论文部分内容阅读
According to the accident statistics for buses,accidents involving frontal collision constitute an important percentage among all bus accidents.In this type of accidents,front body of the bus structure gets severely damaged and this puts the driver and crew at great risk of injury.And most of the frontal collision accidents result in death of the bus driver.Due to lack of national standards and industry regulations,safety performance in frontal collisions has been inconsistent.In frontal crashes,inadequate front cab design can easily result in high acceleration impulses and serious intrusion into the driver’s living space;inadequate seat and restraint design can easily result in ejection of passengers from the vehicle,death or injury over a large area.The purpose of the project is to identify safety design deficiencies in frontal collisions of buses and to propose protective measures for bus drivers and passengers.Key elements of the research for this topic include.Bus frontal collision testing and analysis.Based on the test method of the draft bus frontal collision standard,a bus frontal collision at 30 km/h was conducted to examine the deformation characteristics of the bus front structure,acceleration momentum characteristics,driver life space intrusion characteristics,and passenger injury characteristics at various locations to identify safety design problems of the bus front structure and causes of passenger injuries.The results show that the structural integrity of the front of the bus is insufficient,leading to more serious intrusion into the driver’s space;the acceleration peak is high,which does not help to protect passenger safety,especially causing more serious injuries to the driver’s neck.Simulation modeling of buses and passengers.A finite element model of the bus and a model associated with the passenger and bogie were created using the finite element-multibody method to evaluate the effects of design factors on the cab’s living space;the simulation model was validated by combining a crash test of the bus and a test on a driving track.The results show that the finite element model and the passenger-carriage coupling model have high accuracy and can be used for further design optimization and passenger protection research.Optimization of the front of the bus.The design of the front of the bus is improved to improve the consistency of load transfer in frontal collisions.Using a sensitivity method,the components with the greatest impact on driver survivability were selected;with no more than 12 g peak acceleration constraint and minimum survival impairment as the optimization goal,the front structure design parameters were optimized using the Latin squares method,response surface method and annealing algorithms to obtain the optimal front bus cab design to ensure that driver survivability is not impaired.Protective measures regarding the use of seat belts.Due to the high rate of head and neck injuries to passengers in crash tests,differences in injury characteristics between passengers wearing no seat belts,twopoint seat belts,and three-point seat belts are compared,and recommendations for the use of seat belts for different driver positions are discussed.The results show that the use of 3-point seat belts can reduce the risk of occupant injury in all directions,especially in terms of neck protection,and can significantly reduce neck bending moments.