Automobile Occupant Restraint System Modeling And Performance Optimization In Side Impact

The traffic accident has become a potential dangerous factor to human life safety. So,the vehicle safety takes more attention than before. Some developed countries, such asEurope, America and Japan, have made remarkable achievements in vehicle passive safetyfiled. Occupants are not fatally injured even if vehicle is destroyed. Compared withdeveloped countries, the great disparity still exists though China has made obviousprogresss in vehicle safety filed.In China, the crossing is the major pattern of urban traffic road, so the occurrenceprobability of side impact accident is the highest. Because of the side structure’s weakdeformation endurance and narrow living space, the injury to passengers would be verysevere. Based on a lot of literature concerned, this paper summarizes the research contents,optimization methods and the newest trends in side impact field. It researched andanalyzed the knowledge of occupants’ injury biomechanics and introduced injuryevaluation indexes in side impact. This paper also compared the similarities anddifferences of European and American technical regulations in side impact, and mainlyintroduced the test forms of Chinese New Car Assessment Program(C-NCAP).According to C-NCAP rules, the full vehicle analysis (FVA) model of side impact ofone homemade car was established and the car crash deformation was calculated by usingLS-DYNA. After this, the substructure model of Occupant Restraint System (ORS) wascreated in MADYMO. All of these simulation models were validated by comparing withthe results of real tests. Based on the effecitve substructure model, the performance of ORSwas optimized and analyzed to reduce occupant injury. Firstly, based on the contactmodeling theory, the substructure model was established by using Prescribed StructureMotion (PSM) method and then it was calculated to obtain injury parameters bypositioning ES-2dummy model. Using orthogonal design of experiment (DOE) method,the trim stiffness was optimized. Secondly, the paper researched and analyzed the modeling theory and method of side airbag. The accurate side airbag model was createdand then integrated into the substructure model. Combined with uniform DOE method, theartificial neural network model of ORS was established. And then the design optimizationparameters were found by using Genetic Algorithm (GA) and their reliability was alsoevaluated. Finally, the vehicle side impact ORS multi-body model was established forshortening CPU time in order to study the protection effects of dual-class-inflator airbagsystem to different occupants. Through comparison and analysis of simulation results, thegeneral knowledge was obtained that how the output parameters of dual-class inflatorinfluence occupant injury trend.The research results show that:(a) The optimization of trim stiffness is mainly toreduce occupant abdomen force and pelvis force. It is difficult to improve occupants’chestinjury.(b) Side airbag is the effective auxiliary device to protect occupants from beinginjured in side impact. Through rational matching, the overall injury of occupants can befurther reduced by about20%.(c) In the condition of same crash strength, it is not aneffective way to improve the performance of ORS by using dual-class-inflator airbagsystem in side impact.