Comparison of the Rear Impact Biofidelity of BioRID II and RID2

Biomechanical responses of PMHS in moderate-speed rear impacts and development of response targets for evaluating the internal and external biofidelity of ATDS

The objectives of this study were to obtain biomechanical responses of post mortem human subjects (PMHS) by subjecting them to two moderate-speed rear impact sled test conditions (8.5g, 17 km/h; 10.5g, 24 km/h) while positioned in an experimental seat system, and to create biomechanical targets for internal and external biofidelity evaluation of rear impact ATDs. The experimental seat was designed to measure external loads on the head restraint (4 load cells), seat back (6 load cells), and seat pan (4 load cells) such that subject dynamic interaction with the seat could be evaluated. This seat system was capable of simulating the dynamic characteristics of modern vehicle seat backs by considering the moment-rotation properties of a typical passenger vehicle, thus providing a more realistic test environment than using a rigid seat with a non-rotating seat back as done in previous studies. Instrumentation used to measure biomechanical responses of the PMHS included both accelerometers and angular rate sensors (ARS). A total of fourteen sled tests using eight PMHS (males 175.8 ± 6.2 cm of stature and 78.4 ± 7.2 kg of weight) provided data sets of seven PMHS for both test conditions. The biomechanical responses are described at both speeds, and cervical spine injuries are documented. Biomechanical targets are also created for internal and external biofidelity evaluation of rear impact anthropomorphic test devices (ATDs).

A. Kim, k.f. Anderson, j. Berliner, j. Hassan, j. Jensen, h.j. Mertz, h. Pietsch, a. Rao, R. Scherer, and a. Sutterfield

In this study, three dummies were evaluated on the component level and as a whole. Their responses were compared with available volunteer and embalmed Post Mortem Human Subject (PMHS) data obtained under similar test conditions to evaluate their biofidelity. The volunteer and PMHS data, used as comparators in this study, were used previously to establish some of the biofidelity requirements of the Hybrid III. The BioRID II, the Hybrid III, and the RID2 were all subjected to rear impact HYGE sled tests with deltaVs of 17 and 28 km/hr to determine their biofidelity in these conditions. A static pull test, where a load was manually applied to the head of each dummy, was used to evaluate the static strength of their necks in flexion and extension. Finally, pendulum tests were conducted with the Hybrid III and RID2 to evaluate the dynamic characteristics of their necks in flexion and extension. The sled test results indicate that out of the three dummies, the overall flexibility of the Hybrid III is comparable to that of the volunteer anticipating the impact. The overall flexibilities of the BioRID II and the RID2 are greater than those of all the comparators used in this study (the tensed volunteer and the two embalmed PMHSs). The responses of the Hybrid III are closer to those of the tensed volunteer than those of the PMHSs. The responses of the BioRID II and the RID2 are closer to those of the PMHSs than to the tensed volunteer.