Calculation of the volume of a airbag using the finite element method

The volume of an automotive airbag is one of important factors which may affect, gas flow characteristics of the airbag. A total Lagrangian formulation and the wrinkling scheme introduced by Kang and 1m are used in a geometrically nonlinear finite element analysis for calculating the volume of the airbag of which fabric is modeled as an orthotropic material. The wrinkling scheme enables us to update the stress and the internal forces correctly taking into account the existence of wrinkling. Numerical results of the volume calculation are given via the example of the quasi-static inflation of an circular airbag.