An experimental air bag test system for the study of air bag deployment Loads

Abstract

An Air Bag Test System (ATS) to study air bag-occupant interactions during close proximity deployment has been developed as a research tool to experimentally simulate controllable and repeatable air bag deployments against targets with various standoff distances. The ATS was calibrated to replicate target response to an arbitrarily selected commercially-available air bag inflator type. A mathematical model was developed to describe the ATS deployment with favourable validation. The model follows an integral approach that treats the unfolding of the bag during deployment as a uniform thinning surface with specified volume-area functions. The model was used to explain the experimental data and provide insight into the energy partition during a deployment including the effects of varying inflator temperature and vent holes on target contact load. The ATS and the model were used to generate benchmark data for computational model and code development validations. One air bag type was studied giving results that are extendable to a wide variety of fleet air bags. Results provided insights on the effects of inflation energy and mass flow on target response. They show that only a very small fraction (3%) of the total deployment energy is delivered to a target. while 60% is stored in the air bag. For a sealed bag, the target response is independent of inflator temperature if the total energy is held constant. Venting reduces the target load primarily during the final pressurization (membrane) phase. For a vented bag, the target velocity decreases with higher inflator temperature.