The dummies: stand-ins in all size and weight categories

Sep 26, 2019
Stuttgart/Sindelfingen

They have one of the toughest jobs in the car industry: dummies sit in the vehicles during crash testing as stand-ins for human road users. The test dummies are elaborately designed to approximate people as closely as possible and cost up to several hundred thousands euros a piece. The TFS of Mercedes-Benz is home to around 120 crash test dummies. With the new crash test centre, Mercedes-Benz has changed over to digital in-dummy measuring technology. The advantage is that compact data lines have replaced thick bundles of cables.

More powerful sensors, faster and more extensive data collection, better biomechanics – dummies have also seen quite a bit of advancement in recent years. Some 120 dummies are waiting for their turn at the TFS. There are dummies that represent men, women and children, in different size and weight levels, for head-on, rear-end or side impacts. The various dummy types are prescribed by law. Their particular clothing is also precisely defined to ensure the conditions in all crash facilities of the world are uniform and the results are comparable.

The life-size mannequins are chock full of measuring technology that is able to measure acceleration values, distances and forces. A dummy can be fitted with up to 220 measuring points.

The TFS houses certification test benches for all current dummy types. Certification in this context means that the reliable functioning of the mechanical systems is verified and necessary maintenance can be performed on site. The latest dummy models represented in the TFS include

  • THOR (Test Device for Human Occupant Restraint). This model will replace the H3 dummy (Hybrid III) both in the USA as well as in Europe in the coming years. The H3 family was presented for head-on collisions already back in the late '70s and has since been further advanced. All in all, THOR has a much higher biofidelity, meaning it comes closer to the actual behaviour of the human body than its predecessor.
  • World SID (Worldwide Harmonized Side Impact Dummy). It features two superimposed layers of thorax rings and crumple zones at the shoulder. I
  • Q dummies. These are child dummies, available in sizes Q0 to Q10, which model a 50th percentile baby or child of the particular age[1].

Different sizes are also taken into account for the adults. For example, the five-percent woman: Statistically, only five percent of women in the world supposedly are smaller or lighter than this dummy for head-on impacts.

While thick and stiff bundles of cables previously protruded from the dummies and the heavy mannequins could only be put in their intended positions in the vehicles with great effort, today there is only one cable coming out of them. The crash test preparations go accordingly more quickly. In addition to the reliability and the data quality, the advantages of the "in-dummy measuring technology" are less use of space and greater flexibility of the cables. This involves converting the analogue measuring data recorded during the crash test into digital signals and sending them to a central data recorder via a BUS system. The data can then be transferred for the analysis of the crash by means of a system cable.

In medical statistics,[1] the percentile is a measure of the scattering of a statistical distribution sorted by rank or order of magnitude of the individual values. For example, if the body size of a 12-month-old child is in the 10th percentile, this means that 90% of the children of that same age and sex are bigger and 10% are smaller.

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