Low Risk Deployment Airbag Module Research

U.S. National Highway Traffic Safety Administration believes that the airbagdeployment testing standard should be different respectively to1-year-old,3-year-old,6years old, and5%women, and the testing standards also different when passengersare beyond the normal body shape and weight of adult passengers. There are3regulation strategies provided for vehicle manufacturers to choose: static (occupantclassification) airbags close; dynamic (the occupant position) airbag off; low riskdeployment. With more and more market demand and implementation requirementsfor regulatory status, the development of a low-cost airbags with high service lifestructure becomes a possibility, especially the use of low-risk deployment strategiesthat can protect the adult occupant both with seatbelt and without seatbelt, but also canprotect the occupant from the5th to the95th, also minimize the injury to children andOOP occupant.The author release a low risk to expand the airbag device with a module bracket,there are inflator and cushion (with tether) on the module bracket, and the bracketequipped with a tether locking device. Performance of the airbag structure can balancethe normal position better and supply better constraint for OOP state: supply a lessinflatable shallow airbag to front seat passenger; supply a inflatable enough deepairbag to rear seat passenger.The author using Arbitrary Lagrangian-Eulerian method (ALE) supplied byLS-DYNA directly calculate the gas flow from inflator and establish the dependencyrelation between the gas flow and the air bag (folding). Application of the ALE methodis a good way for simulating airbag deployed state in the first few milliseconds,because this method can be obtained a more accurate result than UP method. Usingthis approach simulates OOP problem in initial stage. Model change (in a small range)can be performed and evaluated, but the simulation results often need to validate bytest. With the capability improvement of CPU (dual-core, multi-core), this approachwill get more and more accurate results compared to UP method.This paper researches an experimental method that uses linear collision on apassenger side air bag module. Its advantage is that can repeat tests, and more realisticthan other module test environment. It provides a standard device to compare airbagimportant parameters: early stage energy absorption of the airbag module, the peak acceleration position and value, and the maximum offset value.In the sled test Simulation, low-risk deployment airbag system meet all testingconditions in0°and in the normal position, as well as comply with the testingconditions of95th dummy without seatbelt (25mph) and5th dummy with seatbelt(35mph) in the future. Under the normal position testing condition, design the rightangle collision to50th dummy without seatbelt. Before we attempted to use anexperiential and usual airbag with two-stage inflator to this condition, the results werenot successful. Using Low risk deployment airbag to do sled test, then conducted abarrier crash test, the result was successful. Using10years child ATD (projectobjectives), the first level of the thickness of the cushion deployed, successfully metthe test of NHTSAOOP position1and position2. However, during the deployment ofthe second stage thickness of the cushion, the OOP test result exceeded the target value.It may be necessary to improve OOP performance and assist design balance and adjustoccupant performance. Because the adjustability of low risk deployment airbag innormal position, this study get an acceptable normal position performance, and didn’tpresent obvious compromise on OOP performance.