Computer Simulation of Static Deployment Tests for Airbags, Air Permeability of Uncoated Fabrics and Steady State Measurements of the Rate of Volume Flow Through Airbags

A computer program for the simulation of static deployment tests of airbags is introduced. The main output of the program is the pressure vs. time characteristic in the airbag. It also can be used for fine-tuning of the bag in accordance with the inflator characteristic by varying venthole area and fabric properties. This goes particularly for switching from coated to uncoated fabrics.

The mass of gas, energy, temperature, and pressure is calculated at every time using the basic gas dynamic equations, inflator characteristic, seam leakage rate, opening pressure for the cover, fabric stretch, and suction of outside air into the bag. Special attention is given to the properties of uncoated fabrics.

The air permeability of uncoated fabrics has been investigated extensively including the influence of thermal ageing. Some results of these tests are presented here in combination with steady state measurements of volume flow through airbags.