A coated carbon nanotube sensor network for in-situ active sensing of ultrasonic elastic waves

A coated sensor network made of carbon nanotubes (CNTs) was developed, to facilitate insituactive sensing of ultrasonic elastic waves (UEWs). The dynamic particulate motion inducedby UEWs modulates the infrastructure of CNT networks, and consequently changes thepiezoresistivity measured by the coated sensor network. Innovatively, the sensor network can besprayed and deposited onto structures, with which structural damage can be characterized. Such asensing philosophy retrofits conventional sensor network design, by providing a novel, quick andconvenient means to configure a sensor network with quasi-dispersed sensing elements, andcircumvents the possible drawbacks associated with the use of distributed sensors (e.g., PZT). Itwell compromises “sensing cost” and “sensing effectiveness”. In addition, the coated sensornetwork can flexibly accommodate structures of various properties and geometries (metals orcomposites, flat or curved). The effectiveness of the developed sensor network in sensing UEWswas demonstrated experimentally. To corroborate experimental results, a nano-scale numericalmodeling was also developed, to observe a good matching in between.