Combined Energy Harvesting and Structural Health Monitoring Potential of Embedded Piezo-Concrete Vibration Sensors

Piezoelectric materials have proven their efficacy for both energy harvesting and structural health monitoring (SHM) individually. Piezoelectric ceramic (PZT) patches, operating in d31-mode, are considered best for SHM. However, for energy harvesting, built up configurations such as stack actuators are more preferred. The proposed study in this paper provides a proof-of-concept experimental demonstration of achieving both energy harvesting and structural health monitoring from the same PZT patch in the form of concrete vibration sensor (CVS), designed specifically for RC structures. This packaged sensor (CVS), composite in nature, has better compatibility with surrounding concrete and can withstand the harsh conditions encountered during construction. The paper covers experiments carried out in the laboratory environment to measure the voltage and the power generated by a CVS embedded in a life-sized simply-supported RC beam subjected to harmonic excitations. An analytical model is developed to compute the power output from the embedded CVS, duly considering the effect of the shear lag associated with the bonding layers between the encapsulated PZT sensor and the surrounding concrete. The performance of the CVS is compared with the surface-bonded PZT patch. Utilization of the same patch for SHM through a combination of the global vibration and the local electro-mechanical impedance (EMI) techniques is also covered. Harvesting potential of vibration energy by PZT sensors during idle time is experimentally demonstrated and extended to real-life structures based on the validated analytical model.