Study On Airbag Parameters Optimization Method Based On Sled Tests

With the development of china economy, living standard continuously improving and rapidly requiring of automobile demand, national automobile have a break forth developed. but traffic accidents also increased so much. which caused human dies increased year and year. Therefore the costumer's requirements focus on safety performance rather than cheap price. At the same time national vehicle impact standard continuously improved and C-NCAP began to perform which shows that china also focus on the vehicle safety performance. So the automobile manufacture pay much attention to safety performance during there car resign. Almost every type of car installs airbag system. From another point of view, airbag became the important part of the automobile. It not only meets automobile impact regulation but also enhances the improvement of entire security performance. At the same time the passengers have been well protected and the car also has the advantage sales point. Therefore the airbag developed rapidly in this section, airbag match technique also obtained at the same time.The airbag development is inseparable from real car crash tests. After the calibration work of ECU which based on the baseline tests, it needs to optimize the parameter of airbag and inflator and so on. However simulation can decreased the test number in some extent, but repeated validation crash test was still essential. Crash tests need real car and it can not repeat. So the cost is very high. Using white car body,installed the necessary structure (such as the dashboard assembly, in use of panels, steering column and pedal), simulated the real condition of crash vehicle. Using the B-pillar data of real vehicle crash tests as a conference, such a slip test model structures is ready. Use this model to replace the real vehicle, and carry out the repeatable test, the airbag can be optimized, Sled test has a very important significance: it reduced the number of crash tests, reduced development costs and shorted development cycles and verified components performance (seats and seat belts, etc.).There are many sled test equipment developers, although the ultimate target is the same, but the methods are various. So the sled methods are different because of the different equipments. Airbag manufacturers have their own sled test methods according to the characteristics of their own equipments. Test methods are technical secrets in each company and there is no detailed standard at present, according to the different ability of the company, the level of sled tests is also different. Especially for the side sled method, there has no real formal method yet. For the frontal airbag sled simulation, the current view is the same, the sled method also the same, only some differences in details; But for the side impact sled simulation, Europe and the United States have different point of view about side impact injury: The United States believe that the acceleration that caused by the door intrusion affect to the passenger is the main reason to cause the passenger injury during the side impact. But the European think that the door intrusion speed is the main reason that caused the passenger injury. Therefore the sled methods are quite different. Our regulations are based on European standards, so we conduct the sled according to the European model.In fact, airbag optimization process is the adjustment of the airbag protection area and airbag stiffness properties. The key parameter which can influence the airbag performance most is airbag structure and inflator parameter. The adjustment of inflator parameters will bring a series of problems to purchase and production. In order to save cost, normally we adjust the airbag parameters rather than inflator parameters. Unless the available inflator parameters really can not meet for the test requirements, we wouldn't change it. Sled test is a very complicated process and there are so many parameters which can affect the test result, such as: dummy position, seat belts, seats, steering column, steering wheel, brake pedal, and so on. So sled test preparation process is very important. The data analysis is no meaning if the test conditions are not the same. So we can only analysis the test data in the same test platform. In order to conduct the relationship with real car, all tests conditions should be similar with the real vehicle conditions, which is the main reason why we use the real car white body. Even so, the result of sled test can not replace the real car crash test, as the sled is only a simulation process. Because current sled system can not simulate the firewall and steering column movement and pick which caused by the real car crash test, and also to simulate the real car B pillar data itself is an equal process,there are still some tolerance . So it can not achieve the exact condition of the car. The main meaning of the sled is: it can simulate the optimize trend of the vehicle. In other words, the sled test results can not instead of the real vehicle test result, but the optimization trend of sled is nearly the same with that of real car. The level of equipment ability and methods will directly influence the relationship of sled and real car. Through a lot of test experience I had found a proper way to optimize the airbag system based on sled. This method not only establishes a unified experimental test process, but also includes a general data analysis approach. There is a good application. More than 10 vehicle matching tests have been completed. Sled test can bring out enormous economic benefits and strong supply to the passive safety system. Even have good sled equipment but without good sled test method, it can not only affect the test efficiency which can cause the big waste of time, but also get the wrong results, or even mislead the engineer's simulation and design. Therefore it will bring about a tremendous waste of resources, so the r e s e a r c h o f s l e d t e s t m e t h o d s i s a l s o v e r y i m p o r t a n t .