| In recent years,the state has reintegrated educational resources and implemented the policy of relocating and merging schools.According to incomplete statistics,the number of primary and secondary school students in China has reached 180 million,and the potential demand for school buses has reached 1.2 million.However,under the current growing demand for school buses,a large number of school buses that do not comply with relevant laws and regulations flood into the market,which has a huge potential risk to the safety of children passengers.To standardize the school bus market and ensure the safety of children passengers,the government has promulgated a series of regulations and standards about the school bus.Because of the deficiency of the existing bus occupant restraint system in child occupant protection,this paper introduced a reusable active airbag combined with the characteristics of the airbag.Since the school bus was designed for primary and middle school students,whose age span is 6 to 12 years old,this paper studied the protective effect of active airbags on children aged 6,8 and 12 years old.The main research contents of this paper are as follows:1)Referred to the literature of the school bus occupant restraint system at home and abroad,and summarized the current situation of the use of school buses,the research status of bus occupant restraint system and active airbags.2)Established a school bus occupant restraint system model.According to the actual parameters of a school bus(a front seat,a rear seat,a two-point seat belt,the floor,and Hybrid III dummies),the school bus occupant restraint system for the Hybrid III 6-year-old child dummy and the Hybrid III 5th percentile female dummy was established and verified.The results of the sled test for the school bus occupant restraint system were compared with the simulation.It has been found that the school bus occupant restraint system model can reproduce the results of the sled test and meet the accuracy requirements of the simulation analysis.The structural characteristics of the active airbag were studied and the MADYMO model of the active airbag was established to form a kind of new school bus occupant restraint system models.3)Studied the protective effect of active airbag control parameters on children of different ages.The control parameters of the active airbag were the upper drawstring length,the middle drawstring length,the lower drawstring length,the mass flow rate of gas,airbag installation position,valve opening pressure,valve opening degree,and seat spacing.The influence of the eight active airbag control parameters on the injury index values of children aged 6,8,and 12 were studied.Based on the WIC,the seat spacing had the most important impact on the occupants of the 6-year-old,8-year-old and 12-year-old children.The valve opening pressure had a great influence on the occupants of children aged 6,8 and 12.4)Researched and optimized key control parameters of active airbags.Based on the sensitivity analysis method,the key control parameters of the active airbag were selected,and the nonlinear regression equation of the WIC and the key control parameters of the active airbag were constructed by using the Latin Hypercube test design method and the principle of the second-order polynomial response surface model.After verifying the equation by samples,the optimal combination of the key control parameters of the active airbag was solved.It was concluded that the active airbag optimized occupant protection effect for children compared with before optimization was improved.6-year-old children’s WIC was reduced by 29.65%,8-year-old children’s WIC was reduced by 27.89%,12-year-old children’s WIC was reduced by 47.19%.5)Studied the control strategy of the valve based on the weight of the child occupant and the speed of the school bus.The second-order polynomial response surface model of the WIC and valve control parameters under different children’s qualities and the speed of school bus was established and the optimal combination was solved.According to the above research,the equation between the children’s quality,the speed of school bus and the control parameters of the valve was constructed.By studying the control strategy of the valve based on the children’s quality and based on the speed of the school bus separately,the relationship between the children’s quality,the speed of the school bus and the control parameters of the valve was comprehensively analyzed to formulate the control strategy of valve: the active airbag control system monitors the weight of the child occupant and the real-time driving speed of the school bus,and matches the control parameters of the valve in real time based on the relationship between the control parameters of the valve and the children’s quality and the driving speed of the school bus,so as to further improve the collision safety of the child occupant. |
PDF Full Text Request