Carbon Nanotube Based “Smart Skin” That Can Sense Structural Damages

A team of engineers working at the University of Delaware recently developed a completely new method for keeping a check on the structural health of infrastructure with the help of “smart skin” derived from carbon nanotube composite. The composite it is derived from is robust mechanically and has the ability to adhere to any surface and shape. In short, it is perfect to keep a check on the health of structures, bridges, or roads. 

 

 

The smart skin makes use of a new technique called EIT or Electrical Impedance Tomography for signalling those regions of structures that might be of bad quality. EIT makes use of surface electrode measurements that map the 2D conductivity of skin’s surface. The team working on it examined a carbon nanotube composite square that had 32 equally spaced electrodes near the boundary in order to measure the surface conductivity. 

 

The main idea is simple, create a 2D image of skin electrical conductivity at two different timings such as before and after a natural calamity. When you compare the two images you can easily measure the difference in conductivity between the two. The map will give you a detailed idea of the structural damage that was caused due to flood or earthquake. The engineers did some tests over various types of simulated structural damage along with several square holes in the skin, a simple scratch in the skin can simulate crack to show the extent of damage that was done via the drop weight tester. 

 

The structural engineer, Thomas Schumacher, adds, “Although we did encounter some issues with the size of cracks being overestimated and their shapes not being well represented, overall our EIT methodology was able to detect the initiation of damage well before it was visible with infrared thermography. We are in the process of making improvements to the EIT algorithm to increase its accuracy. After that, we plan to demonstrate it in the laboratory, with an aim toward scaling it up for future monitoring of real structures.” 

 

There are so many horror stories that accompany several engineering marvels, a small crack and who building comes down endangering lives of all people who are near or under it. There are so many factors that play a key role in such disasters such as deterioration, aging, hurricanes, earthquakes, and so forth. Many times the damage caused by these is invisible. So, it is necessary to keep a check on the health of such structures so that accidents and disasters are kept at bay.