Coupled Vibration Analysis Of 87-type Railway Emergency Repair Steel Beam Under Heavy Haul Train

The long-span military railway beams especially the 87-type railway emergency repairing steel beams,play an important role in the logistical support during wartime and in the emergency repair of railway accidents.As the axle load of the train increases,it is of great significance of theory and reality to further analyze the stability of the 87-type beam structure and the safety of the train operation by working on the dynamic behavior of the 87-beam under the action of the C70 heavy-haul train.With the development of computer technology,finite element analysis theory and multibody dynamics,the use of software to simulate has become the primary means of studying the coupling of vehicle-bridge.This paper elaborates the development of bridge-vehicle coupling analyses by means of studying the research results at home and abroad.BEAM188 in ANSYS was used to establish five kinds of 87-type beam finite element models.At the same time,some calculation were finished in ANSYS,in which includes the natural vibration frequency and vibration mode of beam and evaluated the natural vibration characteristics.Based on the theory of multibody dynamics,a 42 DOF vehicle model is established using BODY,JOINT and FORCE,etc.in UM.The vehicle bridge model is established based on the wheel-rail contact,the track irregularity spectrum was used as the system excitation to exchange data at discrete information points on the wheel-rail contact surface.The reliability of the vehicle model is verified by calculating the critical speed of vehicle nonlinearity.UM is used to analyze the dynamic response indexes of C70 heavy-haul trains running through various spans of 87-girders.At the same time,the influence laws are analyzed,in which includes bridge span,running speed,irregular conditions and marshalling forms on the dynamic response of the bridge and vehicle are analyzed.The conclusions obtained are as follow: the lateral stiffness of the spans of 87-type is weak,and the vertical stiffness fits the specification requirements;while reached the resonance speed,the dynamic response of the axle is increased differently;the vehicle dynamic response shows great changes with different track irregularity conditions;compared with heavy-haul marshalling,heavy-empty marshalling and empty marshalling have more dynamic responses,which means that it is important to limit the operating speed;Reasonable recommendations are provided for the safe operation speeds of heavy-haul train in each span of 87-beams combined with the analysis data,for reference only.