Numerical analysis of the effect of track parameters on the wear of turnout rails in high-speed railways

2016 ◽  
Vol 232 (3) ◽  
pp. 709-721 ◽  
Author(s):  
Jingmang Xu ◽  
Ping Wang ◽  
Jian Wang ◽  
Boyang An ◽  
Rong Chen
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
High Speed ◽  
Numerical Procedure ◽  
Dynamic Interaction ◽  
Operating Conditions ◽  
Rolling Contact ◽  
Wear Model ◽  
Rail Wear ◽  
Railway Turnout

In this study, a numerical procedure is developed to predict the wear of turnout rails, and the effect of track parameters is investigated. The procedure includes simulation of the dynamic interaction between the train and the turnout, the rolling contact analysis, and the wear model. The dynamic interaction is simulated with the validated commercial software Simpack that uses a space-dependent model of a railway turnout. To reproduce the actual operating conditions of a railway turnout, stochastic variations in the input parameters are considered in the simulation of the dynamic interaction. The rolling contact is analyzed with the semi-Hertzian method and improved FASTSIM algorithm, which enable the contact model to deal with situations of multipoint contact and nonelliptic contact. Based on the Archard’s wear law, the wear model requires the calculation of normal/tangential stresses and a relative slide on the contact patches. The numerical procedure is performed for the selected sections of the vehicle, which runs through the railway turnout in the diverging route. By using the numerical procedure, the effect of track parameters (track gage, rail inclination, and friction coefficient) on the wear of turnout rails is analyzed. The results show that the wear of the front wheelset is more serious than the wear of the rear wheelset for a single vehicle. The degree of wear of switch rails is more severe than that of the stock rails and the difference is more obvious for the front wheelset of the switch rails. The wear of switch rails is mainly concentrated on the rail gage corner, while the wear of stock rails is mainly concentrated on the rail crown. For the analysed CN60-1100-1:18 turnout and the high-speed vehicle CRH2 in China, the rail wear rate could be slowed down by increasing the track gage and decreasing the rail inclination. Alternatively, the rail wear rate could be slowed by decreasing the friction coefficient; however, the variation of wear depth is quite small for friction coefficients that are larger than 0.3.

Numerical prediction of the development of rail wear on high-speed railways

2019 ◽  
Vol 234 (9) ◽  
pp. 927-944
Author(s):  
Pu Wang ◽  
Shuguo Wang ◽  
Liang Gao
Keyword(s):  
High Speed ◽  
Numerical Prediction ◽  
Operating Conditions ◽  
Rolling Contact ◽  
Wear Depth ◽  
Curve Section ◽  
High Speed Railway ◽  
Rail Wear ◽  
The Difference ◽  
Circular Curve

In this paper, a numerical prediction model was established to investigate the development of rail wear on high-speed railways, and a corresponding program was written using Matlab. According to Archard’s material wear theory, the wear depth distribution in the wheel–rail contact patch and along the rail profile was calculated based on a simulation of vehicle–track dynamics and a wheel–rail rolling contact analysis. In the dynamics model, various structural components and the complex nonlinear interactions between components were precisely simulated to ensure consistency with reality. Simulations were then conducted for every possible load case, and dimensionless weight factors were introduced to model the diverse operating conditions of a high-speed railway. An adaptive step algorithm was adopted to iteratively update the rail profile and reduce cumulative deviation or errors, improving the stability and reliability of the numerical model. Finally, a case study was conducted to investigate the development of wear in different track sections on a high-speed railway using the developed model. The results indicated that in the circular curve and transition sections, the side wear of the outer rail was obvious, and the wear of the inner rail was relatively smaller and mostly distributed in the middle of the railhead. The wear of the outer rail was more severe in the circular curve section compared to that in the transition sections. The closer to the rail shoulder, the greater the difference between the wear in the circular curve section and that in the transition section. In the tangent section, the wear of both rails was similarly distributed in the middle of the railhead and far less severe than in either the circular curve or transition sections. The agreement between the calculated results and field observations verified the rationality of the established rail wear model, which shows promise for improving the maintenance planning of high-speed railways and furthering the understanding of the rail wear processes.

A Cobalt Diffusion Based Model for Predicting Crater Wear of Carbide Tools in Machining Titanium Alloys

2005 ◽  
Vol 127 (1) ◽  
pp. 136-144 ◽  
Author(s):  
Jiang Hua ◽  
Rajiv Shivpuri
Keyword(s):  
Wear Rate ◽  
Titanium Alloys ◽  
High Speed ◽  
Cutting Tools ◽  
Interface Temperature ◽  
Wear Model ◽  
Crater Wear ◽  
Wear Rates ◽  
Process Comparison ◽  
Thermally Driven

In machining titanium alloys with cemented carbide cutting tools, crater wear is the predominant wear mechanism influencing tool life and productivity. An analytical wear model that relates crater wear rate to thermally driven cobalt diffusion from cutting tool into the titanium chip is proposed in this paper. This cobalt diffusion is a function of cobalt mole fraction, diffusion coeficient, interface temperature and chip velocity. The wear analysis includes theoretical modeling of the transport-diffusion process, and obtaining tool–chip interface conditions by a nonisothermal visco-plastic finite element method (FEM) model of the cutting process. Comparison of predicted crater wear rate with experimental results from published literature and from high speed turning with WC/Co inserts shows good agreement for different cutting speeds and feed rate. It is seen that wear rates are independent of cutting time.

