Novel approach for damage detection in multiscale CNT-reinforced composites via wireless Joule heating monitoring

A novel method for strain and crack propagation monitoring based on Joule heating capabilities of multiscale carbon nanotube reinforced glass fiber composites (GFRP-CNT) is reported. The manufactured GFRP-CNT composites show good Joule heating capabilities with heating rates ranging from 3 to 56 °C min−1 at applied voltages from 30 to 105 V, respectively. Multiscale GFRP-CNT composites present similar tensile strength and Young's Modulus than conventional GFRP but very enhanced failure strain due to the toughening effect of CNTs. The wireless monitoring via Joule heating shows a very high sensitivity and strain resolution (with values ranging from 0.01 to 0.1%) for early crack initiation and subsequent propagation. Finally, the thermal IR imaging also allows to create a complete mapping of the health of the structure during the whole test, allowing the detection, localization and quantification of early damage and, thus, proving an outstanding potential for Structural Health Monitoring (SHM) applications in comparison to other conventional techniques.