Using nanotubes to detect and repair cracks in aircraft wings, other ...( Troy N.Y. Adding even a small amoun...)

Troy, N.Y. Adding even a small amount of carbon nanotubes can go a long way toward enhancing the strength, integrity, and safety of plastic materials widely used in engineering applications, according to a new study.

Researchers at Rensselaer Polytechnic Institute have developed a simple new technique for identifying and repairing small, potentially dangerous cracks in high-performance aircraft wings and many other structures made from polymer composites.

By infusing a polymer with electrically conductive carbon nanotubes, and then monitoring the structures electrical resistance, the researchers were able to pinpoint the location and length of a stress-induced crack in a composite structure. Once a crack is located, engineers can then send a short electrical charge to the area in order to heat up the carbon nanotubes and in turn melt an embedded healing agent that will flow into and seal the crack with a 70 percent recovery in strength.

Real-time detection and repair of fatigue-induced damage will greatly enhance the performance, reliability, and safety of structural components in a variety of engineering systems, according to principal investigator Nikhil A. Koratkar, an associate professor in Rensselaers Department of Mechanical, Aerospace and Nuclear Engineering

Details of the project are outlined in the paper In situ health monitoring and repair in composites using carbon nanotube additives, which was published online this week by Applied Physics Letters. Rensselaer graduate students Wei Zhang and Varun Sakalkar were co-authors of the paper. The team has been working on the project for more than 18 months.

The majority of failures in any engineered structure are generally due to fatigue-induced microcracks that spread to dangerous proportions and eventually jeopardize the structures integrity, Koratkar said. His research is looking to solve this problem with an elegant solution that allows for real-time dia
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