A series of 7 rear impact sled tests, having a nominal delta V (speed change) of 21 mph, with Hybrid III dummies positioned in the "Normal Dummy Seated Position", "Out of Position" and slightly "Out of Position" is presented. Tests were performed on yielding production Toyota and Mercedes Benz seats and on a much stiffer modified Ford Aerostar seat. Available Hybrid III upper and lower neck and torso instrumentation were used to analyze and to compare injury potential for each set of test parameters. In all cases, neck forces and moments were found to increase when the dummy's torso was leaned forward at impact. For the out-of-position tests, the results showed that the upper neck loads were clearly related to seat loads were clearly related to seat stiffness; stiffer seats produced greater neck loading. The lower neck loads, however, showed no definite correlation with seat back stiffness.
Abstract