'Sensing Skin' To Help Detect Damage In Concrete Structures

Rawatbhata is a town in Rajasthan, India. About 11 Kms away from it is a nuclear power plant operated by Nuclear Power Corporation of India Ltd (NPCIL). Temperatures in Rajasthan swing from as high as 50.8 degrees Celsius to freezing 2.2 degrees Celsius. The safety-critical cement-concrete structures at the nuclear facility have to withstand these searing and frigid temperatures alike. Any undetected damage to the structure could have catastrophic effects. A possible solution to the problem could be a novel 'sensing skin' technology developed by researchers at the North Carolina State University and the University of Eastern Finland serves as an early warning system for concrete structures, allowing authorities to respond quickly to damage.


The 'sensing skin' actually is an electrically conductive paint. This paint can be manufactured using conductive materials such as copper which makes it inexpensive. Electrodes are applied on the surface of the structure. The sensing skin is then painted onto the structure, over the electrodes. A computer program then runs a small current between two of the electrodes at a time, cycling through a number of possible electrode combinations. Every time the current is applied, the computer records the potential at each electrode on the structure. The electrical conductivity of the skin is calculated using this data and if the conductivity is found to be reduced, some crack or other damage is said to have occurred. An advanced suite of algorithms also helps to determine the location and intensity of the damage.
A research paper in this regard authored by Dr. Mohammad Pour-Ghaz of NC State and Dr. Aku Seppänen of University of Eastern Finland was presented in the Smart Materials and Structures Journal. The authors said that the research was primarily directed at critical infrastructure such as nuclear waste storage facilities and dams and bridges so that authorities could address these problems quickly before they become big problems.

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