Evaluation of parameters affecting simulation of airbag deployment and interaction with occupants

The current research efforts in airbag modeling are focused on improving airbag deployment and interaction with an out-of-position occupant. This is especially important when other than direct frontal impact is of concern. Thus, the airbag deployment models must address the gas flow dynamics, airbag unfolding and fabric characteristics. This paper discusses the existing capabilities in this field and compares the effect of including gas dynamic details such as inflator jet and airbag unfolding on the deployment predictions. The airbag deployment is simulated using a dynamic model in LS-DYNA3D interacting with a rigid body for 4 different configurations. The simulations were performed on a Silicon Graphics Power Challenge-XL with 10 parallel processors. The analysis shows that the deploying bag may have a much reduced interaction with an occupant positioned oblique to the axis of bag deployment. The inclusion of the inflator jet momentum reveals that it may increase the forces imparted on the occupant and, similar to no jet effects, the distance between the airbag compartment and occupant is a major factor. The result of model prediction are compared with data obtained from motion analysis of a deploying airbag. The volume and geometry of the bag are well-predicted, however, the jet effect may have been somewhat damped, when compared to test results, due to the folding pattern being simulated. This points out the need for further examination of the effect of folding patterns on airbag deployment.