Toward field implementation of carbon nanotube-based composites for monitoring and repairing fatigue damaged steel structures

Fatigue damage of steel structures is one of the major reasons for deficient infrastructure. Adhesively-bonded fiber reinforced polymer (FRP) materials are an excellent candidate for repairing these fatigue-damaged structures. However, one of the major drawbacks of this repair scheme is that its visual inspection is difficult. Our research group developed and experimentally evaluated a novel configuration of FPR sheets by embedding a carbon nanotube (CNT)-based sensing layer in the adhesive joint, allowing condition monitoring capabilities. We have also found that the CNT sensor can be employed individually to detect and continuously monitor a fatigue crack. For the field implementation of this innovative fatigue crack sensor, we have developed and evaluated a protective layer for the sensor and a low-cost and reliable data acquisition system.