Study of the kinematics of the THOR dummy in nearside oblique impacts

Abstract

Oblique and small-overlap crashes are the second most common frontal crash type leading to fatal outcome. This study discusses a simplified test rig suitable to analyse the performance of the THOR dummy in oblique impacts. Secondly, this paper compares the kinematics and dynamics of the THOR dummy under the loading of two types of seat belts. Last, the study compares the response of the THOR finite element (FE) model to the one of the physical dummy. By means of mathematical simulations with the THOR FE model different seat designs were evaluated so that the dummy kinematics could approximate those observed in real vehicles. Thereafter two different three-point seat belt systems were evaluated via physical and computer-modelled sled tests: a pretensioned (shoulder retractor and lap) force-limiting seat belt (reference seat belt) and an innovative belt in which the shoulder and the lap bands were split (split buckle). The study shows that THOR pelvic displacement was significantly reduced in a realistic manner by using a modified angled seat in comparison to the originally flat seat of the test fixture. The THOR dummy was able to discriminate between the two seat belt systems and the results suggest that the split buckle restraint has the potential to achieve significant injury reducing benefits in the oblique loading condition. In the comparison of the THOR mathematical and mechanical models, a total CORA score of 0.62 was obtained for the reference seat belt comparison and a score of 0.60 was obtained for the split buckle comparison.