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In recent years supplemental inflatable restraint systems (airbags) have been installed in motor vehicles to mitigate driver/front passenger harm in vehicle frontal crashes. The performance of the airbag and the level of protection it provides the occupant can be evaluated by a combination of experimental and analytical techniques. Analytical modeling of airbag inflation is desirable in automotive design, particularly when the technique encompasses the airbag, occupant and vehicle structure in an integrated system. This paper is concerned with the development of nonlinear finite element (FE) technology to simulate airbag deployment and its interaction with an articulated occupant model. This technology is being developed in the dynamic large deformation Lagrangian based DYNA3D code which has been successfully used in vehicle crashworthiness simulations. The airbag material was simulated by an orthotropic “wrinkle free” membrane elastic model.

A deformable finite element dummy model was used to simulate air bag interaction with in-position passenger side occupants in frontal vehicle crash. This dummy model closely simulates the Hybrid III hardware with respect to geometry, mass, and material properties. Test data was used to evaluate the validity of the model. The calculated femur loads, chest acceleration and head acceleration were in good agreement with the test data. A semi-rigid dummy model (with rigid chest) was derived from the deformable dummy to improve turnaround time. Simulation results using the semi-rigid dummy model were also in reasonable agreement with the test data. For comparison purpose, simulations were also performed using PAMCVS, a hybrid code which couples the finite element code PAMCRASH with the rigid body occupant code. The deformable dummy model predicted better chest acceleration than the other two models.