scholarly journals Vertical Nonlinear Temperature Gradient and Temperature Load Mode of Ballastless Track in China

Mathematics ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 120
Author(s):  
Bin Yan ◽  
Ruiqi Cheng ◽  
Haoran Xie ◽  
Xiangmin Zhang
Keyword(s):  
Heat Exchange ◽  
Temperature Gradient ◽  
Analysis Method ◽  
Vertical Temperature ◽  
Distribution Law ◽  
Load Model ◽  
Finite Element Software ◽  
Ballastless Track ◽  
Temperature Load ◽  
Nonlinear Temperature

In the process of heat exchange with the external environment, the internal temperature of ballastless track structure presents a nonlinear distribution. The vertical temperature gradient will cause repeated warping and deformation of track slab, resulting in mortar layer separation, which will affect driving comfort and track durability. The traditional temperature field analysis method of concrete structure based on thermodynamics has the disadvantages of too many assumptions, difficult parameter selection and too much calculation of energy consumption. In this paper, based on the finite element software ANSYS, the heat exchange was transformed into the boundary condition of heat flux, which was applied to the thermodynamic analysis model to study the nonlinear temperature distribution law of ballastless track. The accuracy of the analysis method was verified by the measured data. On this basis, the regional distribution law of temperature gradient of ballastless track under different geographical coordinates and climatic conditions was studied. By adding a regional adjustment coefficient, the vertical temperature load model of ballastless track suitable for typical areas in China was proposed. The proposed temperature load model makes up for the lack of refinement of climate division and temperature load model in relevant specifications, and has strong engineering application and popularization value.

scholarly journals Influence of track line environment on the temperature field of a double-block ballastless track slab

2018 ◽  
Vol 10 (12) ◽  
pp. 168781401881232 ◽  
Author(s):  
Zhiping Zeng ◽  
Zhibin Huang ◽  
Huatuo Yin ◽  
Xiaobai Meng ◽  
Weidong Wang ◽  
...  
Keyword(s):  
Temperature Field ◽  
Solar Radiation ◽  
Temperature Gradients ◽  
Field Analysis ◽  
Analysis Model ◽  
Vertical Temperature ◽  
Railway Line ◽  
Finite Element Software ◽  
Ballastless Track ◽  
Track Slab

The heat flux density of solar radiation, received by each surface of a double-block ballastless track bed slab, is closely related to its alignment and geographical latitude. In this work, a temperature field analysis model based on experimental data, the theories of solar radiation, and boundary heat transfer is established by a CRTS-I double-block ballastless track structure using the ABAQUS finite element software to investigate the influence of different alignments and geographical latitudes of the temperature field. The horizontal and vertical temperature gradients of the ballast bed plate were found to be in the most adverse conditions when the angle αn between the normal direction of the ballastless track slab bedside surface and positive south direction was equal to 90°. The standard deviation of the overall temperature gradient of the ballast bed was found to be at lowest and standard value of the dispersion degree was highest at an αn of 90°: 14.138 and 10.446°C/m, respectively. The horizontal and vertical temperature gradients in high latitudes and coastal areas were found to be more detrimental than that in the low latitudes or inland areas. These results can provide references for how to avoid high-temperature loading during railway line selection and track design.

Numerical Modeling and Simulation Analysis of Temperature Field of Disc Brake on Trains

2011 ◽  
Vol 199-200 ◽  
pp. 1492-1495 ◽  
Author(s):  
Guo Shun Wang ◽  
Rong Fu ◽  
Liang Zhao
Keyword(s):  
Temperature Field ◽  
Temperature Gradient ◽  
High Speed ◽  
Large Scale ◽  
Working Condition ◽  
Constant Speed ◽  
Brake Disc ◽  
Disc Brake ◽  
Brake Pad ◽  
Finite Element Software

The simulation calculation on the temperature field of the disc brake system on high-speed trains under the working condition of constant speed at 50Km/h is made. A steady-state calculation model is established according to the actual geometric size of a brake disc and a brake pad, and the analog calculation and simulation on the temperature field of the brake disc and the brake pad by using the large-scale nonlinear finite element software ABAQUS are carried out. The distribution rules of the temperature field of the brake disc and the brake pad under the working condition of constant speed are made known. The surface temperature of the brake disc at friction radius is the highest, with a band distribution for temperature. There exists a temperature flex point in the direction of thickness, of which the thickness occupies 15% of that of the brake disc; due to the small volume of the brake pad, the temperature gradient of the whole brake pad is not sharp, and larger temperature gradient occurs only on the contact surface.

Optimization Design of Automobile Suspension Springs Based on BP

2010 ◽  
Vol 42 ◽  
pp. 82-85 ◽  
Author(s):  
Xiao Hui Shi ◽  
Hong Li Gao ◽  
Ming Heng Xu
Keyword(s):  
Optimization Design ◽  
Maximum Stress ◽  
Stress Model ◽  
Analysis Method ◽  
Parallel Genetic Algorithm ◽  
Distribution Law ◽  
Suspension Spring ◽  
Automobile Suspension ◽  
Stress Point ◽  
Automotive Suspension

In order to optimize the arithmetic of the automobile suspension springs, the optimization algorithm of spring stress model based on BP neural networks was proposed. The various models of suspension spring were aggregated and analyzed, the parallel genetic algorithm for the suspension springs was proposed in this paper as well. And the spring models can be optimized fast and efficiently by the algorithm. Aiming at different models, the maximum stress point and the distribution law are given by means of experimental verifications. A new stress analysis method and a new estimate rule for the design of automotive suspension springs are provided by this method.

