Numerical prediction of the structural failure of airbag inflators in the destructive testing phase

The aim of the present numerical study was to predict the structural failure of airbag inflators undergoing destructive bust tests, while accounting for the thermomechanical history of the constitutive material. For this purpose, the material was previously characterized under tension, compression, torsion and shear loading conditions at various strain rates. It was found to be elastic–viscoplastic and prone to ductile fracture. The behaviour of the material was then modelled using the Gurson–Tvergaard–Needleman (GTN) approach, and the material constants were identified via the gradient-based inverse method. The observed and predicted locations of the damage induced by void growth during the crimping process showed good agreement. In addition, the numerical simulations of the destructive testing phase (involving dynamic internal pressure loading) yielded a Mode I-like failure process, as observed experimentally. The burst pressure value predicted was found to be very similar to the experimental value, which confirms that the conservative method presented here could be usefully applied to industrial situations.