PASSIM-PLUS, A Multi-Element, Passenger Airbag Model 910151
A multi-element passenger side airbag model for analyzing airbags of complex shape is discussed. The model has the capability of allowing the passenger to interact with the three dimensional, instantaneous airbag shape determined by the various contact surfaces encountered by the airbag. Therefore, the shape of the contact surface presented to the passenger is not constant but deformable and can therefore accommodate large deflection penetrations by the passenger. Up to 3000 airbag elements can be used to configure the desired airbag shape.
Airbag mass and its effect on airbag deployment kinematics and the subsequent bagslap forces are taken into account. Because of this, the model is capable of computing the kinematics and resultant injury of forward positioned children as well as normally seated adults.
Because of the multi-element airbag approach, the effect of instantaneous vent blockage of porous airbag materials due to contact with the passenger and vehicle compartment may be taken into account and evaluated.
The model is fully supported by various menu driven pre- and post-processors for treating the input files as well as evaluating the output.
A special, menu driven, interactive pre-processor, structured to receive User input in a format compatible with conventional airbag drawing coordinates and dimensions, facilitates rapid creation of the 3-D airbag “mesh”. Because of this, the multi-element mesh, for even the most complex airbag shapes, may be quickly obtained.
Another pre-processor computes the inflator mass flow and gas temperatures from tank test data.
All FMVSS-208 injury measures are computed and summarized. Post-processors provide full graphic output in curve plot overlay (for comparing test vs. simulation or simulation vs another simulation) and animated kinematic format.
Validation of the model for both the normally seated adult and out-of-position child are included in the discussion. The results show that the model is not only easy to use but also quite accurate in its predictive ability.