Failure Mechanism of a Slope Anti-Sliding Pile

2013 ◽  
Vol 639-640 ◽  
pp. 593-597
Author(s):  
Lin Chen ◽  
Yong Yao ◽  
Jiong Yang ◽  
Zhao Qiang Zhang
Keyword(s):  
Finite Element ◽  
Failure Mechanism ◽  
Reduction Method ◽  
Strength Reduction ◽  
Strength Reduction Method ◽  
Analysis Method ◽  
Feasible Method ◽  
Finite Element Software ◽  
Slope Excavation ◽  
Pile Design

According to finite element strength reduction method，the article has discussed the failure mechanism of anti-sliding pile by using finite element software MIDAS /GTS ，exploration report and anti-sliding pile design data.The comparative analysis shows that the failure of anti-siding pile is contributed by the slope excavation and rainwater.The analysis method and results can provide reference significance to other anti-sliding pile design.This paper also provide a feasible method for prediction of consequence in slope excavation.

An Analytical Solution Countercurrent Heat Transfer Between Parallel Vessels With a Linear Axial Temperature Gradient

1988 ◽  
Vol 110 (3) ◽  
pp. 254-256 ◽  
Author(s):  
E. H. Wissler
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Heat Exchange ◽  
Temperature Gradient ◽  
Infinite Medium ◽  
Linear Temperature ◽  
Linear Temperature Gradient ◽  
Axial Temperature ◽  
Mixed Mean ◽  
The Difference

Presented in this paper is a solution for countercurrent heat exchange between two parallel vessels embedded in an infinite medium with a linear temperature gradient along the axes of the vessels. The velocity profile within the vessel is assumed to be parabolic. This solution describes the temperature field within the vessels, as well as in the tissue, and establishes that the intravessel temperature is not uniform, as is generally assumed to be the case. An explicit expression for the intervessel thermal resistance based on the difference between cup-mixed mean temperatures is derived.

scholarly journals Experimental Study of the Temperature Distribution in CRTS-II Ballastless Tracks on a High-Speed Railway Bridge

2020 ◽  
Vol 10 (6) ◽  
pp. 1980 ◽  
Author(s):  
Lei Zhao ◽  
Ling-Yu Zhou ◽  
Guang-Chao Zhang ◽  
Tian-Yu Wei ◽  
Akim D. Mahunon ◽  
...  
Keyword(s):  
High Temperature ◽  
Temperature Distribution ◽  
Temperature Gradient ◽  
High Speed ◽  
Railway Track ◽  
Vertical Temperature ◽  
High Speed Railway ◽  
Extreme High Temperature ◽  
Transverse Temperature ◽  
Temperature Test

To study the temperature distribution in the China Railway Track System Type II ballastless slab track on a high-speed railway (HSR) bridge, a 1:4 scaled specimen of a simply-supported concrete box girder bridge with a ballastless track was constructed in laboratory. Through a rapid, extreme high temperature test in winter and a conventional high temperature test in summer, the temperature distribution laws in the track on the HSR bridge were studied, and the vertical and transverse temperature distribution trend was suggested for the track. Firstly, the extreme high temperature test results showed that the vertical temperature and the vertical temperature difference distribution in the track on HSR bridge were all nonlinear with three stages. Secondly, the extreme high temperature test showed that the transverse temperature distribution in the track was of quadratic parabolic nonlinear form, and the transverse temperature gradient in the bottom base was significantly higher than that of the other layers of the track. Thirdly, the three-dimensional temperature distribution in the track on HSR bridge was a nonlinear, three-stage surface. Furthermore, similar regularities were also obtained in the conventional high temperature test, in which the temperature span ranges were different from those of the extreme high temperature test. In addition, the conventional high temperature test also showed that under the natural environment conditions, the internal temperature gradient in the track layers changed periodically (over a period of 24 h).

Effects of Age and Overhead Illumination on Temperatures Preferred by Underyearling Rainbow Trout, Salmo gairdneri, in a Vertical Temperature Gradient

1978 ◽  
Vol 35 (11) ◽  
pp. 1430-1433 ◽  
Author(s):  
Wen-Hwa Kwain ◽  
Robert W. McCauley
Keyword(s):  
Rainbow Trout ◽  
Temperature Gradient ◽  
Temperature Gradients ◽  
Salmo Gairdneri ◽  
Vertical Temperature Gradient ◽  
Temperature Preference ◽  
Vertical Temperature ◽  
Preferred Temperature ◽  
Distribution Of Fish ◽  
Vertical Gradients

During their first 12 mo of life rainbow trout, Salmo gairdneri, preferred progressively cooler temperatures as they grew older; 19 °C was selected during the 1st mo and the selected temperature declined by intervals of 0.5 °C for each of the following months up to the 3rd mo. Fish swam higher in temperature gradients exposed to overhead illumination than in those in total darkness. This trend was reversed during the following 9 mo. These findings demonstrate the important role that age plays in the temperature preference of this species and the influence that overhead light may have on the distribution of fish in vertical gradients. Key words: preferred temperature, age, Salmo gairdneri, light gradients

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