Monitoring micro fractures on airplane parts and checking the physical integrity of infrastructure has now become much easier and more accurate thanks to carbon black tech.
Cheaper to build, and lighter; dense sensor net using the new material offers a cost-effective solution…
Researchers from the Hong Kong Polytechnic University have developed a bold and innovative type of sensor based on nanocomposites. These can be useful on flat or structural surfaces with curves. Additionally, they can deliver data in real-time. It is a lightweight material with a low-cost fabrication and implementation method. It therefore allows the usage for large quantities in a sensor network. There can be easy analysis of data for structural flaws in trains, airplanes, ships, bridges and train tracks.
The material, discovered by Department of Mechanical Engineering, led by Professor Su Zhongqing and Professor Zhou Limi, makes use of a hybrid of conductive nanoparticles, polyvinylidene fluoride (PVDF), 2D graphene, and carbon black. The resulting nanocomposite sensor can therefore apply to different sizes of structures and engineering applications, even on a moving vehicle.
Alternatively, it can be applied from a moving vehicle onto a track or any large structure, like bridges for example. The sprayable nature of the material also allows usage over a large area for real-time monitoring of the stresses on various materials.
Carbon Black Tech
The sensing technology comprises the nanocomposite sensor along with an ultrasound actuator. The actuator uses guided ultrasonic waves (GUWs) which are picked up by the sensors. The generation of GUWs as they travel through the monitored material show discrepancies when they encounter a break (a microfracture or a fissure). This leads to a wave scattering of the GUWs. And that in turn provides readings from the sensors that enable engineers, researchers, or maintenance personnel to the discover the location of the break.
Conventional sensors using ultrasound cost more than $10 each and weigh a few grams. These are from lead zirconate titanate (PZT) and there is limit in use by their cost and weight. These are usually stiff and application on curved structural surfaces is not possible. It penalizes the host material with the additional weight of numerous sensors that can do the job.
In comparison, the nanocomposite sensor will cost less than $0.50 each and weigh 0.04 grams. It is possible to manufacture these in large volume to create a much denser sensor network than conventional ultrasound sensors. Cheaper to build, and a light sensor net using the new material offers a cost-effective solution. A wider range of structures can gather more data.
The added bonus to using the nanocomposites is that the structure can be moving or in use while during monitoring, eliminating downtime or the requirement to shut down operations just to do the check.