Due to extensitve application of bridge structure on high speed railway line, it is necessary to consider comprehensively the common effect of the train, the track and the bridge. By forming an integrated large system...Due to extensitve application of bridge structure on high speed railway line, it is necessary to consider comprehensively the common effect of the train, the track and the bridge. By forming an integrated large system including the car and locomotive system, track system, bridge structure system and making use the interaction of the wheel/rail as the ″link″ between these systems, the study focuses on the coupling dynamic analysis of the train, the track and the bridge. Based on the summary and digestion of the predecessor′s research experiences, this article studies the coupling vibration of the train, the track and the bridge structure system on the high speed railway line. It covers the following: 1. Establishment of a more completed dynamic analysis model for cars and locomotives: the four axle car with two level suspension is used for the study and a space vibration analysis model constituting of such rigid bodies as carbody, bogie frame and wheelset is built. There are totally 31 degree of freedom, i e, 5 for the carbody and the front and rear bogie respectively, including horizontal movement, bounce, roll, pitch and yaw, 4 for each wheelset, including horizontal movement, bounce, roll and yaw. In the wheelset movement equation, the previous assumption that the wheelset always keep rigid contact with track in the car bridge coupling analysis has been corrected. The wheelset is allowed to leave the track, i e, ″jump on rail″. The degree of freedom of the wheelset has increased from horizontal movement and yaw, 2 in total, to horizontal movement, bounce, roll, and yaw, 4 in total. The degree of freedom for the car model has increased from 23 to 31. 2.Establishment of track structure dynamic analysis model of the multi layer supporting system aiming at ballasted track bridge of multiple spans for the first time: in accordance with the type and characteristics of different track structure and their models and aiming at the most common used ballasted track, the study selected the continuous elastic Eule展开更多
This paper presents series studies on the toppling mechanism by centrifuge tests and numerical simulations. Two different discrete element methods, i.e., the continuum-based discrete element method(CDEM) and the disco...This paper presents series studies on the toppling mechanism by centrifuge tests and numerical simulations. Two different discrete element methods, i.e., the continuum-based discrete element method(CDEM) and the discontinuous deformation analysis(DDA), are adopted. The modeling results show that both the methods can accurately capture the failure modes of the centrifuge tests, including three distinct zones and two failure surfaces. Comparisons are made between the physical test and numerical simulation results. The critical inclination angle of the tilting table where the slope models are fixed on can be moderately predicted by the two methods, with different degrees of precision. The error between the test results and the simulated results is within 1% for the slope models without rock-bridges by both CDEM and DDA. However, it is amplified for the staggered-joint models that simulate the rock-bridges. With DDA, the average error is about 5%, and the maximum error is up to 17%. While with CDEM, the errors for the aligned-joint models are ranged from 1% to 6%, and it is from 10% to 29% for the staggered-joint models. The two numerical methods show the capability in simulating toppling failure of blocky rock mass with and without rock-bridges. The model with rock-bridges which provides a certain bending resistance is more stable than the one without any rock-bridge. In addition, the two failure surfaces were observed, which is different from the common understanding that only one failure surface appears.展开更多
文摘Due to extensitve application of bridge structure on high speed railway line, it is necessary to consider comprehensively the common effect of the train, the track and the bridge. By forming an integrated large system including the car and locomotive system, track system, bridge structure system and making use the interaction of the wheel/rail as the ″link″ between these systems, the study focuses on the coupling dynamic analysis of the train, the track and the bridge. Based on the summary and digestion of the predecessor′s research experiences, this article studies the coupling vibration of the train, the track and the bridge structure system on the high speed railway line. It covers the following: 1. Establishment of a more completed dynamic analysis model for cars and locomotives: the four axle car with two level suspension is used for the study and a space vibration analysis model constituting of such rigid bodies as carbody, bogie frame and wheelset is built. There are totally 31 degree of freedom, i e, 5 for the carbody and the front and rear bogie respectively, including horizontal movement, bounce, roll, pitch and yaw, 4 for each wheelset, including horizontal movement, bounce, roll and yaw. In the wheelset movement equation, the previous assumption that the wheelset always keep rigid contact with track in the car bridge coupling analysis has been corrected. The wheelset is allowed to leave the track, i e, ″jump on rail″. The degree of freedom of the wheelset has increased from horizontal movement and yaw, 2 in total, to horizontal movement, bounce, roll, and yaw, 4 in total. The degree of freedom for the car model has increased from 23 to 31. 2.Establishment of track structure dynamic analysis model of the multi layer supporting system aiming at ballasted track bridge of multiple spans for the first time: in accordance with the type and characteristics of different track structure and their models and aiming at the most common used ballasted track, the study selected the continuous elastic Eule
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2014CB047006)
文摘This paper presents series studies on the toppling mechanism by centrifuge tests and numerical simulations. Two different discrete element methods, i.e., the continuum-based discrete element method(CDEM) and the discontinuous deformation analysis(DDA), are adopted. The modeling results show that both the methods can accurately capture the failure modes of the centrifuge tests, including three distinct zones and two failure surfaces. Comparisons are made between the physical test and numerical simulation results. The critical inclination angle of the tilting table where the slope models are fixed on can be moderately predicted by the two methods, with different degrees of precision. The error between the test results and the simulated results is within 1% for the slope models without rock-bridges by both CDEM and DDA. However, it is amplified for the staggered-joint models that simulate the rock-bridges. With DDA, the average error is about 5%, and the maximum error is up to 17%. While with CDEM, the errors for the aligned-joint models are ranged from 1% to 6%, and it is from 10% to 29% for the staggered-joint models. The two numerical methods show the capability in simulating toppling failure of blocky rock mass with and without rock-bridges. The model with rock-bridges which provides a certain bending resistance is more stable than the one without any rock-bridge. In addition, the two failure surfaces were observed, which is different from the common understanding that only one failure surface appears.
