mechanical fatigue, thermal fatigue or corrosion, before any catastrophic failure. Important steps towards application of such technology are: i) Chemo-physical fabrication of piezoceramic transducers, i.e., deposition of precursor solutions or piezoelectric materials, on geometrically irregular structures; ii) Development of a portable impedance-based transceiver and signal processing algorithm capable of transmitting actuating signals as well as receiving and analyzing response signals to/from piezoelectric transducers, respectively; iii) Development of a monitoring algorithm, and iv) Methodology verification through bunch of semi-filed tests by building the prototype of a moving structure. Multiple characterizations are performed to assure the micro and macro-structural functionality, accuracy, and precision of fabricated transducers. To verify the functionality of the custom-built system, electromechanical response of the transducers and the results obtained from the transceiver are compared with commercially available piezoelectric wafers and standard impedance analyzers. Frequency response of transducers measured in a wide bandwidth shows obvious frequency shift and change in the admittance/ impedance amplitude corresponding to the resonance/anti-resonance peaks at pristine vs. damaged conditions. Furthermore, for rotary structures, rotational speed and temperature play important role in this method. Application of this method could be extended to moving structures such as airplane engine blades, fuselage frames, wing ribs, helicopter main rotor assembly, critical parts of the exploration rovers, satellite loaded modules and thrusters, moving links/joints on the international space station, rotors in hydroelectric or nuclear power plants, autonomous underwater vehicles, submarine propellers, hydro/diving planes, wind turbines, hot/cold rollers in steel production lines, drones, mobile robots, etc.