Cycling crash helmets have just one purpose: to protect the cyclist‘s head. But only completely damage-free helmets do the job properly. It is therefore recommendable to buy a new one every now and again, but nobody wants to throw away a perfectly good helmet. It would be better to know for certain that this is really necessary. A new process developed by German research scientists at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg makes this possible.
The polymer materials or plastics produced by the process start to smell if they develop small cracks. Large cracks really cause a stink. The smell comes from odoriferous oils enclosed in microcapsules. "Cyclists often replace their helmets unnecessarily after dropping them on the ground, because they cannot tell whether they are damaged or not. The capsules eliminate this problem. If cracks form, smelly substances are released," explains Dr.-Ing. Christof Koplin, research scientist at the IWM.