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Both frontal and side air bags can inflict injuries to the upper extremities in cases where the limb is close to the air bag module at the time of impact. Current dummy limbs show qualitatively correct kinematics under air bag loading, but they lack biofidelity in long bone bending and fracture. Thus, an effective research tool is needed to investigate the injury mechanisms involved in air bag loading and to judge the improvements of new air bag designs. The objective of this study is to create an efficient numerical model that exhibits both correct global kinematics as well as localized tissue deformation and initiation of fracture under various impact conditions. The development of the model includes the creation of a sufficiently accurate finite element mesh, the adaptation of material properties from literature into constitutive models and the definition of kinematic constraints at articular joint locations.

This paper evaluates the biofidelity of the Hybrid III 5th percentile female dummy relative to seven small female cadavers tested as out-of-position drivers in static air bag deployment tests. In the out-of-position tests, the chest was positioned against the air bag module in an effort to recreate a worst-case loading environment for the thorax. Two pre-depowered production air bags and a prototype dual-stage air bag were evaluated. Thoracic accelerometers and chestbands were used to compare chest compression, velocity, acceleration, and Viscous Criteria. A statistical comparison of dummy and cadaver results indicate acceptable biofidelity of the Hybrid III dummy with significant differences observed only in the Viscous Criteria.

Computer simulations and experimental tests were used to examine the effect of humerus orientation on upper extremity interaction with a deploying airbag. The Articulated Total Body program was used to simulate testing of three upper extremity positions ranging from 0° to 90° abduction. Results indicated little difference in peak forearm bending moment for the three positions, a finding which was confirmed with experimental tests of airbag deployment into an SAE 5th % female dummy arm in the 0= and 90= positions. A comparison of simulation and dummy testing with experiments run using cadavers resulted in the conclusion that forearm position, not humerus orientation, plays a critical role in determining upper extremity injury during airbag deployment. Thus, both 0= and 90= abduction tests were found to be valid methods for studying arm/airbag interaction while preserving the rest of the cadaver for future testing.