Preliminary Development of Flexible Printed Strain Gauges for Structural Health Monitoring

Printed electronics offer a flexible and scalable alternative to conventional strain gauges for structural health monitoring (SHM) applications. This paper presents the preliminary development and evaluation of printed strain gauges. Conductive silver inks were printed to fabricate resistive strain sensors on flexible substrates using a materials dispensing printer (Voltera). The study focuses on optimizing printed sensors fabrication, assessing its electrical and monitoring performances, and comparing with commercially available strain gauges. Both printed strain gauges and commercial strain gauges were attached on opposite sides onto metal and composite plates for fatigue testing. Despite low unstrained resistances of about 10 Ω, the resistance changes under strain for the printed strain gauges were comparable to that of commercial strain gauges (350 Ω). Under 1000 cycles of tensile loading, the changes in resistance were consistent. Therefore, results demonstrate promising sensitivity, repeatability, and fatigue resistance.