Analysis For Vibration Of Vehicle-Bridge Coupled System

Bridge structural dynamic response is one of an important issue in the bridge structure Kinetics. With the rapid development of modern road transport facilities, the increasing number of new bridges, traffic loads in the dynamic problem can not be ignored even more. Many scholars at home and abroad on the coupled dynamic response of the system have done a lot of research, but there are still many issues to be studied further.First of all, this paper studies the problem of the bridge system natural frequency We establish the vibration differential equation with the eigenvalue method and obtain three-dimensional map of the first three natural frequencies which changed with mass ratio,the stiffness ratio and location ratio of the coupling system and time history of midpoint deflection of beam when the mobile vehicles moving over the bridge Sports simulation experiment, Braking simulation method and Method of characteristics are used and the results of these three methods are compared accordingly. Simulation results show that the coupled system of the natural frequency is not constant, but have relation with the system mass ratio, stiffness ratio and the ratio of the position, if we substitute beam frequency for the natural frequency of the coupled system can sometimes produce large errors.Second, the isolator is installed into the Vehicle-Bridge coupling system, differential equations of this system are established, which can be settled with the method of numerical integration we study the dynamic response of initial speed, acceleration, isolator stiffness and damp that playing on the bridge system Comparative analysis also be done when not installing isolator and isolator mounting on the vehicle-bridge coupled system dynamic response. Numerical results show that Vehicle initial speed, acceleration dynamic have different effects on the coupled system. Isolator can help reduce the dynamic response of coupled systems, to improve the stiffness and strength of bridges.Finally, we do some research on more than one vehicle-bridge coupling system model and vibration analysis of the problem. Differential equations are established, which can be settled with the method of numerical integration. The numerical results show that the bridge system's dynamic response is not increasing when initial velocity increasing; Not the smaller the distance between vehicles, the greater the dynamic response of the coupled system only when the distance is zero or half of the bridge span, the maximum deflection is approximately twice the time for the one. When driving one car on the bridge, bridge damp has little effect on beam deflection, However, vehicles traveling over the bridge damp has a significant effect on dynamic response of the coupled system, especially for the largest deflection of the bridgeInnovation of this paper is putting forward and resolving the following vehicles-the bridge coupling system dynamics new problems in theory.1. The establishment of natural frequency theory about vehicle-bridge coupled system2. The establishment of the dynamic response theory that Isolator is built into the vehicle-bridge coupled system.3. The establishment of the dynamic response theory about multiple vehicles bridge coupled system.