Interaction of the Hybrid III Femur and Pelvis - A Mechanical Analysis

In air bag tests without a restraining seat belt (FMVSS208) several users of the Hybrid III dummy have reported a pelvic interference problem during the tests. An insufficient range of motion and a hard metal to metal contact between the pelvis and femur has lead to unexpected chest acceleration waveforms.

The paper gives a mechanical analysis of this phenomenon, explaining how the forces acting on the dummy lead to a rotation of the pelvis and femur and how forces arise between the pelvis and the chest. Finally two sample tests where the pelvic interference problem has occurred are presented.