This study investigates the interaction of a deploying air bag with cadaveric upper extremities in a typical driving posture; testing concentrates on female occupants. The investigation goals are to determine the risk of upper extremity injury caused by primary contact with a deploying air bag, and to elucidate the mechanisms of these upper extremity injuries. Five air bags were used that are representative of a wide range of air bag `aggressivities' in the current automobile fleet. Sixteen excised cadaveric upper extremities were mounted to a four degree-of-freedom universal joint that functioned as a shoulder. The results indicate that the air bag/flap interaction may be significant in the production of some injuries, but is not necessary to produce peak moments in the forearm. These primary contact injuries occurred within 13 ms of the deployment near the site of interaction with the flap. Comparison tests were performed with the Society of Automotive Engineers (SAE) 5th Percentile Female Instrumented Arm using four of the air bags tested in the cadaveric series. Repeated tests revealed no significant difference between the forearm response on the fixture and on the dummy. Resulting forearm moments were used to develop logistic injury risk functions for ulna and ulna/radius fractures of female forearms in the worst case position under air bag deployment. (A)
Abstract