Design And Optimization Of Head And Chest Double-chamber Airbags For Vehicle Side Collision

With the increase in the number of car ownership,car safety accidents have become more and more,and occupant safety has become more and more important.In the event of a car side collision,because the side of the car is a weaker part of the car body,the structure space is smal,and the energy absorbing member is small.When the car body is subjected to a side impact,the side of the car body does not have enough deformation space to absorb the buffer impact force.The occupants were injured by collisions with doors,windows,and external objects,and even died in serious cases.As a kind of auxiliary safety tool,the side airbag of the vehicle mainly provides the passive restraint protection for the occupant,such as the head,chest,abdomen,and buttocks,and is mainly divided into a head airbag(curtain airbag),a chest airbag,and a chest hip airbag.At present,most vehicles are equipped with chest airbags,and some mid-to-high-end vehicles are equipped with curtain airbags.There is less analysis and research on the protection of dummy head and chest at the same time.Therefore,in order to improve the protective effect of the side airbag to the occupant,a head and chest double air chamber airbag structure is designed in this paper.The specific research contents are as follows:Firstly,the research status and development trend of automobile side impact at home and abroad are described.The research on airbags and side impact methods are summarized.The relevant European and American collision laws and regulations are compared and elaborated.In addition,the collision regulations in China and the C-NCAP side impact tests were introduced in detail.Based on a model to build the PSM of the side body.The model is based on the side crash data of the real vehicle and is established based on the vehicle data and the relevant data of the vehicle body and dummy in the crash test.The model mainly includes the vehicle body,seat,floor,side airbags and dummy,and the MADYMO software can directly call proven dummy.After the model is established,the model is verified according to the data of the actual vehicle test,mainly from two aspects of the dummy's movement pattern and the dummy's injury value.According to the comparison,the model error is within the specified range and the model is valid.The head-and-breast double-compartment airbag model was established,which mainly included the design of the airbag model size and the establishment of the basic model,the meshing and folding of the airbag model,and the establishment of a simulation model in the MADYMO software.The geometric design of the head and chest bag needs to meet the area that can protect the occupant's head and chest.from colliding with the side body after the air bag detonates.Airbag models are meshed in the simulation software to ensure that airbag mesh quality is critical for subsequent simulation work.Cross-interference should be avoided when the airbag is folded so as not to affect the airbag deployment.The head-and-breast doublecompartment airbags were introduced into the MADYMO software to set the relevant parameters when deploying the airbags,including: airbag simulation time step,airbag relaxation,airbag self contact,airbag material,airbag vent,and airbag burst time.Gas generator parameters,airbag thickness and so on.For the airbag,there are many parameters that affect its performance,such as the airbag volume,vent size,ignition time,airbag shape,airbag fabric material,mass flow rate,and so on.Several parameters that have a large impact on the airbag are selected: the size of the vent,the ignition time,and the mass flow rate for a one-way variance test.Through one-way analysis of variance method,the parameters of the airbag were screened to obtain the effect of the ignition time and mass flow rate on the protection of the airbag.Through the orthogonal test optimization of the selected parameters,the optimal parameter combination is selected.Comparing the results before and after optimization,it was found that the protection of the optimized thorax airbag to the head and thorax was improved,the comprehensive injury assessment value WIC decreased by 10.32%,and the overall performance of the restraint system was also greatly improved.The optimization of the head and thorax airbag achieved an effect..