Meshing and Folding

The airbag fabric should be meshed in the non-folded state using tria elements with an average element size of 3 to 4mm. Mixed + tria mesh is allowed starting in version 2021.2. Larger element sizes are only acceptable for vent holes and other components that use a void material (example, inter-chamber void component). All nodes of void related elements should be attached to the surrounding fabric components. Airbag fabrics have a low modulus of elasticity and therefore normally the elements size does not affect time step.

External airbag fabric components should form a closed volume with normal vectors directed outwards.
Note: This limitation was released in version 2021, but it is still recommended to have outward normal.

Intersections between any airbag components (for example, external, internal, inflator, or housing) are not allowed.

Airbag folding should be performed using pre-simulation according to the CAD folding design. The folding model should use validated fabric material definitions and contacts. Radioss is the preferred solver for pre-simulation folding (Airbag Solutions). This guarantees that the folded model will work correctly with the airbag internal contact definition listed in corresponding sections.