Coupled Vibration Analysis Of Vehicle-Bridge System Of New Railway Emergency Steel Beam

With the development of computer technology, FEM theories and multi-body system dynamics, it has become possible to study the vehicle-bridge coupling vibration problem. The new type railway emergency steel beam is used as a kind of traffic emergency repair equipment. Because its longitudinal and lateral stiffness is much lower than that of the concrete box-girders, for the sake of safety, the vehicle-bridge coupled vibration analysis become necessary. In this paper, the calculation models of railway freight cars subsystems and truss bridge subsystems are set up respectively using the above mentioned software. Moreover, the corresponding vibration analysis is carried out through data exchange of discrete information of the wheel-rail interface between two subsystems to realize the simulation vibration analysis of the coupled system.Firstly, constructing the finite element model of the bridge by ANSYS, the substructure modal analysis is carried out. The natural frequencies and modes of the steel beam are obtained. At the same time, the basic theory of multi-body dynamics and the equations of railway vehicle motion are introduced, and the composition and characteristics of the vehicle model in SIMPACK are analyzed with the specific characteristics of railway vehicles. By means of the force elements and motion constraint hinges, which reflect the complex characteristic of the object, the rigid bodies in the model are connected and restricted by each other. On the basis of the full consideration of the nonlinear factors in the model, a three-dimensional model of the vehicle is built. By checking the nominal force to get maximum residual acceleration, the validity of the vehicle subsystem model is verified.Secondly, in this paper, the methods of wheel/rail force and wheel/rail tangential creep force are mainly introduced based on the relationship between the wheel and rail contact, besides, non-linear critical speed is calculated applying a single integral method.Finally, within the range of design speed, the dynamic characteristics of the new type railway emergency steel beam and vehicles have been analyzed. The dynamic deflection and acceleration of the steel beam have been analyzed with relative codes, also the safety indexes(derailment coefficient, rate of wheel load lightening and transverse force) and stability indexes(vertical and lateral acceleration of the body and Sperling comfort indexes) of the truck vehicle.