Textile-based strain sensors for fiber-reinforced composites under tension, compression and bending

This research addresses the challenging task of monitoring the structural integrity of fiber-reinforced composite (FRC) components under complex loading conditions. Ensuring the safety and functionality of these components is critical but economically challenging. Therefore, this study presents an innovative approach using textile-based strain sensors that are cost-effective and structurally compatible with carbon fiber-reinforced plastic (CFRP) components. The investigation includes the systematic electromechanical characterization and comparison of four different sensor materials at the yarn and composite scale in various test scenarios. Cyclic tensile, compression, and bending tests of CFRP specimens are performed and show good reproducibility of sensor signals within the elastic range, with significant agreement observed with applied strain measurement methods, particularly in tensile tests. Although there are minor deviations in compression and bending evaluations, the signals are still meaningful for in-situ detection of complex loading patterns, crack initiation, and structural failure. The study demonstrates that the integration of textile-based sensor yarns allows for continuous structural health monitoring (SHM) of CFRP components under various loading scenarios, including tensile, bending, and especially compressive loads.