scholarly journals Mapping Relation between Rail and Bridge Deformation Considering Nonlinear Contact of Interlayer

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6653
Author(s):  
Leixin Nie ◽  
Lizhong Jiang ◽  
Wangbao Zhou ◽  
Yulin Feng
Keyword(s):  
Elastic Modulus ◽  
Theoretical Model ◽  
High Speed ◽  
Structural Deformation ◽  
Track Structure ◽  
Vertical Deformation ◽  
Element Analysis ◽  
Stationary Potential ◽  
Vertical Stiffness ◽  
Nonlinear Contact

This paper examines the effect of structural deformation on the unit slab-type ballastless track structure of high-speed railway. The principle of stationary potential energy was used to map the relation between girder vertical deformation and rail deformation considering the effect of subgrade boundary conditions and the nonlinear contact of interlayer. The theoretical model was verified by comparing with the finite element analysis and experimental results. The theoretical model was used to analyze the effects of several key parameters on the rail deformation, such as vertical deformation amplitude, elastic modulus of the mortar layer, and vertical stiffness of the fasteners. The results show that the track slabs suffered significant disengagement, which makes the deformation of the track structure at the position of the beam joint tend to be gentle when nonlinear contact between the mortar layer and the track slabs was considered. The track slabs disengagement mainly occurs near the beam joints (the side of the deformed beam). As the deflection amplitude of the girder increases, the track deformation, the fastener forces and the disengagement length of the track slabs are obviously nonlinear. When the vertical stiffness of the fastener and/or the elastic modulus of the mortar layer increase, the fastener force and the track plate disengagement length increase monotonically and nonlinearly, which will adversely affect the life and safety of the track structure.

Experimental Study on Vertical Stiffness of WJ-8 Fastener for High-Speed Railway

2015 ◽  
Vol 723 ◽  
pp. 100-103 ◽  
Author(s):  
Can Liu ◽  
Zhi Ping Zeng ◽  
Jia Yu Yuan ◽  
Bin Wu ◽  
Kun Teng Zhu
Keyword(s):  
High Speed ◽  
Plate Theory ◽  
Vertical Displacement ◽  
Track Structure ◽  
Static Stiffness ◽  
Analysis Model ◽  
Element Analysis ◽  
Vertical Stiffness ◽  
Slab Track ◽  
Ballastless Track

The rail vertical displacement of CRTSII slab track structure under vertical static loads was analyzed in this paper by using 1:1 full-scale track model, based on which the WJ-8 fastener vertical static stiffness was calculated, and the rationality of the fastener vertical stiffness values and the relationship between the values and load were studied. According to the beam-plate theory and beam-solid theory for slab ballastless track, a finite element analysis model of CRTSII slab track structure was established. The rail vertical displacement under the same case as test was calculated by using the measured fastener vertical stiffness value. The rationality of the method for testing and the fastener vertical static stiffness is verified through comparing the calculated values with experimental ones.

Thermo-stress coupling field of friction lining during high-speed slide of wire rope in a mine friction-drive hoist

2011 ◽  
Vol 226 (9) ◽  
pp. 2154-2167 ◽  
Author(s):  
Yu-xing Peng ◽  
Zhen-cai Zhu ◽  
Min-ming Tong ◽  
Guo-an Chen ◽  
Yan-hai Cheng ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Contact Zone ◽  
Constitutive Relation ◽  
High Speed ◽  
Thermomechanical Properties ◽  
Element Analysis ◽  
Coupling Field ◽  
Zone Ii ◽  
Coefficient Of Linear Expansion ◽  
Friction Lining

