Crack detector

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 structure’s electrical resistance, the researchers have been 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 Nikhil A. Koratkar, an associate prof in Rensselaer’s Department of Mechanical, Aerospace and Nuclear Engineering.