Vibration Characteristics of Discretely-Supported Floating Slab Track Under Moving Load

Author(s):  
Qiang Huang ◽  
Hongwei Huang ◽  
Dongmei Zhang
2011 ◽  
Vol 97-98 ◽  
pp. 3-9
Author(s):  
Yang Wang ◽  
Quan Mei Gong ◽  
Mei Fang Li

The slab track is a new sort of track structure, which has been widely used in high-speed rail and special line for passenger. However, the ballastless track structure design theory is still not perfect and can not meet the requirements of current high-speed rail and passenger line ballastless track. In this paper, composite beam method is used to calculate the deflection of the track plate and in this way the vertical supporting stress distribution of the track plate can be gotten which set a basis for the follow-up study of the dynamic stress distribution in the subgrade. Slab track plate’s bearing stress under moving load is analyzed through Matlab program. By calculation and analysis, it is found that the deflection of track plate and the rail in the double-point-supported finite beam model refers to the rate of spring coefficient of the fastener and the mortar.The supporting stress of the rail plate is inversely proportional to the supporting stress of the rail. The two boundary conditions of that model ,namely, setting the end of the model in the seams of the track plate or not , have little effect on the results. We can use the supporting stress of the track plates on state 1to get the distribution of the supporting stress in the track plate when bogies pass. Also, when the dynamic load magnification factor is 1.2, the track plate supporting stress of CRST I & CRST II-plate non-ballasted structure is around 40kPa.


2008 ◽  
Vol 317 (3-5) ◽  
pp. 1017-1034 ◽  
Author(s):  
Chen-Ming Kuo ◽  
Cheng-Hao Huang ◽  
Yi-Yi Chen

Author(s):  
Longxiang Ma ◽  
Weining Liu

A numerical model based on the periodic-Fourier-modal method is proposed for the dynamic analysis of a train-floating slab track coupling system with random track irregularity. In the model, each vehicle of the train is modeled as a multiple-degree-of-freedom vibration system consisting of one car body, two bogies, four wheelsets, and two groups of spring-damper suspension devices. The floating slab track is modeled as a periodic-infinite structure with discrete supports and discontinuous slabs. Linear springs are used to couple the train and the track. In order to establish this numerical model, an efficient periodic approach named periodic-Fourier-modal method for solving the dynamic response of the floating slab track under a harmonic moving load is first developed. Based on this, a strategy is then proposed which can couple the moving train to the track with random irregularity and express the wheel–rail force as a superposition of a series of harmonic loads. With the solved wheel–rail force, the vehicle response can be directly calculated through vehicle dynamics, while track response can be calculated through the principle of superposition and the reuse of the initially proposed periodic-Fourier-modal method. Using this train–floating slab track coupling model, the solution of the dynamic response of the infinite track can be transformed to perform only within a single periodic range, which can save the calculation time significantly. The numerical results of the Beijing subway, based on the proposed model, are discussed in detail, and some important conclusions are drawn.


2020 ◽  
Vol 58 (6) ◽  
pp. 760
Author(s):  
Kien Dinh Nguyen

Vibration of two-directional functionally graded sandwich (2D-FGSW) Timoshenko beams under a moving harmonic load is investigated. The beams consist of three layers, a homogeneous core and two functionally graded skin layers with the material properties continuously varying in both the thickness and length directions by power functions. A finite element formulation is derived and employed to compute the vibration characteristics of the beams. The obtained numerical result reveals that the material inhomogeneity and the layer thickness ratio play an important role on the natural frequencies and dynamic response of the beams. A parametric study is carried out to highlight the effects of the power-law indexes, the moving load speed and excitation frequency on the vibration characteristics of the beams.  The influence of the beam aspect ratio on the vibration of the beams is also examined and discussed. 


2018 ◽  
Vol 23 (No 3, September 2018) ◽  
Author(s):  
Hongliang Li ◽  
Bo Zhang ◽  
Yunxuan Gong ◽  
Donghua Wang

With the continuous development of industry, variable-section beams and high speed moving loads with large mass are widely used. Thus, it is of great significance to study the vibration response of variable-section beam with the consideration of inertia effect. Most past research focuses on the vibration response on uniform beams considering inertial effects, but there is little research on the vibration response of moving loads on variable section beam considering the inertia effect. In this paper, a variable section beam is simplified as a multi-stage ladder beam. Using the Euler-Bernoulli beam model, free-vibration characteristics and forced vibration characteristics of cantilever ladder beam are analysed. Following this step the vibration response considering the influence of the inertia effect is studied and compared with the situation that does not consider the influence of inertia effect. The results show that the mass, velocity, and acceleration of moving loads influence the effect of inertia on the response. Mass is the main factor affecting the results. The inertia effect caused by the acceleration and velocity can be ignored when the mass of moving load is small. The results have good engineering applicability.


Author(s):  
Bolong Jiang ◽  
Meng Ma ◽  
Minghang Li ◽  
Weining Liu ◽  
Teng Li

In railway turnout areas, vertical and horizontal structure irregularities, including geometry and stiffness, result in vibration amplification during the passage of trains. These vibrations can then spread to the surrounding environment. A steel spring floating slab track may be used to control such vibrations, especially in metro-type urban railways. An experimental study was conducted to investigate the vibration-mitigating effects of the floating slab track in turnout areas, and the results were compared with the performance of a regular slab track. Four test cases (consisting of six test sections) were selected: a floating slab track in the turnout zone (consisting of a switch rail section and a nose rail section), a floating slab track in the plain line, a slab track in the turnout zone (consisting of a switch rail section and a nose rail section), and a slab track in the plain line. The vibration characteristics of the floating slab track in the plain line and in the turnout were calculated to explain the test results. The test results indicate that when trains pass across the floating slab track in the turnout zone, the vertical vibration response is close to the horizontal response on the switch rail sections. The use of floating slab track can effectively reduce this vertical vibration. However, the vertical vibration response is much larger than the horizontal response on the nose rail sections of the turnout zone. When the floating slab track is used in these turnout zones, the vertical vibration of the rail decreases while the horizontal vibration increases. Compared to sections using the regular slab track in the turnout zone, the vibration of the floating slab track segments in the turnout zone is shown to be exacerbated, although the vibration level at the adjacent tunnel wall is effectively reduced.


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