|Space foil helping to build safer cars|
|MAT / MATERIALS / Sunday, 18 March 2012 20:51|
This ‘space’ foil has been transformed into a new super-thin and accurate sensor used by VW to measure every deformation suffered by cars during crash tests.
It all started in the early 1990s, when German engineer Paul Mirow was working on Europe’s Hermes spaceplane at Technical University Berlin. Hermes was planned as a reusable manned vehicle launched on Ariane 5.
To map the pressure distribution on the wings as Hermes returned through the atmosphere, a new sensor was needed because regular instruments were too bulky and added unrealistic drag. So Paul’s team turned to a special ‘piezoelectric’ foil to do the job.
Piezoelectric materials have a special property that converts physical effects like vibration and pressure into minute electric pulses. “It takes movement, forces or vibration, and turns it into an electrical signal,” Paul notes.
In foil form, piezoelectric materials can serve as extremely lightweight sensors, able to cover an entire surface without distorting the results by adding drag.
“The piezoelectric foil is very thin, about 30 microns – a third of the thickness of a human hair,” explains Paul.
While other types of sensors create obstacles, with these piezoelectric foils, “You can just glue it to the surface, without creating any disturbances in the structure.”
One was even created for a dental company: “We painted a tooth with piezoelectric paint so they could measure the forces created by the toothbrush on the molar.”
Making cars safer
One of the most exciting applications was developed for VW to use in their crash tests.
VW hoped that the space sensors would solve a problem encountered in crash tests: sensors on cars are often destroyed at impact, making it difficult to collect highly accurate data throughout the crash process.
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|Last Updated on Sunday, 18 March 2012 20:54|