Crash testing is an essential part of car manufacturing, involving the deliberate destruction of vehicles to understand how they perform in accidents. The process allows car makers to improve their designs and ensure the safety of their vehicles. Mercedes-Benz has been at the forefront of crash testing advancements, recently becoming the first manufacturer to subject two electric cars to a crash test with one another and the first to X-ray a crashing car in real-time.
The X-ray test conducted by Mercedes-Benz took place at the Ernst Mach Institute in Freiburg, Germany. They used a C-Class saloon and a linear accelerator as the X-ray camera. The test involved a side impact, where a heavy barrier was slammed into the stationary car at 37mph. Inside the car, a specially designed SID II dummy, representing the female body, was placed closest to the impact.
The X-ray images were created by a linear accelerator working at a high frequency of 1kHz. It looked down on the car from above, while a flat detector below the car acted as a digital receiver. As the X-rays passed through the car’s structure and the dummy, they were absorbed to varying degrees by the materials, generating varying tones that created a black and white image. This process is similar to that of a hospital X-ray machine or an airport luggage scanner.
The X-ray pulse had a duration of just a few microseconds, allowing still images of the deforming structure to be recorded without any blurring due to movement. The linear accelerator generated a continuous stream of X-ray pulses, capable of producing up to 1000 images per second. In the few milliseconds of impact, about 100 still images were captured, which could be viewed individually or combined into a video.
The results of the X-ray test provided valuable insights into what happens to both the car and the dummy during a crash. For example, it revealed how the thorax of the dummy is compressed in a side impact and how specific components of the car’s structure deform. This detailed information helps investigators understand the dynamics of a crash and make further improvements to vehicle safety.
Importantly, the X-ray system used by Mercedes-Benz did not interfere with other analysis tools, such as conventional cameras mounted inside the car. Safety measures were also in place to protect staff and prevent exposure to potentially harmful radiation. Dosimeters were used to monitor radiation levels, and the facility was equipped with a 40cm-thick concrete wall and a 45-tonne protection door at the entrance.
By pushing the boundaries of crash testing, Mercedes-Benz is leading the way in enhancing vehicle safety. Their use of X-ray technology provides unprecedented insights into the effects of a crash on both the car and the occupants. This level of understanding allows for continuous improvements in vehicle design and safety standards. As technology advances, it is likely that more car manufacturers will adopt similar methods to ensure their vehicles provide the highest level of protection in accidents.