| Heavy haul railway transportation is widely valued by railways all over the world because of its large transportation capacity,high efficiency and low transportation cost.Prestressed concrete simply supported T-beam bridges are widely used in heavy haul railway bridges.In addition,with the continuous improvement of the annual traffic volume of the line,the axle load of freight train and the speed of freight train,the dynamic effect of the freight train on the bridges is increasing,and the problem of fatigue damage caused by bridges needs to be further studied In this thesis,the dynamic analysis model of the train-track-bridge coupling system is established through multi-body dynamics software SIMPACK and finite element software ANSYS,the vibration response law of the coupling system is explored under the heavy haul freight train,the fatigue damage analysis and residual life assessment of simply supported T-beam bridge are carried out.The main research contents and results are as follows:(1)The train-track-bridge coupling system model is established.The freight train is regarded as the multi rigid body system,which is mainly composed of rigid bodies such as train body,bolster,side frame,wheel,suspension system,center plate and side bearing device connecting the above rigid bodies.The bridge and track are regarded as the flexible structure,which are simulated by solid element solid185 and beam element beam189 respectively.Through the wheel track contact relationship and bridge track connection relationship,the coupling among freight train,track and bridge is realized,and the correctness of the coupling system model is preliminarily verified.(2)The spatial coupling vibration analysis of heavy haul freight train-track-simply supported T-beam bridges are carried out.Take the C80 heavy haul freight train as an example,the dynamic analysis model of the coupling system is established,the basic characteristics of the vibration response of the coupling system are explored,and the influence laws of factors such as the number of freight trains,the speed of the freight train,the load of the freight train,and the span of bridge on the vibration response of the coupling system are analyzed.(3)The variation law of fatigue performance of prestressed concrete T-beam bridges under different driving conditions was explored.The results show that when the number of freight train marshalling reaches 4and beyond,the fatigue damage of the bridge basically no longer increases,so more long-marshalling freight train should be used on the actual line;Compared with T-Beam with 16 m,20m and 24 m spans,T-Beam with 32 m spans are more likely to suffer fatigue failure;The bridge fatigue damage degree is positively correlated with the freight train speed and freight train load.(4)The fatigue life assessment of 32 m prestressed concrete simply supported T-beam bridge on Shuohuang Railway is carried out.The fatigue load spectrum of Shuohuang Railway is calculated and predicted,The residual service life of the bridge is calculated by using the fatigue life assessment method based on S-N curve and Miner linear cumulative damage criterion.The results show that under the independent action of the external load of the freight train,the bridge will not suffer fatigue failure within the design service life. |
