Consider deck irregularity affecting road vehicles - bridge coupled vibration analysis
|School||Central South University|
|Course||Bridge and Tunnel Engineering|
|Keywords||coupling vibration of vehicle-bridge dynamic response vehicle model finite element method road surface roughness program|
So much extensive attention has been paid to the dynamic response research of bridges under moving vehicle load. The research results of Railway Bridge have been embodied in the design codes, while it is basically a blank in the design codes of Highway Bridge. With the rapid development of modern highway communication, new bridges being built, new types of bridge structure being emerged continuously, and the bridge span being increased, how to improve the evaluation methods of current bridge codes from static index to vehicle-bridge dynamic responses index becomes a problem which needs to be solved urgently. By reviewing relative literature, the theory and application research about road vehicle models, bridge models and their vibration equation establishment, coupling vibration of vehicle-bridge and the impact of bridge deck roughness are carried out. The main research work and results are as follows:1. Based on the assumption of rigid-body dynamics and dynamics of vehicle, the paper establishes respectively the vibration differential equation of seven degrees of freedom whole vehicle model, four degrees of freedom two-axis plane vehicle model and two degrees of freedom single-axis plane vehicle model, and transforms them into matrix form. What’s more, the applicable conditions of the three vehicle models are analyzed.2. In this thesis, vehicle-bridge coupling vibration system is taken as two separate systems:bridge and vehicle, which are connected by the condition of geometric compatibility condition and vertical force equilibrium condition at the contact point of wheel with bridge deck. Separation iteration method is used to solve the equation. Based on FORTRAN platform and combined with the secondary development function of ANSYS, the author compiles the numerical simulation program APVBCV(Analysis Program for Vehicle and Bridge Coupling Vibration) which can be applied to solve the coupled vibration of vehicle-bridge system. Through analyzing the model of seven degrees of freedom vehicle-bridge vibration and the model of uniform force across bridge, the program and the models are proved to be reliable from the related results.3. Road surface roughness is introduced to simulate bridge deck roughness. It is assumed to obey Gauss probability distribution, with zero mean, ergodic stationary random process. The author compiles the simulation module SUB_BDR based on FORTRAN platform. In this paper, road roughness of grade A-D divided by national standard GB/T7031-86 are simulated by the use of Harmonic Addition Method.4. On the project background of a three-span continuous beam which is the main bridge of Beijing-Hangzhou Grand Canal NO.2 Bridge, parameters analysis and calculation for vehicle-bridge coupling vibration are done by using the program APVBCV. The impact of parameters to the dynamic response of bridges is analyzed, such as number of lane and vehicle, grade of bridge deck roughness, speed, vehicle load, car spacing and the natural vibration characteristics of vehicle. In the end, some useful conclusions are obtained which can provide references for the further study in coupling vibration of vehicle-bridge.