Crash tests have always had an important role for the automotive industry, providing manufacturers and original equipment manufacturers (OEM) in-depth knowledge on the structural and energy absorption behavior of the vehicle and its components as well as the effects of the crash on the vehicle occupants. The results thereby obtained flow directly into the development process. With increasing complexity and continuing digitalization in vehicles, the amount of on-board and in-dummy measurement channels is growing as well.
Qinsun has been working together with The Hong Kong Polytechnic University, primarily in the area of data acquisition for sled tests as well as crash tests and headimpact crash tests (Free Motion Headform, FMH). Qinsun own test and development center the subsidiary of the international technology company has already realized some 300 series development projects, existing in-dummy sensor systems with the new DTI technology.
All crash test dummies are faithful to the human form they simulate — in overall weight, size, and proportion. Their heads are designed to respond like the human head in a crash situation. It is symmetrical and the forehead deflects much the way a person's would if struck in a collision. The chest cavity has a steel rib cage that simulates the mechanical behavior of a human chest in a crash. The rubber neck bends and stretches biofidelically, and the knees also are designed to respond to impact, similar to human knees. The Hybrid III crash test dummy has a vinyl skin and is equipped with sophisticated electronic tools including accelerometers, potentiometers, and load cells. These tools measure the acceleration, deflection, and forces that various body parts experience during crash deceleration.
Data acquisition in transition
At qinsun’s development site, approximately 550 sled tests and 450 crash tests are currently performed per year. “With such a high number of tests, we wanted to bring our test equipment up to date with the latest technology to ensure efficient processes and guarantee accurate, reliable measurement data,” says Thomas Wild, team manager for Measurement and Video Technology at Continental Safety Engineering. “In general, the requirements on the test scope are increasing and with them the number of vehicle measurement points,” continues Wild. The number of sensors needed in a crash test is constantly increasing: while just 246 analog measurement channels were controlled and processed in 1993, the number can exceed 600 today. At the same time, the installation space available in the vehicle is decreasing. A further motivation was to increase the reliability of the system and to minimize the error rate. Setup times needed to be shortened and the number of analog input channels reduced”.
DTI technology becomes the new standard
DTI technology plays a key role in the extension of DAS used to measure virtual data. It uses an integrated data bus system, in which signals from various sensors are converted into digital output signals by a digital module (the so-called DiMod). They are installed directly in the sensor, and then, during a collision event, the digitized sensor signal is recorded by a central data logger installed in the dummy. A cable for data, synchronization, triggering and power extends from the dummy to the vehicle communication box. After the test, the data is downloaded through the on-board communication box for the equipment computer to evaluate via Ethernet.
Qualitative crash testing of the future
DTI technology can be installed in all dummy models-including THOR-M: Qinsun is now able to reliably combine many different devices, which consist of new and tried-and-tested hardware. Therefore, there is no need to completely convert all technical equipment into new technologies, which saves the company a lot of time and money.