Numerical Simulation Of Airbag Deployment Based On Fluid-Structure Interaction Methodology

Airbag is extensively applied in military, aeronautics, ship, motor and other fields. Due to its transforming ability, its energy-absorption is applied to chariot, air-drop of large-scale and expensive appliance, ship up to slipway and launching; While its floating feature is applied in the water air force-landing, salvage of wrecked ships, etc. The research on airbag is based on a lot of experiments, however, the experiment investment is too much and long-term cycle, and the experimental result is not ideal. With the rapid development of calculation of hardware and software technology, we can use numerical simulation as a replacement. The low costing and short-term cycle as well as the reusability cater to all research fields. Presently, the numerical simulation of airbag mainly uses thermodynamics-based CV(Control Volume) approach. In spite of its quick calculation and not too bad results, it's not proper in the accurate simulation of airbag deployment, especially in the beginning stage. Therefore, we can adopt ALE(Arbitrary Lagrangian Eulerian) of fluid-structure interaction methodology taking into account the interaction of high speed fluid and airbag fabric.Speaking of airbag, people are more familiar with its application in car riding. Thus, this thesis has a resort to car-airbag and explicit finite element program LS-DYNA to develop the research and simulation. This thesis firstly gives a regular meshing method for folded airbag, then introduces the finite-element model-building process of complicated 3-D shaped airbag. In order to verify the reliability and accuracy of mass flow of inflator providing gas for airbag inflation, CV and ALE methods are respectively used to proceed the Tanktest calculation. The result of ALE method shows that it is totally accordance with the expectation, and also validates the correctness of ALE. Subsequently, this method is applied to two kinds of car-airbags and also shows it's perfect.Finally, the method of the car-airbag deployment is applied in an underwater airbag. The airbag inflation uses CV method and the interaction between water and airbag is calculated by ALE method. This thesis simulates both sole airbag and weight-carrying airbag situations.