Upper extremity interaction with a deploying side airbag: a characterization of elbow joint loading

Area of Science:

• Biomechanics
• Injury Biomechanics
• Automotive Safety

Background:

• Understanding occupant response to side airbag deployment is critical for vehicle safety.
• Previous research has limitations in accurately simulating small female upper extremity kinematics and injury.
• Anthropometric test devices (ATDs) require enhanced biofidelity for realistic injury assessment.

Purpose of the Study:

• To analyze the biomechanical response and injury patterns of the small female upper extremity under side airbag loading.
• To evaluate the biofidelity of a newly developed enhanced upper extremity for the fifth percentile female Hybrid III ATD.
• To identify key force metrics correlated with specific upper extremity injuries.

Main Methods:

• Computer simulations and physical experiments using a new enhanced fifth percentile female Hybrid III ATD and small female cadaver subjects.
• The enhanced ATD upper extremity incorporated a two-axis wrist load cell and forearm pronation capability.
• Instrumentation included accelerometers, angular rate sensors, and multi-axis load cells to measure forces and kinematics.

Main Results:

• Cadaver experiments resulted in severe upper extremity injuries, including humerus, elbow, radius, and carpal bone fractures.
• The enhanced ATD demonstrated improved biofidelity in simulating upper extremity interaction.
• Multivariate logistic regression identified a significant correlation (P=0.05) between elbow axial/shear forces and elbow injuries.

Conclusions:

• Side airbag loading poses a significant risk of severe upper extremity injury to small female occupants.
• The enhanced ATD provides a more biofidelic representation of the small female upper extremity response.
• Forearm load cell data, specifically elbow axial and shear forces, can predict elbow injury risk.