| The vehicle side impact collision is one of the most common types in fatal crashes. It includes car-to-car side impact and car-to-narrow object collision. In real traffic accidents, side impact of passenger cars with fixed pole, as a special type of side impact, may result in severe injuries to the occupants, so it is necessary to study the collision of pole side impact. In order to improve the side pole impact crashworthiness, the car side structure, as an important assembly of passenger car side configuration, is the main component to withstand the impact force in side collision. Its intrusion, intrusion velocity and deformation mode are main causations of occupants injuries. So the ideal match of side components in the car can effectively reduced the injury risk of occupants in side pole impact.Based on the side pole impact, the study adopts the surrogate model theory, the relevant optimization method and the crash simulation software to bring out the optimization method and process for automotive carsh safety. At the same time, the protection of occupant's chest is enhanced by controlling the car accerlaration and B-pillar intrusion in the level of the chest region of occupants normally seated in the vehicle in side pole impact.Firstly, the paper analyzed the the vehicle dynamic response and occupant response characters in actual impact based on the theory of car collision simulation and human injury mechanism. According to the latest Euro-NCAP regulations, a finite element model of pole side impact was developed and validated, and then an assessment was briefly made on its safety performance. After the car's side structure has been improved by using theoretical mechanic method, a comparative analysis was carried out between the former and latter model in terms of the side structure deformation, acceleration response and system-energy response of the car body, and further revealed the pole side collision characteristics.Furthermore, the material of side components was defined as design variable and the vehicle lateral accerlaration and B-pillar maximum intrusion as the two main targets for evaluation. Based on the structure-improved model, the sensitivity analysis betweeen the design variables and targets was assessed with the help of orthogonal experimental design and comprehensive equilibrium methods. Then the optimal match of material was selected and in order to optimize the thickness of side structure, the Kriging surrogate model was established by using Latin-hypercube design methodology to provide the Kriging approximation with experimental samples. At last, the Kriging functions were optimized by multi-objective genetic algorithm (GA) to get the final optimal results.The results of the research show that the most effective measures to improve the crashworthiness of mature body structure is the reasonable matching of stiffness and strength which doesn't affect the original function of parts; Applying the approximate model to the crashworthiness optimization of vehicle in pole side impact configuration is feasible and efficient, simultaneously increasing computing efficiency and saving the production cost; The material matching and thickness optimizing of side components can effectively control the vehicle accerlaration and decrease side intrusion, improving the car's crashworthiness and reducing occupant injury risk. The method and the results of the study provide a significant reference to improve the vehicle safety and reduce the occupant injury risk in pole side impact. |
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