Evaluation of the Biofidelity of the BioRID-II and THOR-NT Anthropomorphic Test Devices under Seatbelt Pre-Pretensioner Loading in Stationary Conditions

Conference contribution, 2013

Pre-pretensioners are active and reversible devices that apply light tension to the seatbelt (less than 300N) which pulls road vehicle occupants rearwards and reduce the backset (head-to-head restraint horizontal distance). This action has been found to have the potential to reduce the number of whiplash injuries in rear impacts. However, pre-pretensioners induced a new load case on current Anthropomorphic Test Devices (ATDs) for which they have not been validated. The purpose of this study was to evaluate the biofidelity of two 50th percentile male ATDs (BioRID-II and THOR-NT), under pre-pretensioner loading in a stationary environment. A literature review resulted in three testing positions that either occur frequently (backset exceeding recommendations) or have high injury potential (leaning far forward at the driver and front passenger seats). Experiments comprised six volunteer subjects, the BioRID-II and the THOR-NT. Corridors for the head-neck complex kinematics, and interaction of the subjects with the seatbelt, were generated based on data from the volunteer tests and ATD responses were compared to the corridors in terms of amplitude, peak occurrence and shape. For slight out-of-position cases (backset ~80mm), the THOR-NT was found to be close to relaxed volunteers and the BioRID-II to tense volunteers; both were suitable for pre-pretensioner testing. Although the BioRID-II results were closer to the corridors than the THOR-NT results in the far forward leaning positions, neither showed sufficiently large rearward motions and head rotations to fit the corridors. Furthermore, head rotations were problematic for both ATDs in the three test positions. Therefore, construction changes to both the pelvis and occipital joints are suggested in order to improve the biofidelity of BioRID-II and THOR-NT in far forward leaning positions.