Wheel/Rail Contact Geometry of Different Wheel Tread Profile in High-Speed Railway Turnout

2011 ◽  
Vol 255-260 ◽  
pp. 3988-3992 ◽  
Author(s):  
Rong Chen ◽  
Wang Ping ◽  
Yang Song
Keyword(s):  
High Speed ◽  
Dynamic Interaction ◽  
Longitudinal Distribution ◽  
Key Factors ◽  
Heavy Load ◽  
High Speed Railway ◽  
Equivalent Conicity ◽  
Railway Turnout ◽  
Safety And Stability ◽  
Vertical Impact

Train/turnout dynamic interaction is exacerbated by high speed of passenger train and heavy load of freight train, and wheel/rail relation is one of the key factors that determine the running characteristics of the train. Focusing on three types of wheel treads with different profiles (TB tapered tread, LM worn tread, LMA worn tread), longitudinal distribution of the contact geometric parameters along the switch rail and nose rail of 350km/h No.18 turnout are calculated, such as tread equivalent conicity, coefficient of contact angle difference, roll angle factor, gravitational stiffness of wheelset, gravitational angle stiffness of wheelset, etc. Results show that: (1) LMA worn tread produces the smallest irregularity; (2) wheel/rail vertical impact at the frog will become bigger; (3) Top profile of switch rail and nose rail should be designed according to the wheel tread type so as to mitigate the wheel/rail dynamic interaction and increase the safety and stability of a train.

Hardness matching of rail/wheel steels for high-speed-train based on wear rate and rolling contact fatigue performance

2019 ◽  
Vol 6 (6) ◽  
pp. 066501 ◽  
Author(s):  
Xiaojiao Shi ◽  
Qingzhi Yan ◽  
Xiaoxin Zhang ◽  
Guijiang Diao ◽  
Chenchen Zhang ◽  
...  
Keyword(s):  
Wear Rate ◽  
High Speed ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Fatigue Performance ◽  
High Speed Train

Wheel–rail low adhesion issues and its effect on wheel–rail material damage at high speed under different interfacial contaminations

2019 ◽  
Vol 233 (15) ◽  
pp. 5477-5490 ◽  
Author(s):  
Bing Wu ◽  
Boyang An ◽  
Zefeng Wen ◽  
Wenjian Wang ◽  
Tao Wu
Keyword(s):  
High Speed ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Rolling Contact ◽  
Experimental Results ◽  
Test Rig ◽  
Adhesion Mechanism ◽  
Numerical Investigations ◽  
Rail Wear ◽  
Adhesion Condition

The objective of this paper is to ascertain the wheel–rail low adhesion mechanism using a high-speed wheel–rail rolling contact test rig under different interfacial contaminations. Based on the experimental results, a numerical method was proposed to investigate the wheel–rail wear and rolling contact fatigue due to low adhesion issues. The experimental results indicated that the wheel–rail low adhesion phenomena can happen under interfacial liquid contaminations, especially at high-speed running condition. Preliminary numerical investigations showed that the low adhesion condition can easily lead to sliding hence serious wear, especially at the speed between 160 km/h and 200 km/h. The temperature rise within the contact patch can be significantly more severe once wheel and rail are in full slip, causing rolling contact fatigue due to material softening.

Correlation between Carbon Fibres/Carbon Nanotubes Fillers and Wear Behaviour of Poly(ether-ether-ketone) Composite

2015 ◽  
Vol 808 ◽  
pp. 113-118
Author(s):  
Dan Catalin Trufasu ◽  
Maria Aida Cristina Besnea ◽  
Adrian Cotet ◽  
Gabriel Andrei
Keyword(s):  
Carbon Nanotubes ◽  
Friction Coefficient ◽  
Carbon Fiber ◽  
Wear Rate ◽  
Operating Conditions ◽  
Wear Behaviour ◽  
Ether Ether Ketone ◽  
Peek Composite ◽  
Poly Ether Ether Ketone ◽  
Ether Ketone

The wear behaviour of poly (ether-ether-ketone) (PEEK) composite was investigated according to the load and test speed. Three types of materials were studied: first, neat PEEK, PEEK with 30 wt. % carbon fiber (PEEK CF30), and third, PEEK with carbon nanotubes (PEEK ELS NANO). Tribological tests were performed on the universal tribometer UMT-2, using a pin-on-disc device. The friction coefficient and wear rate for the composites studied were analysed. Tests carried out have allowed the examination of the influence of load and speed on the friction coefficient and wear rate under dry sliding regime. Also, structural changes were noticed by optical and SE microscopy, and wear types of surface were discussed. As a result of experimental tests, it was established that PEEK composite with carbon fiber/carbon nanotubes exhibit good wear behaviour under operating conditions.

