Study On The Damage Of Thin-wall Long Rod Structure To Vehicle Lamps And Occupants’ Lower Limbs Based On Collision Isolation Guardrail

It is found that after the collision between the vehicle and the isolated guardrail,the crossbeam is more likely to form an open thin-wall long pipe structure damage to the car body,and even penetrates into the vehicle to cause damage to the occupants.It has been studied that the beam on the guardrail penetrate the windshield in front of the vehicle and causes penetration damage to the occupants,but the damage of the long pipe structure formed by the beam under the guardrail to the car body and crew may be ignored easily.The actual accident shows that after the car collides with the central isolation guardrail,the beam under the guardrail may form an open long tube to penetrate the car body from the headlamp,which will penetrate the vehicle under certain conditions and cause damage to the lower limbs of the occupants.Therefore,it’s necessary to study the impact of the long tube structure of the deformed guardrail on the headlamp and the lower limb of the human body.In order to solve the problems above,firstly,the collision model between the whole vehicle and the guardrail is established by finite element simulation experiment,and the simulation results showed that the lower crossbeam of the guardrail would collide with the headlamp and damage the vehicle body after collision.Based on this situation,a simplified collision model of headlamp and guardrail long pipe structure was established to analyze the penetration process of long tube structure to front lamp.Furthermore,the influencing factors of long tube penetration headlamp including collision velocity,angle and long tube port condition were combined,and 144 groups of simulation experiments were used to analyze the conditions of long tube penetration lamp.The experimental results showed whether the long tube can penetrate the profiled port pair or not.When the collision velocity was less than 30km/h or the collision angle was less than 30°,the long tube may not penetrate the headlamp when the collision velocity was in any combination factor of 40～70km/h and the collision angle was 60 ～90 °.In addition,the collision simulation model of multi-tube structure and headlamp was established,and the impact of multi tube structure on headlamp at different impact speeds is analyzed.The results showed that the front lamp is damaged seriously afterthe collision between the multi-tube structure and the headlamp.When the collision velocity was greater than 30km/h,the multi-tube structure could penetrate the headlamp,and the open thin-wall long tube structure would be formed after penetrating the headlamp.Based on the condition of the long tube penetrating the headlamp,the damage of the lower extremity of the occupant caused by the long tube structure piercing the headlamp into the vehicle was further studied.The collision model of tibia,fibula and long tube was established,and the damage of tibia and fibula under the different collision velocity,collision angle and long tube opening degree was analyzed according to the simulation results.The results showed that the long tube continued piercing the body of the car after penetrating the headlight and collided with the occupant’s calf,which could lead to open fractures of the tibia and fibulae of the lower leg.And the faster the impact speed was,the smaller the angle was,the shorter the fracture time occurred and the more serious the injury was.Abnormal ports can cause more serious damage.Finally,a new type of guardrail structure design scheme was proposed and its performance was evaluated by the mean of simulation analysis.The results showed that the performance evaluation of the new type of guardrail could not only meet the design requirements but also not form the open-wall long-tube structure which can threaten the safety of the passenger,and the impact of the collision between the car and the new guardrail on the living space of the passenger was small,and the safety was improved.In summary,this paper studied the collision between the open thin-wall long rod structure and the front lamp and the damage to the lower limbs of the occupants,and put forward the design scheme of a new guardrail to avoid the formation of the open thin-wall long rod structure,which provided a reference for the design of urban road guardrail and the formulation of related industry standards to a certain extent,and provides a new idea for vehicle collision safety and occupant protection.