Nanotube network detects cracks

Researchers have discovered a means to detect and identify damage within advanced composite materials using a network of carbon nanotubes which act like human nerves.

The discovery at the University of Delaware could help scientists better predict the life span of various composite materials. It could also become an important tool in monitoring the health of composite materials used in the construction of a variety of products, including commercial airliners.

Tsu-Wei Chou, Pierre S. du Pont Chair of Engineering, and Erik Thostenson, assistant professor of mechanical engineering, have been studying the reinforcement of fibre composites with carbon nanotubes.

Composite materials are generally laminates, sheets of high-performance fibres, such as carbon, glass or Kevlar, embedded in a polymer resin matrix. Traditional composite materials have inherent weaknesses because the matrix materials-plastics-surrounding the fibres are less strong than the fibres.

This results in weak spots in composites in the interface areas in the matrix materials, particularly where there are pockets of resin. As a result, defects, including tiny microcracks, can occur. Over time, those microcracks can threaten the integrity of the composite.