Technology.am (Oct. 2, 2009) — If a bird collides with a plane the consequences can be fatal, not only for aircraft but also for the creature itself. The impact can deform the structure of the aircraft fuselage, causing stresses in the material which can later turn into cracks.
Now sensors in the aircraft skin will detect such damage at an early stage and simplify maintenance and repair work. If they discover any dents or cracks they will send a radio message to a monitoring unit.
The sensors can be located at inaccessible places on the aircraft and they don’t need any cables or batteries. They draw their energy from the temperature difference between the outside air (about minus 20 to minus 50 degrees Celsius) and the passenger cabin (about 20 degrees Celsius).
Researchers at the Fraunhofer Institute for Physical Measurement Techniques IPM in Freiburg, Germany, are developing the energy supply system for the sensors.
“We use thermoelectric generators, developed in cooperation with Micropelt GmbH, and adapt them so that they work efficiently,” explains Dr. Dirk Ebling, scientist at the IPM. Thermoelectric materials are semiconductors which generate electric power under the influence of a temperature difference.
To couple the thermoelectric generator to the warm and cold environments, the scientists set up a climate chamber in which the temperature profile of the aircraft fuselage is simulated.
These energy-autonomous sensors could be useful in automobiles where they could help to reduce weight by removing the need for heavy cable assemblies. They would also be useful in old buildings to monitor dampness.
A sensor system integrated in a running shirt could monitor an athlete’s pulse during training, and hearing aids could obtain their energy from body heat.