The experiment begins with a crash barrier hitting the C-Class sedan right next to it at 60 km per hour. The difference of this crash test, which is special even for experts, is located in a frame above the vehicle on the ceiling of the hall: A linear accelerator acts as an X-ray camera. The Fraunhofer Institute for High Speed Dynamics and the EMI (Ernst Mach Institute) in Freiburg conducted the world's first X-ray collision with a real car for Mercedes-Benz. The vehicle included a SID II mannequin with female anatomy, specially designed for side impact tests, facing the direction of the collision.
This demonstration (proof of concept) demonstrates that high-speed X-ray technology can be used to visualize highly dynamic internal deformation processes. Thus, previously unseen deformations and the processes they undergo become visible. A large number of high-resolution images enable precise analysis.
Mercedes-Benz's X-ray collision is a milestone in the development of future vehicles, says Markus Schäfer, Member of the Board of Management and Chief Technology Officer of Mercedes-Benz. He underlines that he believes that a direct look inside the vehicle, which was previously impossible to see, will help to achieve important results to further improve vehicle safety. Head of Fraunhofer EMI Crash Testing Center Dr. While Malte Kurfiß stated that this successful trial provided valuable information to further optimize the technology for obtaining previously inaccessible information, Mercedes-Benz Vehicle Safety Director Prof. Dr. Paul Dick states that the world's first X-ray accident helps them learn what happened inside the vehicle and on the mannequins during an accident, and that X-ray images offer the opportunity to improve the model quality of digital prototypes.
Up to 1.000 images per second can be acquired with ultra-short X-ray technology
The Mercedes-Benz vehicle safety department had been exploring the use of X-ray technology in crash tests with colleagues at EMI for years. The decisive factor for the breakthrough was the use of a linear accelerator with 1 kHz technology as a radiation source. This device is much more powerful than the X-ray flashes used in previous attempts, and the linear accelerator's photon energy can reach up to nine megaelectron volts. In this way, all materials commonly used in vehicles can be scanned. The duration of the X-ray pulse is only a few microseconds, making it possible to record the deformation processes in the crash test without motion-induced blurring. The linear accelerator also produces a continuous stream of these X-ray pulses. This means that up to 1.000 images per second are possible. This is approximately 1.000 times more than traditional X-ray methods.
During crash testing, beams pass through the bodywork and dummies. The flat detector under the test vehicle serves as the digital image receiver in the X-ray system. The images obtained here affect the gray value that can be seen later, similar to X-raying of luggage at the airport or x-ray images.
Within milliseconds of impact, the X-ray system takes approximately 100 still images. These images, combined into a video, provide important information by detailing what happened to the safety components and the dummy during the collision. In this way, it becomes possible to observe in detail how the mannequin's chest is compressed or how the vehicle is deformed. The important part on the way from research to industrial application is that X-ray collision does not affect any other analysis tools. Even the interior cameras in the crash test vehicle continue to record without any distortion.
EMI experts have also prepared a comprehensive radiation protection guide for X-ray accident. Dosimeters are used as monitors to ensure that workers are not exposed to radiation. While government officials approved the operation of the facility in accordance with legal requirements, protection measures include an additional 40-centimeter-thick concrete wall around the building and a guard gate weighing approximately 45 tons.
Crash tests: part of Mercedes-Benz's "Real Life Safety" philosophy
On September 10, 1959, the first crash test in Mercedes-Benz history took place in an open field close to the factory in Sindelfingen. A test vehicle was driven directly into a solid obstacle. This opened a new page in safety research at Mercedes-Benz. Because it has become possible to examine the behavior of both vehicles and passengers in collisions under realistic conditions using test cars and mannequins. Analysis of accident investigations and crash tests form the basis of Mercedes-Benz's "Real Life Safety" philosophy.
Mercedes-Benz carries out nearly 900 crash tests and around 1.700 'sled tests' each year at its Vehicle Safety Technology Center in Sindelfingen. In the sled test, a test sled is accelerated and braked. The object (vehicle or its component) under test is mounted on the sled and exposed to forces that are likely to occur during an actual crash. These skid tests enable protection systems, especially seat belts, to be tested without damage.
The world's first public crash test with two fully electric vehicles in autumn 2023 also shows that at Mercedes-Benz, safety is not about drive systems. The EQA and EQS SUV models crash into each other in a real accident scenario at a speed of 56 km/h and with 50 percent overlap, confirming the high level of passenger protection. The interior and high-voltage battery of both vehicles remain intact as intended, the doors can be opened and the high-voltage systems automatically shut down.