Research On Impact Of Deceleretion Energy Absorbing Facilities At The End Of Eer On Crash Of Vehicles

The emergency escape ramps force the out-of-control vehicle to decelerate by brake bed and the end deceleration energy-absorbing device.However,the vehicles entering the EER may still crash or break through the end due to reasons such as excessive speed and insufficient EER length.It can cause the vehicles rushing out of the end and falling into the cliff,which might did serious injury or death to the drivers then.Among them,energy absorbing tires and retaining walls lacks uniform standards,the stacking of tires is arbitrary,and the design of retaining walls is unreasonable.The research in this paper aims to provide a theoretical basis for energy absorbing tires and retaining walls.The main research contents of this paper are as follows.First,establish the finite element model of the out-of-control vehicle and the deceleration energy absorbing facilities respectively.The Ford F800 truck finite element model is used as the out-of-control vehicle model,and use Ls-Dyna to establish the 8R22.5 radial tire finite element model,then the effectiveness of the tire finite element model is verified through radial stiffness test and lateral stiffness;at the same time,Established finite element models of concrete and reinforced concrete retaining walls with a width of 4m and a height of 1.5m respectively.Second,carry out research on the impact of energy absorbing tires on crash with out-of-control vehicles.Carry out radial compression test and axial compression test on tires,and finally combine the vehicle model and energy absorbing tires to carry out horizontal stacking and vertical stacking crash tests respectively.From the aspects of the speed,acceleration and crash contact force of the vehicle,the two stacking arrangements were compared and studied,and finally the suitable stacking methods for energy absorbing tires under different conditions were obtained.Finally,carry out research on the impact of the retaining wall on the crash of out-of-control vehicles.According to the different vehicle and road factors,three variables including speed variable,load variable and gradient variable are set,and research impact of the restraint of the retaining wall on the vehicle when the vehicle crashes with two kinds of retaining walls between different variables.According to the influence of the retaining wall’s own factors,three factors including concrete strength,retaining wall thickness and retaining wall reinforcement ratio were selected,and design the orthogonal test scheme of L9(3~3),and analyze the test results by the extreme difference.Preliminarily determine the design scheme of the retaining wall at the end of the EER.