Computer simulations may speed up development work and also reduce cost (no need to crash so many cars as before) but physical crash tests still have a place in the development program of a new model. Although simulations with powerful computers allow engineers to see what happens to the structure of a car as it crumples during an accident, crash tests with actual full-sized vehicles are still conducted to confirm the safety of the design in the real world.
Proof of concept demonstrated
At Mercedes-Benz, which is among the world leaders in automotive safety, both approaches are used in vehicle development. The testing technology has constantly been advanced and now, there is a technical sensation which has been demonstrated in a joint project with the Fraunhofer-Society, a leading organisation for applied research in Europe.
For the first time, all processes in vehicle structures and the effects on the dummies inside can be seen. There are already high-speed cameras around the cabin but they show what happens on the surface. This new technology shows an x-ray view of everything while the crash is taking place.
The images using high-speed X-ray technology allow visualisation of the highly dynamic internal deformation processes. Previously invisible deformations and their exact processes are now transparent, allowing more precise analysis.
Linear accelerator as radiation source
The decisive factor for the breakthrough technology was the use of the linear accelerator with 1 kHz technology as the radiation source. The device is far more powerful than the X-ray flashes previously used in trials. The photon energy of the linear accelerator is up to 9 megaelectron volts. This allows all materials commonly used in vehicle construction to be screened.
1,000 images per second
The duration of the X-ray pulse is only a few microseconds. This makes it possible to record deformation processes in the crash test without motion blur. The linear accelerator also generates a continuous stream of these X-ray pulses. This means that up to 1,000 images per second are possible, which is about 1,000 times as many as with conventional X-ray procedures.
In the milliseconds of the actual impact time, the X-ray system shoots around 100 still images. Combined into a video, they provide insights into what happens inside safety-relevant components and in the dummy’s body during a crash. In this way, it is possible to observe in detail how the thorax of the dummy is pressed in or how a component is deformed.
“The Mercedes-Benz X-ray crash sets a milestone in the development tools of the future. With a direct view into the hidden interior, it can help to draw important conclusions for the further improvement of vehicle safety. Mercedes-Benz thus confirms its role as a safety pioneer in automotive engineering,” said Markus Schafer, Member of the Board of Management of Mercedes-Benz Group AG, Chief Technology Officer.
