Air Bag Loading on In-Position Hybrid III Dummy Neck

The Hybrid III family of dummies is used to estimate the response of an occupant during a crash. One recent area of interest is the response of the neck during air bag loading. The biomechanical response of the Hybrid III dummy's neck was based on inertial loading during crash events, when the dummy is restrained by a seat belt and/or seat back. Contact loading resulting from an air bag was not considered when the Hybrid III dummy was designed. This paper considers the effect of air bag loading on the 5^th percentile female Hybrid III dummies. The response of the neck is presented in comparison to currently accepted biomechanical corridors.

The Hybrid III dummy neck was designed with primary emphasis on appropriate flexion and extension responses using the corridors proposed by Mertz and Patrick. They formulated the mechanical performance requirements of the neck as the relationship between the moment at the occipital condyles and the rotation of the head relative to the torso. The deformation of the neck was due to the motion of the head relative to torso, when the torso was restrained either by the seat belt or the seat back. Air bag loading is significantly different from belt or seatback loading, because there is more than one load path on the head. During air bag loading, the dummy neck shows significantly different responses from those seen in the Mertz and Patrick tests. The neck experiences second mode bending during air bag loading as opposed to the first mode bending seen in seat belt and/or seat back loading.

The Hybrid III 5^th percentile female dummy is frequently used to estimate the response of small stature occupants to air bags. This paper examines the Hybrid III 5^th percentile female dummy’s neck responses due to air bag loading. The neck responses were found to be highly dependent on how the air bag interacts with the dummy. Three modes of air bag-neck interaction were observed and studied: air bag directly loading the head, air bag trapped under the chin during the deployment process and air bag trapped behind the jaw of the dummy head. This paper also presents the results of some experimental modifications to the head/neck design of the Hybrid III 5^th percentile female dummy to prevent air bag entrapment.