Experimental Research of Scuffing of Friction Pair

2014 ◽  
Vol 697 ◽  
pp. 254-257
Author(s):  
Jie Lin Xu ◽  
Zeng Xiong Peng ◽  
Nan Wang ◽  
Shan Lin Xu
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
High Speed ◽  
Friction And Wear ◽  
Friction Pair ◽  
Common Phenomenon ◽  
Working Pressure ◽  
Wear Characteristics ◽  
Worn Surface ◽  
Friction And Wear Characteristics

The scuffing of friction pair is a common phenomenon in conditions of high speed and pressure. It was researched on scuffing characteristics in this paper. By using UMT-3 friction and wear tester, the friction and wear characteristics of slipper pair material in hydraulic component were investigated, and the friction coeficient-speed curves in the different pressures were got, as well as the wear rate-speed curves. The worn surface morphology of pin specimen was photographed by SEM, and the formation mechanism of the worn surface was analyzed. The results suggested that: friction coefficient and wear rate would have a jump when the scuffing occurred, the friction and wear characteristics would be affected by the interaction of pressure (P) and speed (V) . The PV characteristic restricted the correlation between working pressure and speed.

Simulation of Tool Wear in Prestressed Cutting Superalloys

2016 ◽  
Vol 836-837 ◽  
pp. 402-407
Author(s):  
Rui Tao Peng ◽  
Jing Li ◽  
Xin Zi Tang ◽  
Zhuan Zhou
Keyword(s):  
Finite Element ◽  
Wear Rate ◽  
Tool Wear ◽  
High Speed ◽  
Cutting Temperature ◽  
Cutting Parameters ◽  
Tool Geometry ◽  
Wear Model ◽  
Element Analysis ◽  
Wear Calculation

In high speed machining superalloys processes, tool wear is strongly influenced by the cutting temperature and contact stresses. Finite element analysis of machining can be used as a supplementary to the physical experiment, this paper provides investigations in 2D and 3D finite element modeling and simulation of prestressed cutting for GH4169 superalloy, a tool wear model for the specified tool and workpiece pair is developed based on the Usui's wear model, furthermore, tool temperature, wear rate and nodal displacement on the face of tool in prestressed cutting of superalloy is analyzed under various prestress condition and cutting parameters, and Python language is adopted to modify the Abaqus code used to allow tool wear calculation and tool geometry updating. The results of the simulation indicate that the tool wear rate increases with the increase of cutting time, and the influence of the prestress to tool wear in prestressed cutting process of shaft part is unremarkable.

Tribological properties of pyrolytic carbon in high-speed tests

2020 ◽  
pp. 71-75
Author(s):  
V. A. Khorev ◽  
V. I. Rumyantsev ◽  
G. A. Ponomarenko ◽  
A. S. Osmakov ◽  
V. N. Fischev
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
High Speed ◽  
Tribological Behavior ◽  
Pyrolytic Carbon ◽  
Extreme Conditions ◽  
Friction Units ◽  
The Difference

The friction units of modern power turbines require the use of special materials with a stable and low coefficient of friction in extreme conditions. The most successfully used for these purposes are antifriction carbon-graphite materials, in particular isotropic pyrolytic carbon. It is established that isotropic pyrolytic carbon has a lower friction coefficient and wear rate than ATG-S antifriction graphite. Based on the analysis of the microstructure and fractograms of wear traces, it was suggested that the difference in the tribological behavior of materials is caused by various mechanisms of material destruction. It is also shown that isotropic pyrolytic carbon tends to decrease the wear rate and friction coefficient with increasing density. Ill. 7. Ref. 10. Tab. 1.

Determination of Creep Force, Moment, and Work Distribution in Rolling Contact With Slip

1989 ◽  
Vol 111 (4) ◽  
pp. 711-718 ◽  
Author(s):  
Bor-Tsuen Wang ◽  
Robert H. Fries
Keyword(s):  
Rolling Contact ◽  
Wear Model ◽  
Contact Patch ◽  
Rail Wear ◽  
Work Distribution ◽  
Force Moment ◽  
Creep Force ◽  
Rigid Body Motions ◽  
Work Done

Investigators interested in the wear of wheels and rails frequently use a wear model that postulates wear is proportional to the work done in the contact patch. Most investigators compute the work using the rigid body motions of the wheel and the total creepage at the contact patch. Such an approach gives an overall or integrated measure of the wear in the contact patch. In previous wheel/rail wear work, we have assumed the wear to be distributed parabolically across the contact patch. In order to check this assumption and to permit refinement of our wear modeling technique, we desired to know the distribution of work within the contact patch. In order to compute the work distribution within the contact patch, we must be able to compute the distributions of both the creep force and the creepage. This paper describes a method of computing lateral and longitudinal creep force and creep moment distributions within the contact patch for combined rolling and slip conditions. It also describes the computations of creep distributions within the contact patch. The work distribution is computed from the dot product of force and creepage. The method uses Kalker’s simplified theory to determine the force and creepage distributions. The actual computations are made using a modification of Kalker’s program FASTSIM. A by-product of the work is the determination of the adhesion and slip regions for arbitrary creepage conditions.

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