This study was undertaken to develop new passenger side Advanced Adaptive Restraint Systems to better protect automobile passenger occupants from serious injuries in frontal and oblique motor vehicle crashes.

New concept designs of a passenger airbag and a knee airbag, each with controllable dual-volume and tunable vents, were developed. A new advanced adaptive restraint system, integrated with such developed passenger airbag, knee airbag and an updated seatbelt system consisting of a switchable dual-load limiter retractor with shoulder and lap pretensioners, was optimized to achieve good performance for all the fourteen load cases defined in this study

The fourteen load cases represent various real-world crash scenarios comprising passengers of three body sizes seated at different seating positions (the small-size female at full-forward, mid-track, and full-rearward, the mid-size and large-size males at mid-track and full-rearward) under a “hard” pulses representing the 35mph full frontal and frontal oblique crashes of a sub-compact passenger car. The system performances were evaluated with the two sets of occupant injury assessment tools:​ 1) the Anthropomorphic Test Devices (ATDs) of the three body sizes (the Hybrid-III 5 th %ile female dummy, the THOR 50 th %ile mid-size male dummy and the Hybrid-III 95 th %ile large-size male dummy) with the injury risk functions used in current regulatory lab tests, and 2) the full body Human Models (HMs) of the three body sizes (the 5 th %ile female model F05-O v3.1, the 50 th %ile male model M50-O v4.5 and the 95 th %ile male model M95-O v1.2) developed by Global Human Body Model Consortium (GHBMC)) with the published injury risk functions derived from the Postmortem Human Subject (PMHS) tests. For each load case, four passenger side sled system models were developed, paired with the ATD and the HM of the same size, and for the current production restraints (baseline) as well as the new restraint designs. The injury risks of the occupant body regions and combined injury risks (referred to “Occupant Injury Measures”) were estimated with both ATDs and HMs.

The new adaptive restraint system design was developed through individualized optimization for all the fourteen cases in multiple iterative steps. Firstly, the new concept designs were made at the component level, evaluated using two validated ATD sled test models simulating the two load cases (5 th %ile female at full- forward position and 50 th %ile male in full-rearward position). Secondly, the new advanced adaptive restraint system was optimized with the ATDs in seven successive steps, obtained the optimal restraint design parameters set for each load case. And finally, the optimal adaptive restraint configuration for each case was verified with the HMs sled models. Hundreds of the sled simulations were performed in such processes.

The results demonstrated that the new adaptive passenger restraint system design has more versatile adaptivity and improved performances for all the considered load cases than the baseline restraints. The benefits for the occupant injury risks reduction vary case by case, within 12%-79% margin estimated with the ATDs and 8%- 66% with the HMs.