Study On The Effect Of Airbags On Drivers In Frontal Impact

With the convenient and fast micro pure electric vehicle as a transportation tool,the following is the micro pure electric vehicle crash safety problem.The overall space of micro pure electric vehicle is relatively small,and its front-end design,component structure and spatial layout are different from those of traditional vehicles.In case of vehicle collision,the airbag in the restraint system of the micro pure electric vehicle will become the last line of defense for occupant protection,and good airbag matching characteristics can effectively reduce driver and passenger casualties.In this paper,the finite element model of driver airbag of a micro pure electric vehicle was established by using Hyper Mesh and LS＿preport.The key technologies of airbag modeling were discussed in detail.At the same time,the airbag static deployment test was carried out to verify the accuracy of the finite element model of the airbag by comparing the size parameters such as the airbag deployment state and the projected area.Based on the theory of occupant restraint system,taking the airbag ignition time as the research object,according to the conservation of occupant impact energy and the principle of T_5in-30ms,the calculation formula of the optimal ignition time of airbag in front impact was deduced.A 23km/h low speed and full width crash tests were carried out on real vehicles,and the impact acceleration characteristics,vehicle deformation and dummy sitting posture of the vehicle simulation model were verified to verify the effectiveness of the vehicle simulation model.The 50km/h full-width frontal collision simulation analysis of the vehicle was completed.According to the C-NCAP regulations,the vehicle crash simulation results are analyzed in detail from two aspects of vehicle structure and occupant injury,and the vehicle B-pillar acceleration curve and restraint system parameters are extracted.Considering the calculation cost,in order to analyze the impact of airbag design parameters on the collision,the simulation model of micro pure electric vehicle was simplified.Taking the B-pillar acceleration of the vehicle as input condition,a simple constraint system collision model was obtained,including the constraint system,the front windshield,the firewall,the steering wheel and the floor.The reliability of the simple constraint system model was verified by comparing the dummy damage curves and damage indexes of the vehicle model and the simple constraint model.Dyna and Hypergraph were used to analyze 7 airbag design parameters,such as gas mass flow rate and ignition time,to occupant weighted injury criterion（WIC）,the main optimization factors of airbag were determined.Orthogonal tests with 3 factors and 7 levels were designed to investigate the influence levels of optimization factors on WIC,HIC,C3ms and chest compression,a priority scheme of parameter adjustment in preliminary matching and local matching of airbag was proposed.Furthermore,a high order polynomial proxy model of the key design parameters of the three airbags and WIC was constructed by using Minitab,and the parameters of the airbag were optimized by the proxy model.The results show that the optimized vehicle model has significantly improved the occupant protection effect,improves the diving problem of the dummy and meets the requirements of C-NCAP regulations.Meanwhile,it is verified that the ignition time of the airbag of the optimized model is consistent with the ignition time deduced by theory.