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Investigation of retrofitted belt attachment points

Kim Marschall completed his bachelor’s thesis for his degree in automotive engineering at the HTW Berlin in spring 2016. The advertised topic of his thesis: “Investigation of retrofitted seat belt attachment points”. An earlier research project by an HTW graduate was to create a list of requirements for the retrofitting of seat belts in vintage cars. This work by Remon Hirsekorn, which you can find on our website under Retrofitting seat belts, was the starting point for Kim Marschall’s bachelor’s thesis.

The Automotive Engineering course at the HTW Berlin conducts a vehicle crash once or twice a year in collaboration with the TU Berlin. This involves verifying the students’ constructive ideas in an experiment. After Remon Hirsekorn’s work, it was obvious to verify his results using a crash test. This was now Kim Marschall’s task.

This crash took place on December 18, 2015. A 1987 Opel Ascona C was driven at 50 km/h without braking into a rigid obstacle. The Opel was chosen because it already had original three-point automatic seat belts at the front and back. Four dummies were sitting in the car, strapped in on the right side of the vehicle with the original black seat belts and on the left side with the orange belts that were installed according to Remon Hirsekorn. The crash was intended to prove that the subsequently installed belts are just as stable as the original belts from the car manufacturer.

Die Bachelorarbeit von Herrn Marschall können Sie hier herunterladen (ca. 18,5 MB).

The crash was sponsored by TÜV Rheinland, the HTW, the company Mansch Fahrzeugteile Berlin and the Atelier Automobile GmbH and a reporter from Oldtimer Praxis was present at the test.

The detailed analysis of the crash was completed in February 2016 and Mr. Marschall was able to complete his bachelor’s thesis, which you can download here, in March. The subsequently installed orange belts not only held as expected, they even held better than the original belts from 1987. In the videos you can see that the original belt on the front right only held after the dummy had already moved forwards by around 30cm. The retractor in the belt reel reacted too slowly. This raises the question of whether seat belts should not be replaced after a certain period of time! So we already have a topic for another thesis.

As can be clearly seen in the videos, the belts held well, but the structure of the 28-year-old Opel Ascona literally collapsed and the front dummies were completely crushed. The dummy in the front right even hit its head on the bonnet. The doors were removed to better film the behavior of the belts, but this alone does not explain the complete collapse of the body. Rather, the body has probably become soft over 28 years and the sheet metal of the door sills, although outwardly fine, has been weakened too much by corrosion. The two front dummies are so crushed that they had to be cut out of the vehicle during a fire brigade exercise in February 2016.

In any case, the subsequently installed belts held and the test can therefore be considered positive. This means that the installation instructions for subsequent seat belts developed by Remon Hirsekorn could be positively verified!

https://youtu.be/2gZ8Kdhy2k4
https://youtu.be/uWF-jnMc3RQ
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