Using Nanotubes To Detect Damage To Composite Airplanes

Composite materials are an increasingly popular material for building airplanes because they offer high strength and low weight. But if something like a luggage cart hits the plane, determining the extent of the damage can be time consuming and costly, write the guys from wired.com.

“With aluminum, if you hit it, there’s a dent,” says Brian L. Wardle, an associate professor of aeronautics and astronautics at Massachusetts Institute of Technology. “With a composite, oftentimes if you hit it, there’s no surface damage, even though there may be internal damage.”

Wardle and a team of researchers have developed a way of using heat-sensitive cameras to detect internal damage to composite structures. The only catch is the composite material must include carbon nanotubes, which generate the heat needed for the test to work. But there’s an advantage there, too: the carbon nanotube hybrid materials Wardle is developing have so far proven to be stronger and tougher than current composites.

The technique is similar to one current method that relies upon infrared thermography. With today’s thermo technique, the structure in question must be heated with an external heater to check for an abnormal flow of heat. It can be cumbersome, and checking a large area is time-consuming.

Wardle’s approach applies electric current to the structure, causing the nanotubes to heat. Cracks or delamination will redirect the flow of heat and can be seen with a heat-sensitive camera or goggles.

Hurdles remain to developing a means of manufacturing large quantities of nanotube composite, and extensive testing would be needed to ensure the strength and durability of the material. But Wardle says the technology would allow airlines and the military to inspect aircraft faster and easier than is possible today.

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