SWCNT-thin-film-enabled fiber sensors for lifelong structural health monitoring of polymeric composites - From manufacturing to utilization to failure

With glass, polyaramid, nylon and polyethylene terephthalate as the fiber substrate, a continuous spray coating and winding process was developed for fabricating SWCNT-FibSen sensor - single-walled carbon nanotube (SWCNT) thin film enabled 1D fiber sensor. The microstructures of the SWCNT-FibSen and its piezoresistive behavior were respectively characterized by scanning electron microscopy and Raman spectroscopy and evaluated by the coupled electromechanical tensile test. With embedding the SWCNT-FibSen sensor in the fiberglass prepreg laminates at different orientations and locations, its use for multipurpose sensing in life-long (from manufacturing to failure) structural health monitoring of high-performance polymeric composites was demonstrated. During the manufacturing process, the sensor was able to provide valuable local resin curing information. After the manufacturing process, the sensor was useful in mapping the stress/strain states of the host composite under different deformation modes - tension, bending, compression and failure. The integrity of the sensing performance of the embedded SWCNT-FibSen sensor was demonstrated upon a 10,000-cyclic coupled electromechanical test.