Reliability Optimization Design Of Occupant Restraint System Based On Front Pole Impact

With the continuous improvement of people's living standards,the requirements for vehicle safety performance also increase.Therefore,it is necessary to do more in-depth research of vehicle safety.At present,the scholars at home and abroad also have conducted in-depth research on the crashworthiness of vehicle body,injury characteristics of occupants and optimization of restraint system under the conditions of front 100%overlap impact and frontal 40%offset impact.Though the accident rate of front pole impact is small,the injury to the occupant is serious.However,there are still few researches on the optimization of occupant restraint system at front pole impact case,and there is still short of occupant injury evaluation criteria of front pole impact test.Therefore,it is necessary to take an in-depth study of the characteristics of occupant injury and the optimization methods of restraint system under front pole impact.In this paper,the characteristics of vehicle body deformation and occupant injury under frontal pole impact are studied,and the optimization design method of occupant restraint system is discussed.The specific work and contents are as follows:1?The finite element models and the driver side constraint system model of front100%overlap impact and front 40%overlap offset impact of a passenger car are established,and the finite element model and the occupant restraint system model are verified through the test results.2?Based on the verified vehicle impact finite element model,the finite element model of frontal pole impact is established.According to the simulation results of the frontal pole impact with finite element model,the deformation of the vehicle body and the causes of the acceleration peak appeared earlier and larger under the collision of the frontal pole impact.The injury characteristics of occupants under frontal pole impact are analyzed according to the injury evaluation method of occupants under the condition of frontal 40%offset collision.3?Based on the weighted injury criterion,this paper establishes an occupant comprehensive injury value,which is suitable for the purpose of this study.And the occupant comprehensive injury value is taken as the optimization objective.The six design parameters of safety belt and airbag are taken as design variables.Then the response surface model,Kriging and radial basis function are established,and the error analysis of the three surrogate models is carried out.According to the prediction accuracy,the most reasonable surrogate model for each response is selected,and then the deterministic and reliability optimization of the constrained system is carried out.Finally,the reliability optimization results is verified by the multi-body dynamics simulation methodThe results show that the head,chest and legs of the occupants are seriously injured under the impact of the front pole impact.The injury of head and chest is related to the larger acceleration peak,the main reason for serious leg injury is the large amount of vehicle body intrusion.Compared with the initial design,the deterministic results lead to a greater reduction in occupant comprehensive injury.However,the optimization result of the head injury index HIC₃₆6 does not satisfy the reliability requirement.The reliability optimization increases the reliability of the head injury index HIC₃₆6 from91.4%to 99.8%.The reliability optimization results not only reduce the injury of the occupants but also satisfy the reliability requirements.