Comparison of upper extremity test devices for the evaluation of frontal air bags

Abstract

This study examines the response of two upper extremity test devices under driver-side air bag deployment to contribute to the development of dummy surrogates for the investigation of primary contact forearm injuries during air bag deployments. The first of these test devices, the SAE 5th Percentile Female Arm (SAE arm), is an anthropomorphic representation of a small female forearm and upper arm that is instrumented with load cells, accelerometers and potentiometers to enable the determination of upper extremity kinematics and dynamics. The second, the Research Arm Injury Device (RAID), is a simple beam test device designed for detailed investigation of moments and accelerations resulting from close contact in the initial stages of air bag deployment. It includes strain gauges distributed along its length to measure the distribution of moment applied by the air bag deployment. The study used four air bags representing a wide range of aggressivities in the current automobile fleet. Logistic risk functions for forearm fracture were developed using existing cadaver studies and the moment response of each test device. These risk functions indicate that, for 50 per cent risk of ulna or ulna/radius fractures, the SAE arm peak forearm moment is 67 N m while the RAID peak forearm moment is 373 N m.