Prediction of the Thermal Stability of Wheel Under Frequent Braking for Urban Rail Vehicle

2010 ◽  
Author(s):  
Zhizhuang Yu ◽  
Yong Wang ◽  
Jianyong Zuo ◽  
Bin Han ◽  
Leilei Gu
Keyword(s):  
Thermal Stability ◽  
Three Dimensional ◽  
Element Model ◽  
Urban Rail Transit ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Brake Shoe ◽  
Urban Rail ◽  
Electric Braking ◽  
Thermal Stability Of

A train is braked to stop when it reaches every station in an urban rail transit network. The combination of electro-pneumatic braking is currently adopted for many trains in China. The electric braking is manipulated prior to pneumatic braking. In the case of electric braking failure, the pneumatic braking device will then be used to perform ultimate protection. A typical pneumatic braking device includes a wheel and brake shoe. The work status of the wheel will certainly affect the running of train in frequent braking. In this paper, the authors established a three-dimensional finite element model (FEM) of wheel to simulate the three-dimensional transient temperature fields of the wheel at different running velocities and braking deceleration conditions. In addition, we analyzed the thermal stability of the wheel. Finally, we calculated the safety-related running velocity and braking deceleration. The results of the calculation are aimed to provide useful guidance for the urban rail operation in Chinese major cities. We recommend that the urban train speed should be lower than 60km/h when only the pneumatic braking device is used for braking.

Study on Welding Deformations of Shipboard of Container Vessel

2011 ◽  
Vol 488-489 ◽  
pp. 218-221
Author(s):  
Hong Li ◽  
Da Lu Qiu ◽  
Guang Lei Li ◽  
Hui Long Ren
Keyword(s):  
Heat Flux ◽  
Heat Source ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Plastic Strains ◽  
Out Of Plane ◽  
Inherent Strain ◽  
Nonlinear Behaviors ◽  
Plane Deformations

Residual plastic strains of the shipboard are the product of nonlinear behaviors during welding. Deformations of a welded shipboard injure the beauty of appearance of the ship, cause errors during the assembly of the shipboard and reduce the strength of the ship. Residual welding deformations of shipboard of a container vessel are studied in this paper. Nonlinear three dimensional transient temperature fields are analyzed by FEM first. The heat source is modeled as a moving heat flux following a Gaussian distribution. Then, applying the equivalent loads induced by the inherent strain on the shipboard, the final in-plane shrinkage and out-of-plane deformations are calculated. Being compared with the experimental results of deformations, the simulated results show mostly conformity.

Study on the Longitudinal Horizontal Stiffness Limited Value of 20m Simply Supported Beam Pier Top of Urban Rail Transit

2014 ◽  
Vol 501-504 ◽  
pp. 1129-1135
Author(s):  
Xian Xing Dai ◽  
Ting Lin Liu ◽  
Zhen Wei Xiong ◽  
Ping Wang
Keyword(s):  
Element Model ◽  
Relative Displacement ◽  
Urban Rail Transit ◽  
Rail Transit ◽  
Simply Supported Beam ◽  
Double Line ◽  
Simply Supported ◽  
Urban Rail ◽  
Bending Mode ◽  
Common Application

Considering the common application of the 20m simply supported beam in modern urban rail transit, an integrative rail-bridge-pier finite element model is developed. The force imposed on the pier, abutment and rail are calculated in different conditions, including the bridge stretching, bending and braking. In addition, the displacement of pier top and the maximum rapid relative displacement between girder and track are also calculated. The results are shown as follows: in terms of multiple span simply supported beams, the most harmful bending mode is when the load distributes on two adjacent simply supported beams. According to the additional braking tension force, as well as the additional braking pressure and the rapid relative displacement between girder and track, the most harmful breaking mode can be confirmed respectively. In the paper, the minimum value of the longitudinal horizontal linear stiffness of 20m simply supported beam piers is 120 kN/cm (double-line).

Thermomechanical Design of a Heat Exchanger for a Recuperative Aeroengine

2006 ◽  
Vol 128 (4) ◽  
pp. 736-744 ◽  
Author(s):  
Harald Schoenenborn ◽  
Ernst Ebert ◽  
Burkhard Simon ◽  
Paul Storm
Keyword(s):  
Thermal Analysis ◽  
Heat Exchanger ◽  
Boundary Conditions ◽  
Stress Analysis ◽  
Element Model ◽  
Automatic Generation ◽  
Temperature Fields ◽  
Transient Temperature ◽  
Engine Operation ◽  
Aero Engines

