Research On Crashworthy Structures And Collision Safety For High-Speed Trains

With the advent of high speed railway, traveling periods among cities and districts are becoming shorter and shorter. It is essential to develop high speed railway systems in large countries like ours. However, it is possible to bring bad damage once a collision accident happened between high speed trains. The like disasters taking place now and then indicate that it is necessary to research the passive safety protection technology on trains. Based on the present research status at home and abroad, crashworthiness structures of high speed vehicles and occupants’ safety are studied by nonlinear FEA simulation method.First of all, theories of materials, element types, contact methods and arithmetic which are involved in train collision simulations is explained and several critical problems in crash worthiness train design and simulation. Specially, the possible effects from the strain rate on simulations are discussed and mechanical characteristics of couplers and buffers are simulated by discrete beam element in LS-DYNA which contains loading, unloading and dropping off under extreme loads.Secondly, considering the high speed and huge kinetic energy of high speed trains, energy absorbing structures are proposed for both ends of a vehicle. For the cab end a two-stage energy absorbing device is studied, the outer housing of both of the stages is made from thin metal sheets, and the first stage is filled with aluminum foam while circular pipes for the second. By weaken side beams under the side doors, the no seat door regions are designed to have the energy absorbing ability. The aimed function of the energy absorbing energy structures is to protect the integrity of the cabs and occupants’ areas which is validated in this paper.And then the energy absorbing structures mentioned above are applied to all eight vehicles of a high speed train set and three classic scenarios are evaluated and the dynamic responses like velocities and accelerations, impact forces and energy managements are paid more attention. In order to assure the simulating accuracy, all vehicles are discretized using their real models with only little simplifications.Finally, the occupants’ safety during the second collision under classic scenarios are evaluated meaning of standards or methods developed in motor-dom. Reasonable arrangement for occupants’ space and seats can effectively keep occupants safe. How the seat pith, the stiff of seat backs, and the seat belt can affect occupant’s safety is also studied and relevant suggestions are proposed.