Strain Monitoring of Fiber Reinforced Composites Based on Carbon Nanotube Thin Film Sensor

Abstract

Carbon nanotube film has a microporous material property which make it can be integrated with composite material and does not change the original structural characteristic of composites. Moreover, its excellent piezoresistive properties can be used for real-time and online monitoring the strain of composite materials. In the present work, carbon nanotube thin film sensor had been prepared by the method of vacuum filtration, and then it has been attached to the surface of fiber reinforced composites for the strain monitoring of composite material. Experimental results of tensile tests show that the resistance rate of carbon nanotube film sensor will have a sudden change when the elastic limit is reached. And when the maximum stress is greater than the elastic limit, the residual resistance of sensor increased rapidly with the increase of the fatigue cycle. Nevertheless, the residual resistance change rate and sensing coefficient could stabilize after sever cycles. In conclusion, when the strain applied is not bigger than the elastic limit, carbon nanotube thin film sensor has a very good ability for monitoring the strain of composites synchronously and stably.