In order to seek the intrinsic reason for the serious high-speed slide accident in a mine hoist, the thermo-stress coupling field of friction lining was studied during the high-speed slide. First, the helical contact characteristics were analysed. Subsequently, the thermomechanical properties and the dynamic coefficient of linear expansion were studied, and the thermomechanical constitutive relation was obtained. Then, the theoretical model of thermo-stress was established with the consideration of the helical contact characteristics and the thermomechanical constitutive relation. Also, the numerical simulation was performed by the finite element analysis. Finally, the experiment was carried out on a friction tester. It is found that the temperature is the highest at the contact zone II and the friction heat focuses on the contact surface layer. The variation frequency of the stress is 6.98 Hz at 0.5 m/s. Besides, the catastrophe for the strain and coefficient of friction occurs at 3 m/s. The thermo-stress concentration occurs at contact zone II. The experiment results agree with the simulation ones, which validates the theoretical model of thermo-stress.

The Finite Element Analysis of the Floor Damper of High Speed Train

2015 ◽  
Vol 740 ◽  
pp. 142-145
Author(s):  
Dong Zhe Wang ◽  
Jian Min Ge ◽  
Xian Kui Zeng ◽  
Zong Ting Zhang ◽  
Chong Lv
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Physical Model ◽  
Correction Factor ◽  
High Speed ◽  
Vertical Deformation ◽  
High Speed Train ◽  
Element Analysis ◽  
Model Experiments ◽  
The Finite Element Analysis

In this paper, based on the honeycomb floor damper of high-speed train, the finite element analysis was carried out on the floor damper, and we compared the experimental results with the physical model experiments. The results show that: when correction factor γ = 0.5, there is the minimum incremental error of vertical deformation, and the value of the damper parameters is the best at this time.

Mapping the relationship between the structural deformation of a simply supported beam bridge and rail deformation in high-speed railways

2019 ◽  
Vol 234 (10) ◽  
pp. 1081-1092 ◽  
Author(s):  
Lizhong Jiang ◽  
Lan Zheng ◽  
Yulin Feng ◽  
Zhipeng Lai ◽  
Wangbao Zhou
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Structural Deformation ◽  
Vertical Stiffness ◽  
Deformation Curves ◽  
Subsidence Zone ◽  
Minimum Potential ◽  
Track Bridge ◽  
Beam Bridge ◽  
Analytical Expressions

By considering the effect of the constraints of the rails on the subgrade section on both sides of a bridge, analytical expressions are derived to study the mapping relationship between the rail deformation and changes in the condition of the supporting beam(s), based on the principle of minimum potential energy. Rail deformations in a slab track–bridge system induced by the subsidence of piers and beam faults are investigated in detail. Results are compared with the finite element calculations to assess the main factors that influence rail deformation. The results show that the rail deformation curves under different working conditions (single or multiple pier subsidence and beam faults) determined using the analytical model fit well with those from the finite element models. With increasing subsidence of piers, the rail deformed more significantly in the subsidence zone. Moreover, both the maximum downward and upward deformations of the rail changed linearly with the subsidence of piers. Use of fasteners or a mortar layer with greater vertical stiffness caused the rail to become more irregular.

Performance analysis of magnetic gear with Halbach array for high power and high speed

2020 ◽  
Vol 64 (1-4) ◽  
pp. 959-967
Author(s):  
Se-Yeong Kim ◽  
Tae-Woo Lee ◽  
Yon-Do Chun ◽  
Do-Kwan Hong
Keyword(s):  
Permanent Magnet ◽  
Eddy Current ◽  
High Power ◽  
High Speed ◽  
Torque Ripple ◽  
Eddy Current Loss ◽  
Element Analysis ◽  
Current Loss ◽  
Halbach Array ◽  
Magnetic Gear

In this study, we propose a non-contact 80 kW, 60,000 rpm coaxial magnetic gear (CMG) model for high speed and high power applications. Two models with the same power but different radial and axial sizes were optimized using response surface methodology. Both models employed a Halbach array to increase torque. Also, an edge fillet was applied to the radial magnetized permanent magnet to reduce torque ripple, and an axial gap was applied to the permanent magnet with a radial gap to reduce eddy current loss. The models were analyzed using 2-D and 3-D finite element analysis. The torque, torque ripple and eddy current loss were compared in both models according to the materials used, including Sm2Co17, NdFeBs (N42SH, N48SH). Also, the structural stability of the pole piece structure was investigated by forced vibration analysis. Critical speed results from rotordynamics analysis are also presented.

