Small Female Upper Extremity Interaction with a Deploying Side Air Bag

This study characterizes the interaction between a small female upper extremity and a deploying side air bag. Results are based on 12 tests with small female cadavers, and 15 tests with the instrumented SAE 5th percentile female upper extremity attached to the 5th percentile Hybrid III dummy. The upper extremity was loaded by a deploying seat mounted thoracic side air bag in a static test environment. Three types of inflators were used varying in peak pressure and pressure onset rate. Three upper extremity positions were chosen that maximized loading to the humerus and elbow joint. Upper extremity instrumentation for the tests included accelerometers and angular rate sensors. Strain gage rosettes were also used on the cadaver anterior and posterior humerus. The SAE 5th percentile female instrumented upper extremity included 6 axis load cells in both the forearm and humerus. Peak humerus moments were calculated for the cadaver tests and compared to the peak humerus moments recorded by the dummy in similar positions. The moments recorded in the cadaver and dummy were similar, despite kinematic differences. Chondral and osteochondral fractures in the elbow joint were recorded for 7 of 12 cadaver tests, while a simple fracture of the distal humerus head was observed in 1 test. Linear regression was performed to correlate occurrence of recorded injury and test parameters. Injury risk functions were constructed for age, forearm acceleration, elbow moment, and air bag inflator level. The dynamic injury tolerance for the 5th percentile female humerus of 128 Nm was recommended for use with the dummy.