Study On Guardrail Impacted By The Bus Performance Evaluation And Numerical Simulation

Over 110 thousands people caused by traffic accidents die annually. About one third offatal accidents are single-vehicle accidents involving the impact between vehicles androadside guardrails. The loss of the injury and treasure affects the safety of nationalproduce. As a result, the research of the impact between vehicles and guardrails hasmany realistic meaning. Summarized are the contents of two criteria about the safetyperformance evaluation of guardrails, EN1317 and NCRHP Report 350. Those areanalyzed and compared between two criteria including vehicle selections, guardrailprotecting levels, safety performance evaluation indexes and test methods. Whencriteria are founded in china, it should be considered that the test vehicle model mustrepresent the mainstream in the traffic road by statistical methods. Guardrailprotecting levels are ranked according with the different features of the real cases.New equipments and technologies should be attempted to apply into the evaluationsof the occupant injury indexes. But the evaluating index can be adopted as the foreigncriteria. For the evaluation of the guardrails using simulation technology, the finiteelement bus model is successfully built. Unlike a car crash test that typically lastsabout 0.1 seconds, the vehicle-guardrail crash test needs to be monitored for one secondor longer. This is a great challenge to the bus modeling in terms of balancing thestructural details and computational efficiency. To better capture the impact response,the bus suspension, the tire rotation, the steering, and the tire pressure are alsomodeled. The simulation correlates well with the test results in the local deformationof the bus, and more importantly, in the post-impact trajectory of the bus. Theprocessing of the validating methods is a sample using LS-DYNA to simulate theguardrail impacts. Moving Deformable Barrier (MDB) substituted the full vehicle canbe adopted in the test. The parameters of the MDB are set including with its mass, thecenter of gravity and dimensions as the criteria demanded. Deformable material isfitted in the crash zone of the MDB. There are some difficulties in measuring thematerial stiffness and selecting the material with the proper characters. Developmentof the MDB using in the safety performance evaluation will be the new method in theevaluation test.