Crash Simulation And Optimization Of The Highway W-beam Guardrail

In our country, about30%of accidents in the highway are caused by vehiclecrashes into guardrails. Recently, with great changes in vehicle patterns in thehighways, vehicle patterns gradually turn to miniaturization and heavy-duty.Therefore, it has important significance to research the mechanism of car collisions,identify the problems existing in the current highway guardrail, and try to improvecrashworthiness of guardrail in the new road situation.Firstly, this paper constructs the finite element model of the standard W-beamguardrail. After verifying reliability of the finite element model of the car, asimulation finite element model of car collisions with W-beam guardrail is established.Secondly, the resultant body acceleration and dynamic deformation of guardrail arestudied at different starting crash position of pick-up truck and guardrail. In theprocess, the body acceleration when pick-up truck collides with the current guardrailexceeds the20g limit prescribed by the standard of D81, causing greater damage tothe occupant. A dangerous situation straddling the guardrail occurs when truckcrashes into the current guardrail. Combined with the simulation result of pickuptrucks and trucks collision with the current guardrail, and with the guardrailevaluation standard of D81, F83, we conclude that the current guardrail can not meetthe protection requirements. Therefore, the orthogonal experiment is utilized tooptimize the design of the current guardrail. After that, appropriate factors and levelsof the orthogonal experiment are selected to optimize parameters of the currentguardrail, thus getting an optimization program, verifying that the optimized guardrailhas got great improvement in the indicators and that its performance meets therequirements of guardrail evaluation standard of D81, F83.Finally, with applying the H-shaped steel posts guardrail and H-shaped steelblock guardrail of the three-beam guardrail to W-beam guardrail,the finite elementmodels of three kinds of mixed guardrails are established, and pickup trucks are usedto study their crashworthiness. Simulation analysis shows that the resultant bodyacceleration of three mixed guardrail is greater than the20g limit prescribed by thestandard of D81. Therefore, it demonstrates that three mixed guardrail can not meetthe guardrail evaluation requirements of the standard of D81. According to conclusions of this study, the crashworthiness of optimizedguardrail in the orthogonal experiment is better than that of standard W-beamguardrail. It is proved that the three kinds of mixed guardrails fail to meet theprotection requirements through simulation results after applying the H-shaped steelposts and H-shaped steel block to the W-beam guardrail. The research results have acertain reference value for further improvement in our standard W-beam guardrail.