This paper presents the dynamic injury tolerances for the female humerus and forearm derived from dynamic three-point bending tests using 22 female cadaver upper extremities. Twelve female humeri were tested at an average strain rate of 3.7 +- 1.3 strain/second. The strain rates were chosen to be representative of those observed during upper extremity interaction with frontal and side airbags. The average moment to failure when mass scaled for the 5th% female was 128 +- 19 Nm. Using data from the in-situ strain gages during the drop tests and geometrical properties obtained from pre-test computed tomography (CT) scans, an average dynamic elastic modulus for the female humerus was found to be 24.4 +- 3.9 GPa. The injury tolerance for the forearm was determined from 10 female forearms tested at an average strain rate of 3.94 +- 2.0 strain/second. Using three matched forearm pairs, it was determined that the forearm is 21% stronger in the supinated position, 91+- 5 Nm, versus the pronated position, 75 +- 7 Nm. Two distinct fracture patterns were seen for the pronated and supinated groups. To produce a conservative injury criterion, a total of 7 female forearms were tested in the pronated position, which resulted in the forearm injury criterion of 58 +- 12 Nm when scaled for the 5th% female. It is anticipated that this data will provide injury reference values for the female forearm during driver air bag loading, and the female humerus during side air bag loading. (A)
Abstract