Text: by Hiro Saitoh, Bengt Pipkorn and Nils Lubbe
The study had two objectives. The first objective was to provide further evidence for the ability of the tanθBTP (the tangent of the Belt-To-Pelvis angle (the lap belt penetration from the anterior superior iliac spine in the abdominal direction), a geometry-based submarining predictor) to assess submarining risk in a frontal crash for a reclined occupant - a seating position likely to be found in vehicles equipped with ADS (Automated Driving Systems). The second objective was to use the tanθBTP to evaluate the ability of a split buckle system and an anti-submarining seatbelt system with dynamic anchorage repositioning to reduce submarining risks. The evaluation was performed by FE HBM simulation, using a small female HBM and an average male HBM in a reclined posture.
It was shown that the tangent of the Belt-to-Pelvis angle is indeed a useful geometry-based submarining predictor. Secondly, it was demonstrated that both the split buckle belt system and the anchor moving system reduce submarining risks, as predicted by the tangent of the Belt-to-Pelvis angle. ADS vehicles should be equipped with these or similar advanced anti-submarining technologies, a potential business for Autoliv.
Anti-submarining seatbelt system with dynamic anchorage repositioning. The movement of the anchor position started 10 ms after the collision and lasted 20 ms after the collision. The amount of movement was set to 75 mm in both the forward and downward directions.
![](https://www.autoliv.com/sites/default/files/2022-05/SAE4b.png)