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This paper presents a parametric study that utilized the CVS/ATB multi-body simulation program to investigate the interaction of the hand and wrist with a door handgrip during side air bag loading. The goal was to quantify the relative severity of various hand and handgrip positions as a guide in the selection of a test matrix for laboratory testing. The air bag was represented as a multi-body system of ellipsoidal surfaces that were created to simulate a prototype seat-mounted thorax side air bag. All simulations were set in a similar static test environment as used in corresponding dummy and cadaver side air bag testing. The occupant mass and geometric properties were based on a 5th percentile female occupant in order to represent a high-risk segment of the adult population. The upper extremity model consisted of wrist and forearm rotations that were based on human volunteer data.

Computer simulations, dummy experiments with a new enhanced upper extremity, and small female cadaver experiments were used to analyze the small female upper extremity response under side air bag loading. After establishing the initial position, three tests were performed with the 5th percentile female hybrid III dummy, and six experiments with small female cadaver subjects. A new 5th percentile female enhanced upper extremity was developed for the dummy experiments that included a two-axis wrist load cell in addition to the existing six-axis load cells in both the forearm and humerus. Forearm pronation was also included in the new dummy upper extremity to increase the biofidelity of the interaction with the handgrip. Instrumentation for both the cadaver and dummy tests included accelerometers and magnetohydrodynamic angular rate sensors on the forearm, humerus, upper and lower spine.

The purpose of this study was to develop a fracture tolerance for the elbow joint, or proximal ends of the ulna and radius, relative to the fracture risk under side-impact airbag loading. Forty experiments were performed on the elbow joints of small female cadavers. The energy source, a pneumatic impactor, was configured to apply compressive loads that match the onset rate, peak force, and momentum transfer of previously conducted side-impact airbag tests with small female subjects. Three initial orientations of the impact load angle relative to the longitudinal axis of the forearm were selected based on analysis of side-impact airbag tests with the instrumented dummy upper extremity. These included loading directions that are 0°, 20°, and 30° superior of the longitudinal axis of the forearm. Post-test necropsy revealed that 11 of the 40 tests resulted in chondral, osteochondral, or comminuted fractures of the proximal radial head or the distal trochlear notch.