The non-destructive testing (NDT) group includes shearography, computerised tomography and X-ray analysis. Shearography is a laser-assisted, optical measurement method which is capable of revealing irregularities such as air bubbles in the tyre. X-rays and computerised tomography are employed when a deeper look into the material is required. Continental only has the associated equipment and laboratories for tyre analysis at its Hanover-Stöcken site, not least because of the physical infrastructure required. The cellar of Building 6 has 125 cm thick steelreinforced concrete walls and doors with 10 mm of lead cladding to provide the necessary radiation protection.
Continental has been using computerised tomography since 1997 and over the years the time required for a 2D scan has dropped from one hour to three minutes.
The linear accelerator has sufficient power to “see” right through even thick-walled truck tyres without image artefacts, which means that even the tiniest deviations in construction can be identified.
One particular feature is the simulation of many different service conditions, i.e. the recreation of different load and tyre pressure conditions during the scan. This makes it possible to carry out comparative test series with many different tyre specifications.
Each year, some 2,000 tyres for testing confront the team with new challenges and yield surprising insights. The results help R&D's product developers understand the ins and outs of the material and so optimise and perfect their simulation models. Support is also provided for other business areas − such as investigating hydromounts for Vibration Control.