| It is of great theoretical and practical significance to study the highway vehicle-bridge coupling vibration.On the basis of dynamical theory, the vibration differential equations of vehicle model with five degrees of freedom are derived. Road roughness, which is main motivation to vehicle-bridge system, of grade A,B,C and D divided by national standard is simulated by the use of Triangular Series Method. In this thesis, bridge and vehicle are taken as two separate systems, which are connected by the conditions of geometric compatibility and force equilibrium. The forces acting on the vehicle are formed according to roughness and initial condition. Newmark-B method is used to solve the differential equations and to obtain the time-response sequence of vehicle system, and then the forces acting on the bridge are formed according to the results calculated. The large-scale software Ansys for structural analysis is used to calculate the dynamic responses of bridge, and then the forces acting on the vehicle are formed again according to the dynamic responses of bridge and roughness. The command stream, which is compiled by APDL language for secondary development in Ansys, is used to calculate the dynamic responses of vehicle-bridge system. The complicated models of bridge and vehicle can be taken into account by this method, so the method is highly versatile and can make up the deficiencies in previous methods to study the problems of highway vehicle-bridge coupling vibration.On the basis of the method, the influences of different kinds of factors such as road roughness, vehicle weight, velocity, suspension stiffness and damping, tire stiffness and damping, bridge stiffness and damping on the dynamic responses of bridge and vehicle, vehicle impact factor and the passenger's comfort are analyzed. In the end, some significant conclusions are obtained:1. With the decrement of road grade, the dynamic responses of the bridge and vehicle and the vehicle impact factor increase doubly, whereas the passenger's comfort decreases significantly.2. With the increment of vehicle velocity, vehicle impact factor and the dynamic responses in midpoint of the bridge span increase. The effect of the vehicle velocity on vehicle dynamic responses is related to the grade of road irregularity.3. While the increment of vehicle weight, the dynamic responses in the midpoint of the bridge span decrease first and then increase; the vertica dynamic responses of the vehicle decrease.4. With the increment of the bridge suspension stiffness and damping, the dynamic responses in the midpoint of the bridge span, vehicle impact factor increase.5. With tire stiffness increasing, the maximum dynamic displacement, acceleration and bending moment of midspan tend to increase first and then decrease, while the maximum dynamic shear tend to increase; except dynamic shear of midspan, dynamic responses will increase with the augmentation of tire damping. Tire stiffness and damping have little effect on vehicle impact factors. With the increment of tire stiffness, the dynamic responses of vehicle decrease first, and then increase. With the increment of tire damping, the dynamic responses of vehicle decrease and passenger's comfort improves.6. With the increment of the bridge stiffness, the dynamic displacement and the acceleration in the midpoint of bridge span decrease, the shear force and the bending moment in the midpoint of bridge span increase, and vehicle impact factor increases. With the increment of the bridge damping ratio, the dynamic responses of bridge decrease. The magnitude of damping has little influence on vehicle impact factor. The effect of bridge stiffness and damping on vehicle dynamic responses is small, the overall tendency is that the vehicle dynamic responses increase and passenger's comfort decreases with the increment of the bridge stiffness and damping.The method has a wide range of application and is able to analyze the coupled vibration of vehicle-bridge of complex vehicle and bridge expediently.
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