Analysis of Vibration Behavior of the Elevated Track Structure

2021 ◽  
pp. 95-124
Author(s):  
Xiaoyan Lei
Keyword(s):  
Track Structure ◽  
Vibration Behavior

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

scholarly journals Mechanical Performance of a Ballastless Track System for the Railway Bridges of High-Speed Lines: Experimental and Numerical Study under Thermal Loading

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2876
Author(s):  
Yingying Zhang ◽  
Lingyu Zhou ◽  
Akim D. Mahunon ◽  
Guangchao Zhang ◽  
Xiusheng Peng ◽  
...  
Keyword(s):  
High Speed ◽  
Thermal Loading ◽  
Mechanical Performance ◽  
Track Structure ◽  
Box Girder ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Track System ◽  
Girder Bridge ◽  
Track Slab

The mechanical performance of China Railway Track System type II (CRTS II) ballastless track suitable for High-Speed Railway (HSR) bridges is investigated in this project by testing a one-quarter-scaled three-span specimen under thermal loading. Stress analysis was performed both experimentally and numerically, via finite-element modeling in the latter case. The results showed that strains in the track slab, in the cement-emulsified asphalt (CA) mortar and in the track bed, increased nonlinearly with the temperature increase. In the longitudinal direction, the zero-displacement section between the track slab and the track bed was close to the 1/8L section of the beam, while the zero-displacement section between the track slab and the box girder bridge was close to the 3/8L section. The maximum values of the relative vertical displacement between the track bed and the bridge structure occurred in the section at three-quarters of the span. Numerical analysis showed that the lower the temperature, the larger the tensile stresses occurring in the different layers of the track structure, whereas the higher the temperature, the higher the relative displacement between the track system and the box girder bridge. Consequently, quantifying the stresses in the various components of the track structure resulting from sudden temperature drops and evaluating the relative displacements between the rails and the track bed resulting from high-temperature are helpful in the design of ballastless track structures for high-speed railway lines.

Investigation on the free vibration behavior of sandwich conical shells with reinforced cores

2021 ◽  
pp. 109963622110204
Author(s):  
Mehdi Zarei ◽  
Gholamhossien Rahimi ◽  
Davoud Shahgholian-Ghahfarokhi
Keyword(s):  
Free Vibration ◽  
Orientation Angle ◽  
Element Model ◽  
Filament Winding ◽  
Vertex Angle ◽  
Sandwich Shell ◽  
Cross Sectional ◽  
Conical Shells ◽  
Vibration Behavior ◽  
Axial Forces

The free vibration behavior of sandwich conical shells with reinforced cores is investigated in the present study using experimental, analytical, and numerical methods. A new effective smeared method is employed to superimpose the stiffness contribution of skins with those of the stiffener in order to achieve equivalent stiffness of the whole structure. The stiffeners are also considered as a beam to support shear forces and bending moments in addition to the axial forces. Using Donnell’s shell theory and Galerkin method, the natural frequencies of the sandwich shell are subsequently derived. To validate analytical results, experimental modal analysis (EMA) is further conducted on the conical sandwich shell. For this purpose, a method is designed for manufacturing specimens through the filament winding process. For more validation, a finite element model (FEM) is built. The results revealed that all the validations were in good agreement with each other. Based on these analyses, the influence of the cross-sectional area of the stiffeners, the semi-vertex angle of the cone, stiffener orientation angle, and the number of stiffeners are investigated as well. The results achieved are novel and can be thus employed as a benchmark for further studies.

scholarly journals An Optimized Flutter-Driven Triboelectric Nanogenerator with a Low Cut-In Wind Speed

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 366
Author(s):  
Yang Xia ◽  
Yun Tian ◽  
Lanbin Zhang ◽  
Zhihao Ma ◽  
Huliang Dai ◽  
...  
Keyword(s):  
Power Generation ◽  
Wind Speed ◽  
Energy Harvesting ◽  
Wind Energy ◽  
Output Power ◽  
Open Circuit Voltage ◽  
Open Circuit ◽  
Triboelectric Nanogenerator ◽  
Vibration Behavior ◽  
Air Speed

We present an optimized flutter-driven triboelectric nanogenerator (TENG) for wind energy harvesting. The vibration and power generation characteristics of this TENG are investigated in detail, and a low cut-in wind speed of 3.4 m/s is achieved. It is found that the air speed, the thickness and length of the membrane, and the distance between the electrode plates mainly determine the PTFE membrane’s vibration behavior and the performance of TENG. With the optimized value of the thickness and length of the membrane and the distance of the electrode plates, the peak open-circuit voltage and output power of TENG reach 297 V and 0.46 mW at a wind speed of 10 m/s. The energy generated by TENG can directly light up dozens of LEDs and keep a digital watch running continuously by charging a capacitor of 100 μF at a wind speed of 8 m/s.

Influence of ionisation track structure on 20 nm FDSOI transistor

2021 ◽  
Vol 123 ◽  
pp. 114179
Author(s):  
Hao Zhang ◽  
Hongxia Liu ◽  
Ziwen Pan ◽  
Shupeng Chen ◽  
Ruibo Chen
Keyword(s):  
Track Structure ◽  
20 Nm

scholarly journals Deformation Law and Control Limit of CRTSIII Slab Track under Subgrade Frost Heave

2021 ◽  
Vol 11 (8) ◽  
pp. 3520
Author(s):  
Xiaopei Cai ◽  
Qian Zhang ◽  
Yanrong Zhang ◽  
Qihao Wang ◽  
Bicheng Luo ◽  
...  
Keyword(s):  
High Speed ◽  
Base Plate ◽  
Element Model ◽  
Middle Part ◽  
Railway Track ◽  
Frost Heave ◽  
Track Structure ◽  
Slab Track ◽  
Plastic Damage ◽  
Track Irregularity

In order to find out the influence of subgrade frost heave on the deformation of track structure and track irregularity of high-speed railways, a nonlinear damage finite element model for China Railway Track System III (CRTSIII) slab track subgrade was established based on the constitutive theory of concrete plastic damage. The analysis of track structure deformation under different subgrade frost heave conditions was focused on, and amplitude the limit of subgrade frost heave was put forward according to the characteristics of interlayer seams. This work is expected to provide guidance for design and construction. Subgrade frost heave was found to cause cosine-type irregularities of rails and the interlayer seams in the track structure, and the displacement in lower foundation mapping to rail surfaces increased. When frost heave occured in the middle part of the track slab, it caused the greatest amount of track irregularity, resulting in a longer and higher seam. Along with the increase in frost heave amplitude, the length of the seam increased linearly whilst its height increased nonlinearly. When the frost heave amplitude reached 35 mm, cracks appeared along the transverse direction of the upper concrete surface on the base plate due to plastic damage; consequently, the base plate started to bend, which reduced interlayer seams. Based on the critical value of track structures’ interlayer seams under different frost heave conditions, four control limits of subgrade frost heave at different levels of frost heave amplitude/wavelength were obtained.

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