Evaluation of LS-DYNA® Corpuscular Particle Method for Side Impact Airbag Deployment Applications

A uniform pressure method, i.e. no pressure variation on bag surface and location, in LS-DYNA has been commonly used to simulate airbag deployment and interaction of airbag with the occupants. Another newly developed LS-DYNA CPM (Corpuscular Particle Methodology) has gained recognition and acceptance recently because it considers the effect of transient gas dynamics and thermodynamics by using a particle to represent a set of air or gas molecules and then a set of particles to represent the entire air or gas molecule in the space of interest. This innovative method, however, has yet be fully utilized and applied with confidence in airbag deployments simulation without systematic tests and validations to avoid non-physical tuning factors traditionally being applied to the uniform pressure airbag finite element models. In this paper, inflator closed and vented tank tests, static airbag deployment test, and linear impactor tests with various configurations and impact speeds are systemically conducted and then correlated with a CPM airbag model to determine whether the methodology can be applied for all the tests and whether any tuning factors should be applied in the process. This innovative LS-DYNA particle method has been fully investigated in this systematic study by correlating it with a comprehensive set of inflator tank tests, static airbag deployment, and rigid linear impactor tests. The correlations start from inflator closed and vented tank tests to verify the provided inflator characteristics, mass flow rate and temperature curves. The inflator characteristics will then be employed into static airbag deployment simulation to determine the airbag fabric heat convection coefficient, which is adjusted in this simulation to match the test pressure profile. This is the only parameter tuned to match the test pressure. This airbag model is then used to simulate those linear impact tests. With the systematic validations and correlations to avoid using tuning factors, the airbag model results in a good match of the overall airbag internal pressure and impactor deceleration histories with the tests and the simulations for all the linear impactor tests conducted. Effects of the inflator variations are also studied to illustrate the potential bounds of deceleration and airbag chamber pressure in impacts.