Self-sensing attained in carbon-fiber–polymer-matrix structural composites by using the interlaminar interface as a sensor

Self-sensing is valuable for structural materials, especially those for smart structures. It does not involve the use of embedded or attached sensors, as the structural material is itself the sensor. Self-sensing was attained in carbon-fiber–polymer-matrix structural composites by using the interlaminar interface (i.e., the interface between the laminae of continuous fibers) as a sensor. The attributes sensed were temperature, moisture, damage, and stress. In the case of temperature sensing, the interlaminar interface functioned as either a thermistor or a thermocouple junction. The thermocouple approach required the fibers in the contacting laminae to be dissimilar, whereas the thermistor approach did not. By using two crossply laminae, a two-dimensional array of sensors was attained for spatial distribution sensing.