Improvement Design Oriented To The Rollover Accidents Of The Large Passenger Vehicles

With the rapid development of our national economy and society, populationmobility has become more and more common these years, which requires higherreliability and safety level for traffic system. Among all the transportation means,large passenger vehicle still plays an important and irreplaceable role because of itslarge passenger capacity and low average cost. However, there are inevitabledisadvantages for this type of vehicle, one of which is that a large number ofcasualties would be caused in traffic accident. Therefore, large passenger vehicleaccident has always been among the special attention of researchers and governors. Inthis paper, concentration was focused on one typical type of traffic accidents, in whicha vehicle rolled over and collided with the roadside guardrail. Reconstruction of theaccident was obtained through computational simulation and improvements weremade on minimizing the damage based on finite element analysis. The main contentof this paper are as follows.Firstly, the finite element model of one12-meters-long large passenger vehiclewas built in Hypermesh. The whole process included geometric model building,necessary simplification, material and property setting for parts, finite elementmeshing, links between parts modelling, as well as1-D mass elements adjunction.Besides, quality check steps were followed for all elements to ensure the reliability incalculation.Another important part of traffic accident reconstruction was building finiteelement model of the roadside guardrail. The size of the guardrail was decidedaccording to national standard JTG D81-2006, Guidelines for Design of HighwaySafety Facilities. The model was also completed by imported into Hypermesh formeshing, material and property setting.With the finite element models of the vehicle and the guardrail, contact settingswere made to combine them for the accident. In addition, initial motion of the vehiclewas set based on regulation ECE R66. By explicit dynamic calculation in LS-DYNA, the whole process of the accident was reconstructed successfully. The severity of theaccident was measured according to the intrusion depth of outsiders into the residualspace, which was also defined for large passenger vehicle in ECE R66.Then the improvements were made to reduce the damage. On one hand, twopossible ways concerning the structure of the vehicle itself were proposed and verified.On the other hand, the structure of the guardrail was improved. A new type ofguardrail was introduced and a series of computational experiments were designedand executed to optimize the size parameters of the new guardrail. Experiment designmethod and data analysis are two important processes in optimization.In conclusion, in this paper the method for reconstructing one typical type oflarger passenger vehicle traffic accident was proposed and following improvementswere made to minimize the damage of accident. The improvement on vehicle’sstructure could play as a reminder to vehicle designers as well as a supplement forregulation ECE R66. Besides, the improvement and optimization result could bereferred by relative governors.