A Study On Optimization Of Occupant Restraint System Based On Energy Analysis

Nowadays,the development of automobile technology is very rapid.At the same time,the traffic accident rate is increasing.The occupant restraint system(ORS),such as airbag and seat belt,is the main protective device in the vehicle and reduces the casualties significantly during the traffic accident.Therefore,the study of ORS is very important in the field of vehicle safety.At present,the ORS is developing more diversified and intelligent and it is a system with multi-parameter input and multi-response output.It's extremely important to find vital parameters to achieve rapid optimization,shorten the R & D cycle and reduce costs.In view of this problem,the new optimization method of ORS is innovatively put forward in this paper based on energy analysis.The main content is divided into the following parts:(1)The main research and methods in the field of automobile safety are introduced at first in this paper.And it also summarizes the development of ORS,optimization methods and energy of ORS at home and abroad.Then,the research method is combined with theoretical analysis to determine the main research contents and technology road map of this paper.(2)Based on the real vehicle crash test,a vehicle frontal crash simulation model is established in MADYMO7.5 software and the accuracy of it is validated.Five important parameters are determined from so many parameters of occupant restraint system by sensitivity analysis.Then orthogonal test method is used to obtain different parameter combinations of ORS and the corresponding whole injury criterion(WIC)of occupant.(3)On the basis of the energy theory and previous research method,the dummy is divided into four parts:head,thorax,pelvis and leg.Analyzes the process of vehicle frontal crash,the energy transfer and energy absorption of ORS value are cleared.(4)MATLAB is used to analyze the data of orthogonal experiments.The relationship between the WIC value and the energy distribution of ORS is qualitatively and quantitatively determined from the relation chart and the fitting formulas.The results indicate that the WIC is negatively correlated with the energy absorption peak(EPeak)of the safety shoulder belt,the safety lap belt and the car seat,and is positively correlated with the EPeak of the knee-bolster and the floor.(5)Analyzes the parameters of occupant restraint subsystems,such as safe belt,car seat.Then relationships between ORS parameters and its EPeak are constructed one by one by MATLAB.Combined with the relationship between the WIC value and the EPeak of each subsystem,the optimal parameter combination of occupant restraint system is determined.The optimal results are as follows :the safety belt fabric elongation is 13%,the ignition time of tensioner is16.7ms,safety belt's force is limited to 5400 N,the knee angle is 24.5o and knee stiffness is 93% of original value.In addition,when the floor friction coefficient is reduced a little and the seat cushion angle is adjusted to 9.5o with the horizontal direction,then safety belt and car seat reach the maximum energy absorption peak while knee-bolster and floor reach the minimum energy absorption peak.Under this circumstance,WIC value is 0.4023,7.35% lower than the original value and the performance of occupant restraint system is optimized.