The Equations Building Of Vehicle-Bridge Coupling Vibration Model And Analysis Of Dynamical Response

The structure of bridge will vibrate when the train passes through the bridge, while this vibration will also cause and affect the train vibration oppositely at the same time. This interaction between train and bridge is called vehicle-bridge coupling vibration. The coupling has the characters of changing as the time, self-excited and random, and the influenced factors are variety and complexity. Thus, we must take effective method to study the coupling system. For example, we must make some assumptions and abstracts, pay attention to the main factors and ignore the unimportant. So we can analyze and solve the problems exactly.In this paper, vehicle-bridge coupling system model is divided into three parts: the vehicle model, the bridge model and the wheel-track model. For the vehicle model,5 types of certain numbers of DOF equations are established respectively for vehicle with 4-axis. vehicle's DOF types include 42,35,31,27,23; For the bridge model, it's vibration equations are built by the finite element method through discrete method; For the wheel-track model, I use the elasticity contact theory, then work out the force of wheel-track, regarding the relation of wheel-track as connection of vehicle and bridge, then we can get vehicle-bridge coupling system's equations, through analyzing, sorting and ordering, we obtain static and variable matrix of coupling system. Finally, I write the Fortran language program, and make use of the numerical integration method to analyze the dynamical response of the bridge. In the end, I consider the track vertical irregularity as the coupling system's excitation and analyze the response of the middle bridge from time and frequent when the train pass through the bridge at the speed of 55m/s; then, I analyze response of bridge under different conditions that include different train velocity, bridge rigidity, span, different vehicle numbers and track irregularity value, and compare the results. At last, I draw many useful conclusions.Theory comes from practice and is applied to practice. I hope these conclusions can play an important part in reference and use value in bridge design, controlling, estimate of dynamic capability and reinforcement of bridge structure.