Regulations and interventions to protect far-side occupants in crashes do not currently exist, despite these occupants accounting for 43% of the AIS3+ injured persons and 30% of the overall Harm in side impact crashes. Furthermore, no suitable ATDs or mathematical models have been developed to investigate far-side occupant dynamics. The aim of this study was to investigate seat belt to shouldercomplex interaction during the first phase of a farside impact for incorporation into a multibody occupant model.

The model adaptations were derived based on quasistatic belt slip tests using two volunteers, a standard Hybrid III ATD and a Hybrid III Spring-Spine ATD. The model development was validated for this first phase of impact by comparison with shoulder belt force-time histories and head lateral displacements from lateral far-side sled tests using PMHS and a WorldSID ATD.

The newly adapted model correctly predicted seat belt to shoulder complex interaction in all of the quasi-static belt slip tests, compared to 50% and 67% for Hybrid III and Hybrid III Spring-Spine respectively. Furthermore, the model was able to predict the increasing likelihood of the seat belt engaging the shoulder when the D-ring moved rearward and pretension increased. For the validation tests, the magnitude and phasing of the shoulder-belt force-time and head displacement-time histories were generally within 10% of the PMHS results. In addition, the model was capable of predicting the location of occupant to seat belt interaction observed in the PMHS tests.