Research And Optimization Of Conjoined Active Airbag For School Bus

With the development of society,children's pre-school education and compulsory education have been paid more and more attention.In 2018,there were 10.937 million primary school students and 46.564 million children in kindergartens.The potential demand for school buses is huge.Due to the frequent occurrence of school bus accidents,the development of school bus safety has also been put on the agenda.At present,most of the restraint systems for school bus passengers only have two-point seat belts.Through previous studies,active airbags have been designed for school buses.Because children are active and prone to ride without seat belts offset,this paper proposes a school bus connected active airbags to protect offset children.Firstly,after reading literature,news and regulations,this paper summarizes and summarizes the development status of school bus safety at home and abroad,compares the differences between domestic and foreign school bus equipment,summarizes the evaluation index of school bus occupant injury and domestic and foreign laws and regulations,and introduces the development trend of safety airbags at present.This paper introduces the school bus frontal impact trolley test based on the simulation institute,establishes front and rear seats,floor and two-point seat belt through MADYMO,completes the construction of occupant restraint system for Hybrid III 6-year-old dummy school bus frontal impact,and compares the simulation model with the trolley test,which verifies the validity of the model.This paper introduces the design principle of the active airbag for school,establishes the model of the conjoined active airbag for school buses,and simulates the working conditions of double,single occupancy and mid-offset respectively,and compares it with the single airbag.The validity of the conjoined airbags for the protection of offset children was verified,and the insufficiency of the conjoined airbags for the protection of double and single occupancy was found.Single factor analysis was conducted to determine the impacts of seven parameters on the injury of 6-year-old children's passengers in double and single occupancy conditions.Taking the change of WICs as a reference,the same parameters that have a greater impact on occupant damage under the two conditions are the diameter of exhaust holes,gas mass flow rate,installation position of airbag and the opening pressure of exhaust holes.However,the influence of the diameter of exhaust holes and the opening pressure of exhaust holes on the two conditions is opposite.Through sensitivity analysis of WICs change rate,the five most significant parameters under two working conditions,double-ride and single-ride,were selected respectively.Orthogonal test optimization was carried out and the results of range analysis were used to obtain the optimal combination of airbag parameters under their respective working conditions.Considering the practical significance,the multi-objective optimization of two working conditions is also carried out.Two quadratic polynomial response surface proxy models were constructed by selecting the same sensitive parameters and using Latin hypercube sampling test to collect data.The Pareto frontier curve of spatial distribution of the optimal solution set is obtained by solving the two objective functions using NSGA-II multi-objective genetic algorithm in MATLAB.The optimal solution is selected according to the actual meaning of the objective.The results show that the protective effect of conjoined airbags on offset children is improved obviously when the protective effect of double and single occupancy is up to the standard.The WICs is 36.1% lower than that of single airbags,only 0.4057,which greatly enhances the effective protection of offset children in the school active airbag restraint system.