Development and Correlation Of a Simplified Mathematical Model Able to Forecast Impact Damping Provided By a Driver Airbag

Dozens of new vehicles models are launched annually, each of them requires the development or at least the calibration of a new occupant restraint system (ORS), driver airbag is part of this system. At the same time, consumers have become increasingly aware about vehicle safety performance and high safety parameter became a competitive factor for automakers. The development, optimization, and validation of ORS is a complex and expensive process. Thus, numerical simulation is essential in the initial and intermediate stages of airbag development to minimize time and cost associated with experimental testing. In general, virtual simulations applied in automotive industry requires considerable computational effort, simulation time and often skilled labor to deal with complex solvers. Thus, due to the increasing need to evaluate airbags behavior quickly and with low cost, this work aims to develop a model able to describe in a satisfactory way the interaction between an airbag driver and the occupant applying concepts from classical mechanics. The model was implemented in MATLAB language so that the results could be obtained quickly and efficiently through the iterative method. Some considerations have been made to simplify the phenomenon: the gas inside the airbag was considered an ideal gas, it was assumed that the airbag is symmetrical and all the deformations suffered by it are also spread symmetrically, the gas compression inside the cushion occurs adiabatically and the temperature profile inside of it is uniform. The developed model was correlated with Zhang et al model with less than 6% deviation, showing it was efficient to forecast the airbag behavior. In order to improve model correlation it is recommended to perform physical tests and compare the results with the developed model.