A Lagrangian fluid–structure interaction approach for the simulation of airbag deployment

The numerical simulation of airbags is receiving an increasing attention for the remarkable advantages in terms of cost, efficiency, flexibility and amount of data that can be extracted from the analysis. This work proposes an advanced fluid–structure interaction (FSI) numerical technique for the simulation of airbag deployment. The fluid subproblem, described by weakly compressible Navier–Stokes equations, is solved exploiting the advanced features of the Particle Finite Element Method (PFEM) while the solid subproblem is addressed using standard Finite Element method. A domain decomposition approach with a special treatment of the fluid–structure interface conditions has been implemented to couple fluid and structural solvers allowing for non-conforming meshes at the interface and different time step size in the two subdomains. A peculiar feature of the proposed methodology is the explicit time integration, mandatory for the solution of very fast dynamics problems, like the airbag deployment: an explicit fluid solver is coupled explicitly with an explicit structural solver. The proposed technique is first tested on a inflation of a balloon, showing very good agreements and then it has been applied to the real case of airbag deployment.