The use of silver conductive paint for crack propagation sensor customization

The paper presents experimental verification of customized resistive crack propagation sensors as an alternative for common SHM techniques. To manufacture new sensors, electrically conductive paint with silver microparticles is utilized to prepare tailored measuring grid on epoxy or polyurethane coating as a driving/insulating layer. That method is designed to enhance functionality and usability compared to commercially available crack gauges. By using paint with conductive metal particles, the shape of sensor measuring grid can be more easily adapted to the structure, while in the previous approach only few grid-fixed sensors are available. Fatigue tests on coupon CT specimen as well as thin aluminum plate are presented and discussed to evaluate the ability of the developed sensors to detect and monitor fatigue cracks. Two types of data acquisition system with various sensing layer interconnection is proposed, in which a series of conductive stands are connected to Wheatstone bridge or become a part of RLC band pass filter.