Evaluation of seat protection in low to medium severity rear impacts by means of the BioRID II and double peak crash pulses

Whiplash injuries (AIS 1 neck injuries) are still common in rear impacts, but research has shown the importance of seat design in order to reduce this type of injury. The aim of the study was to evaluate a number of seat configurations to assess the whiplash injury risk at different severities. A total of 21 sled tests were performed with 4 different severities and 5 different seat configurations. The dummy used was the BioRID II. The crash pulse was of the double peak type with either 60 or 120 m/s2 as a maximum. The Delta-V was either 15 or 25 km/h. The results show that seat design and restraint systems have a significant impact on the dummy kinematics in a low to medium severity rear impact. NICmax values between 7 and 35 m2/s2 were produced. Furthermore, upper neck tension forces (Fz) between 180 and 1680 N were produced. Several other parameters were evaluated including the upper neck moment, and head angular acceleration. The result shows that the same Delta-V generated with different pulse shapes can significantly alter the dummy response. Also of importance is that the dummy possibly needs to be more biofidelic in medium severity rear impacts since there is a risk of an artefact in the interaction between the head restraint and the upper back of the dummy. This is likely to be the case for the Hybrid III dummy as well. The anti-whiplash seats included in this study are likely to provide increased protection in low and medium severity rear impacts. A good seat design as determined by the BioRID involves controlled displacement and yielding of the seat above a certain severity in combination with support for the whole spine.