Tribological and dynamical analysis of a brake pad with multiple blocks for a high-speed train

2019 ◽  
Vol 234 (11) ◽  
pp. 1771-1788
Author(s):  
YK Wu ◽  
JL Mo ◽  
B Tang ◽  
JW Xu ◽  
B Huang ◽  
...  
Keyword(s):  
High Speed ◽  
Wear Behavior ◽  
Dynamical Analysis ◽  
Brake Disc ◽  
Brake Pad ◽  
High Speed Train ◽  
Brake Squeal ◽  
Element Analysis ◽  
Single Block ◽  
Middle Ring

In this research, the tribological and dynamical characteristics of a brake pad with multiple blocks are investigated using experimental and numerical methods. A dynamometer with a multiblock brake pad configuration on a brake disc is developed and a series of drag-type tests are conducted to study the brake squeal and wear behavior of a high-speed train brake system. Finite element analysis is performed to derive physical explanations for the observed experimental phenomena. The experimental and numerical results show that the rotational speed and braking force have important influences on the brake squeal; the trends of the multiblock and single-block systems are different. In the multiblock brake pad, the different blocks exhibit significantly different magnitudes of contact stresses and vibration accelerations. The blocks located in the inner and outer rings have higher vibration acceleration amplitudes and stronger vibration energies than the blocks located in the middle ring.

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.

Dynamic Analysis of DVG 850 High-Speed Machining Center

2012 ◽  
Vol 487 ◽  
pp. 203-207
Author(s):  
Gong Xue Zhang ◽  
Xiao Kai Shen
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Response Analysis ◽  
Improved Method ◽  
Analysis Software ◽  
Element Analysis ◽  
Harmonic Response ◽  
Machining Center ◽  
Calculation Results ◽  
Harmonic Response Analysis

Purpose, with the application of workbench finite element analysis software, get the analysis results of DVG 850 high-speed vertical machining center via the modal analysis and harmonic response analysis. Use the calculation results for reference, put forward the improved method, and prove the credibility of the simulation analysis by testing DVG 850 prototype.

Localization simulation of forming-induced residual stresses of composite using prescribed boundary

2021 ◽  
pp. 073168442094118
Author(s):  
Qi Wu ◽  
Hongzhou Zhai ◽  
Nobuhiro Yoshikawa ◽  
Tomotaka Ogasawara ◽  
Naoki Morita
Keyword(s):  
Residual Stresses ◽  
Representative Volume Element ◽  
Computational Cost ◽  
Volume Element ◽  
Thermoplastic Composite ◽  
Structural Deformation ◽  
Element Analysis ◽  
Micro Scale ◽  
Representative Volume ◽  
Localization Approach

A novel localization approach that seamlessly bridges the macro- and micro-scale models is proposed and used to model the forming-induced residual stresses within a representative volume element of a fiber reinforced composite. The approach uses a prescribed boundary that is theoretically deduced by integrating the asymptotic expansion of a composite and the equal strain transfer, thus rendering the simulation setting to be easier than conventional approaches. When the localization approach is used for the finite element analysis, the temperature and residual stresses within an ideal cubic representative volume element are precisely simulated, given a sandwiched thermoplastic composite is formed under one-side cooling condition. The simulation results, after being validated, show that the temperature gradient has an impact on the local residual stresses, especially on the in-plane normal stress transverse to the fiber, and consequently, influences the structural deformation. This newly designed localization approach demonstrates the advantages of enhanced precision and reduced computational cost owing to the fast modeling of the finely meshed representative volume element. This is beneficial for a detailed understanding of the actual residual stresses at the micro-scale.

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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