Identifying damaged aircraft parts is a tricky business. Unless there are visual signs of damage, such as buckling or a dent, the part has to be X-rayed to determine whether it may contain microfractures that could endanger the aircraft.
So the US Air Force funded a US company called Luna Innovations to develop an easier way to spot damage.
The technique that Luna Innovations has come up with is to coat an aircraft part with a polymer containing a fluorescent dye held in tiny capsules. If that part is struck with force or twisted beyond a certain limit, the capsules break releasing the dye. A visual inspection of the aircraft then reveals exactly where any damage might have occurred.
Justin Mullins, New Scientist contributor
Read the full pressure-sensitive paint patent application.