Within the framework programs of the EU for Efficient and Environmentally Friendly Aero-Engines (EEFEA) MTU has developed a highly efficient cross-counter flow heat exchanger for the application in intercooled recuperated aeroengines. This very compact recuperator is based on the profile tube matrix arrangement invented by MTU and one of its outstanding features is the high resistance to thermal gradients. In this paper the combined thermomechanical design of the recuperator is presented. State-of-the-art calculation procedures for heat transfer and stress analysis are combined in order to perform a reliable life prediction of the recuperator. The thermal analysis is based upon a 3D parametric finite element model generation. A program has been generated, which allows the automatic generation of both the material mesh and the boundary conditions. Assumptions concerning the boundary conditions are presented as well as steady state and transient temperature results. The stress analysis is performed with a FEM code using essentially the same computational grid as the thermal analysis. With the static temperature fields the static loading of the profile tubes is determined. From transient thermal calculations successive 3D temperature fields are obtained which enable the determination of creep life and LCF life of the part. Finally, vibration analysis is performed in order to estimate the vibration stress of the profile tubes during engine operation. Together with the static stress a Goodman diagram can be constructed. The combined analysis shows the high life potential of the recuperator, which is important for economic operation of a recuperative aero-engine.

Analytical Solution of Transient Three-Dimensional Temperature Field in a Rotating Cylinder Subject to a Localized Laser Beam

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Mostafa M. Kashani ◽  
Mohammad R. Movahhedy ◽  
Mohammad T. Ahmadian ◽  
Reza Shoja Razavi
Keyword(s):  
Temperature Field ◽  
Analytical Solution ◽  
Analytical Model ◽  
Material Removal ◽  
Three Dimensional ◽  
Element Model ◽  
Rotating Cylinder ◽  
Transient Temperature ◽  
Analytical Scheme ◽  
Temperature Filed

Laser-assisted machining (LAM) is a growing trend in machining of hard to cut materials. In most experimental cases, LAM is carried out in two stages; first, laser and machine parameters are tuned to adjust the temperature at the material removal point (Tmr), and second, the cutting tool is engaged to cut the points that have already been heated by the laser. Alternatively, an analytical model for the prediction of temperature filed can replace lengthy experimentation needed for tuning the material removal temperature. This paper presents an analytical solution to the transient temperature field in a rotating cylinder subject to a localized laser heat source based on Green's functions. The analytical solution is validated by comparing the surface point temperatures to thermal experiments on DIN 1.7225 steel, which shows good agreement in trend and values. Furthermore, a finite element model is developed and verified by the results of the same experiments, providing a more detailed investigation on the performance of the analytical model. The developed analytical scheme can be used to readily calculate pointwise temperatures on workpiece surface and internal points which can be used as a tool for designing machining conditions.

Crystal structure, magnetic, fluorescent, electrochemical properties and thermal stability of a new copper(II) coordination polymer [Cu2(C5H4NCOO)2(C7H5N4)2]n

2015 ◽  
Vol 70 (4) ◽  
pp. 215-219 ◽  
Author(s):  
Wei Li ◽  
Chang-Hong Li ◽  
Ying-Qun Yang ◽  
Heng-Feng Li
Keyword(s):  
Crystal Structure ◽  
Thermal Stability ◽  
Coordination Polymer ◽  
Electrochemical Properties ◽  
Three Dimensional ◽  
Antiferromagnetic Interaction ◽  
Electrode Reactions ◽  
Dimensional Network ◽  
Binuclear Structure ◽  
Thermal Stability Of

AbstractA new copper(II) coordination polymer [Cu2(C5H4NCOO)2(C7H5N4)2]n (1) has been synthesized with 4-pyridinecarboxylate and 3-(pyridin-2-yl)-1,2,4-triazolyl ligands. The crystal structure shows that two neighboring copper(II) ions are coordinated with two deprotonated (anionic) 3-(pyridin-2-yl)-1,2,4-triazole ligands to form a binuclear structure. Adjacent binuclear units are linked by 4-pyridinecarboxylate anions to form a three-dimensional network structure. The magnetic, fluorescent, and electrochemical properties and thermal stability of 1 were studied. The results show that 1 exhibits antiferromagnetic interaction, and upon excitation at 318 nm, it has an intense fluorescent emission at approximately 430 nm. The electron transfer of 1 is irreversible in electrode reactions. The thermogravimetric analysis shows that 1 is stable below 240 °C.

scholarly journals A New 3D Coordination Polymer of Bismuth with Nicotinic AcidN-Oxide

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Farzin Marandi ◽  
Ingo Pantenburg ◽  
Gerd Meyer
Keyword(s):  
Crystal Structure ◽  
Thermal Stability ◽  
Coordination Polymer ◽  
Three Dimensional ◽  
Water Molecules ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Thermal Stability Of

The new three-dimensional coordination polymer {[Bi(NNO)2(NO3)]·1.5H2O}n(1, NNO−= nicotinateN-oxide) was synthesized and characterized by elemental analysis, IR and1H-NMR spectroscopy, as well as single-crystal X-ray diffraction analysis.1crystallizes in the monoclinic space group C2/c. The crystal structure consists of a rectangular-shaped grid constructed with NNO linkers. Cavities of a diameter of 7.9–8.3 Å2are filled with disordered water molecules. The thermal stability of the compound was evaluated by thermogravimetric analysis.

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