Study On Damage Indicators Of Passenger Cars In Rear-end Large Freight Car Accidents

Bus is an important means of transportation in China's road transportation industry.In recent years,with the increase of floating population and travel more increase in the number of bus for passenger transport is growing rapidly.The bus traffic accident rate is increasing,especially the serious traffic accidents,resulting in more serious casualties and property losses.In addition to some objective factors,the driver's operating error,fatigue driving,speeding and other behaviors are important factors.In-depth analysis of these accidents found:when the accident occurred,wearing a seatbelt crew damage in the accident is not wearing a seatbelt crew much smaller,different positions inside the car seat occupant injury also has the big difference.At present,the microcosmic kinematics parameters of bus collision occurs,occupant restraint and the occupant injury is less.It is not possible to clearly describe the changes of various kinematics parameters of the rear-end vehicle and the rear-end vehicle when rear-end accident occurs,as well as the movement state of passengers and the stress state of various body parts under different collision speeds.In order to study the occupant damage of different seats in rear-end collision and the change of kinematics parameters in rear-end collision.Using MADYMO software combined with the Hyper mesh,PC-Crash,Sketchup,Auto CAD software to establish the classic model of the bus Crash.Through the experiment to get a bus floor,windshield,seats,the coaming and other parts of the body stiffness characteristic curve,load into the model,representative in car body seat call 12 Hybrid III 50th percentile male dummy model,and establish the MB-FE(multi-rigid-body-finite element)seat belt.With the help of PC-Crash software represent the typical bus crash together,obtain the kinematics parameters of center of mass of the collision instant coach,at the same time,analyzing the relationship between the kinematic parameters of the vehicle and the occupant's kinematic state.Loading the kinematics parameter curve at the center of mass of the vehicle into the MADYMO simulation model to debug and verify the accuracy of the model.Simulation experiments were carried out under the conditions of seat-belt constraint or no seat-belt constraint.The results showed that:In the bus rear-end collision,safety belt can effectively reduce the degree of head,chest and leg injuries;the head HIC value,chest C3ms(g)value and thigh strength index FFC(kN)value of the occupant on the seat near the front of the vehicle were higher than those on the seat in the middle of the vehicle;the force between passengers and passengers can aggravate the head injury of passengers close to the windshield;the rear seat occupant injury degree occupant injury is more serious than the central vehicle seat;the relative impact velocity,the greater the occupant injury degree is higher.With the restraint of the safety belt,the relative collision speed is greater than 60km/h,and most passengers in the bus will suffer serious or even fatal injuries;without the restraint of safety belt,the relative collision speed is greater than 40km/h,and most passengers in the bus will be seriously injured or even die.The research results can provide theoretical support and reference for reappearance of rear-end accident,improvement of occupant protection measures and occupant injury research.