Simulation And Parameter Optimization Of Occupant Restraint System Under Vehicle Frontal Collision Condition Based On LS-DYNA

Nowadays,the incidence of road traffic accidents has increased year by year,and the problems of vehicle safety have become increasingly prominent.In the car collision accident,the occupant restraint system can effectively reduce the occupant injury and improve the vehicle safety.The combination of finite element simulation analysis and real vehicle crash test has important guiding significance for shortening the vehicle development cycle and reducing development cost.In this paper,the vehicle collision occupant restraint system is taken as the research object.By constructing the simulation model,the structural parameters of the main components of the occupant restraint system are optimized and analyzed,which improves the protection effect of the occupant restraint system.The main research contents are as follows:Firstly,the finite element pre-processing software ANSA was used to construct the vehicle collision occupant restraint system simulation model.The model includes the car body structure model,the seat belt model,the seat model,the airbag model,and the connection settings,contact settings,control parameter settings and collision waveform loading settings of the model,and import LS-DYNA software to calculate the model.Secondly,according to the national automobile collision safety regulations and evaluation system,the occupant injury evaluation criteria are determined.For the simulation model,the dummy’s motion response is analyzed,and the injury values of the occupant’s head,neck,chest,and femur are evaluated.The data of the vehicle crash test is used to compare and analyze the data to verify the validity of the simulation model.Thirdly,the orthogonal test is used to match the structural performance parameters of the occupant restraint system.Sensitivity analysis method is used to investigate the response of each parameter change to the damage of various parts of the restraint system,and determine the reasonable range of parameters.Then,orthogonal test design is carried out for the variables with large influence,and the method of range analysis is used to evaluate the parameters with significant influence by using the weighted damage criterion as the evaluation index.Thus four design variables were selected:airbag ignition time,airbag vent diameter,seatbelt force rating and seat belt friction coefficient for subsequent optimization.Finally,the occupant restraint system is optimized by using the approximate model instead of the finite element simulation model.Through the experimental design,the approximate model of response surface method and Kriging function method is established respectively.The weighted damage index is used as the criterion.The two approximate models are optimized by numerical optimization method and NSGA-II genetic optimization algorithm,and comparative analysis is carried out to select the most.The excellent results are brought into the simulation model for verification.By comparing the output results of the simulation model before and after optimization,the weighted damage index is reduced and the C-NCAP score is improved,which indicates that the parameter optimization design of this paper achieves the goal,reduces the damage index of each part of the occupant,and improves the protection efficiency of the occupant restraint system.