In situ fatigue crack detection using piezoelectric paint sensor

This article reports the recent development of a surface fatigue crack detection technique based on the use of surface-mount piezoelectric paint sensor. Polymer-based piezoelectric paints that can be directly deposited onto the surface of host structures are being utilized to make the sensor for surface crack detection. Because of its electromechanical coupling properties, voltage signals can be generated by the piezoelectric paint sensor when subjected to mechanical strain in its film plane. Results from recent development of the piezoelectric paint-based surface crack detection technique indicate that piezoelectric paint sensors with a special electrode design can potentially provide an effective method to detect fatigue cracks occurring in structural surfaces. A simple damage index is defined to determine the occurrence of surface cracks in a pre-specified region. However, complex sensor electrode patterns may be necessary in some cases to improve the spatial resolution of surface crack detection. Experiments conducted to validate this surface crack detection technique are also described in this study.