Study On Acting Factors Of Coupling Vibration Of Vehicle-Bridge And Analysis Of Random Vibration

With the constant improvement of running speed, increasing of traffic density and the gradual augment of the load, dynamic force interaction between vehicle and structure is more and more crucial, especially for bridge structure. The dynamic response of the vehicle and bridge is more impetuous when the bridge is impacted by the running vehicle on it because of bridge's characteristic, for example, the wider span and the lower rigidity. On the other hand, the vibration of bridge caused by vehicle also affects the vibration of vehicle at the same time, the safety and steadiness of movement is weakened, so the relation forms the vehicle-bridge coupling vibration. This issue of vehicle-bridge coupling vibration is extremely complicated because the interactional course is random, variational as the time and nonlinear in structure and material.Firstly, in this article a new vehicle-bridge model is constructed, this model is a dimensional and all-sided one including vehicle, bridge and the wheel-rail interaction, it accords with the actual system more since the elastic touchment of wheel-track is added in. on the basis of this model the vehicle's dynamic formula and bridge's finite elemental dynamic formula are set up, the vehicle's model has thirty-one DOFs and all wheels'DOFs have no relations with bridge's ones, which is different with the old model. Then, we set up the dynamic formula of the whole system adding in wheel-track force. Provided that track irregularity is an astationary ergodic Gaussian random process, a series of sample is simulated instead of the actual process and we must assure that it is long enough in time domain. Thus, we input the sample to the vehicle-bridge system and use the compiler computational procedure to obtain the result of dynamic response through the numerical integration method. The mass matrix, damp matrix and rigidity matrix in the dynamic formula of the vehicle-bridge system change frequently as the time, in other words, they are all temporal function, in addition, the form of matrixes and the position of nonzero number also change accordingly, which result in that at every new time, the matrixes is computed and parsed renewedly. This course shows the essence of vehicle-bridge coupling vibration and the characters of this issue typically, so it is very intricate obviously. In the end, vehicle-bridge dynamic response is analyzed in the theory of random vibration because that the inducement which caused vibration is random.Theory comes from practice and is applied to practice. Many valuable conclusions can be drawed through the analyse of dynamic response under the different condition in time and frequency domain, they can be used in the design of bridge structure and to simulate the actual locomotory course on suppositional bridge and estimate the security. The advance and limit of speed when vehicle runs on bridge can be directed by these conclusions. In addition, they can be used to direct the control of vibration, estimate of dynamic capability and reinforce of bridge structure. We can ensure that vehicle runs on the bridge safely by way of combination of the academic analyse and experiment, at the same time, in the aspect of design of vehicle and bridge this conclusion can be used as reference and show the significance on the safety, comfort and stabilization theoretically.