Assessing the fast non-Hertzian methods based on the simulation of wheel–rail rolling contact and wear distribution

2019 ◽  
Vol 234 (5) ◽  
pp. 524-537 ◽  
Author(s):  
Boyang An ◽  
Daolin Ma ◽  
Ping Wang ◽  
Jiayi Zhou ◽  
Rong Chen ◽  
...  
Keyword(s):  
Rolling Contact ◽  
Wear Depth ◽  
Royal Institute ◽  
Wear Model ◽  
Wear Performance ◽  
Normal Contact ◽  
Depth Prediction ◽  
Contact Models ◽  
Institute Of Technology ◽  
The University

This paper aims at assessing several fast non-Hertzian methods, coupled with two wear models, based on the wheel–rail rolling contact and wear prediction. Four contact models, namely Kik-Piotrowski's method, Linder's method, Ayasse-Chollet's STRIPES algorithm and Sichani's ANALYN algorithm are employed for comparing the normal contact. For their tangential modelling, two tangential algorithms, i.e. FASTSIM and FaStrip, are used. Two commonly used wear models, namely the Archard (extended at the KTH Royal Institute of Technology) and USFD (developed by the University of Sheffield based on T-gamma approach), are further utilized for wear distribution computation. All results predicted by the fast non-Hertzian methods are evaluated against the results of Kalker's CONTACT code using penetration as the input. Since the two wear models adopt different expressions for calculating the wear performance, the attention of this paper is on assessing which one is more suitable for the fast non-Hertzian methods to utilize. The comparison shows that the combination of the USFD wear model with any of the fast non-Hertzian methods agrees better with CONTACT+USFD. In general, ANALYN+FaStrip is the best solution for the simulation of the wheel–rail rolling contact, while STRIPES+FASTSIM can provide better accuracy for the maximum wear depth prediction using the USFD wear model.

scholarly journals Mutual Capacity Building through North-South Collaboration Using Challenge-Driven Education

2019 ◽  
Vol 11 (24) ◽  
pp. 7236 ◽  
Author(s):  
Anna-Karin Högfeldt ◽  
Anders Rosén ◽  
Christine Mwase ◽  
Ann Lantz ◽  
Lena Gumaelius ◽  
...  
Keyword(s):  
Engineering Education ◽  
Social Values ◽  
Organizational Structures ◽  
Royal Institute ◽  
International Policy ◽  
Education Change ◽  
Global Challenges ◽  
New Knowledge ◽  
Institute Of Technology ◽  
The University

The urgent need for actions in the light of the global challenges motivates international policy to define roadmaps for education on all levels to step forward and contribute with new knowledge and competencies. Challenge-Driven Education (CDE) is described as an education for Sustainable Development (ESD) approach, which aims to prepare students to work with global challenges and to bring value to society by direct impact. This paper describes, evaluates and discusses a three-year participatory implementation project of Challenge-driven education (CDE) within the engineering education at the University of Dar es Salam, UDSM, which has been carried out in collaboration with the Royal Institute of Technology, KTH in Stockholm. Conclusions are drawn on crucial aspects for engineering education change through the lens of Activity Theory (AT), where CDE is brought forward as a motivating ESD initiative for engineering faculty and students. Furthermore participatory co-creation is notably useful as it aims to embrace social values among the participants. Also, traditional organizational structures will need to be continuously negotiated in the light of the integration of more open-ended approaches in education.

scholarly journals Applying Two Simplified Ellipse-Based Tangential Models to Wheel-Rail Contact Using Three Alternative Nonelliptic Adaptation Approaches: A Comparative Study

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Boyang An ◽  
Ping Wang ◽  
Jiayi Zhou ◽  
Rong Chen ◽  
Jingmang Xu ◽  
...  
Keyword(s):  
Comparative Study ◽  
Computational Cost ◽  
Rolling Contact ◽  
Railway Vehicle ◽  
Normal Contact ◽  
Tangential Contact ◽  
Track Dynamics ◽  
Contact Models ◽  
Creep Force

In the modeling of railway vehicle-track dynamics and wheel-rail damage, simplified tangential contact models based on ellipse assumption are usually used due to strict limitation of computational cost. Since most wheel-rail contact cases appear to be nonelliptic shapes, a fast and accurate tangential model for nonelliptic contact case is in demand. In this paper, two ellipse-based simplified tangential models (i.e., FASTSIM and FaStrip) using three alternative nonelliptic adaptation approaches, together with Kalker’s NORM algorithm, are applied to wheel-rail rolling contact cases. It aims at finding the best approach for dealing with nonelliptic rolling contact. Compared to previous studies, the nonelliptic normal contact solution in the present work is accurately solved rather than simplification. Therefore, it can avoid tangential modeling evaluation affected by inaccurate normal contact solution. By comparing with Kalker’s CONTACT code, it shows both FASTSIM-based and FaStrip-based models can provide accurate global creep force. With regard to local rolling contact solution, only the accuracy of FaStrip-based models is satisfactory. Moreover, Ayasse-Chollet’s local ellipse approach appears to be the best choice for nonelliptic adaptation.

Comparison of calculation methods for wheel–switch rail normal and tangential contact

2016 ◽  
Vol 231 (2) ◽  
pp. 148-161 ◽  
Author(s):  
Jingmang Xu ◽  
Ping Wang ◽  
Xiaochuan Ma ◽  
Jieling Xiao ◽  
Rong Chen
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Problems ◽  
Rolling Contact ◽  
The Finite Element Method ◽  
Normal Contact ◽  
Tangential Contact ◽  
Contact Models ◽  
Railway Turnout ◽  
Element Method

Wheel–rail contact is more complex in railway a turnout than in ordinary track and, thus, necessitates an advanced model to simulate dynamic interaction and predict rail wear. The main aim of the present work is to assess the application of several wheel–rail rolling contact models in railway turnout. For normal contact problems, wheel–rail contact models based on four different methods are compared: Hertz theory, the semi-Hertzian method, CONTACT, and the finite element method. The assessment is based on the results of contact patch shape and size and contact pressure for several wheelset lateral displacements. The load is set to a constant and equal to static wheel load. Calculations are performed at the section of switch rail head with width 35 mm in CN60-1100-1:18 turnout; both standard and worn rail profiles are accounted for. For tangential contact problems, four corresponding methods are assessed, based on the calculation of creep forces, distribution of the stick/slide region and computational efficiency: Shen–Hedrick–Elkins theory, FASTSIM, improved FASTSIM based on semi-Hertzian method, and CONTACT. It is found that the normal contact problems solved by the semi-Hertzian method and CONTACT correlate well with the finite element method, and the tangential contact problems solved by improved FASTSIM and CONTACT are quite favorable. The conclusions of this work can provide some guidance for contact model selection in the dynamic simulation and wear prediction of railway turnout.

Parameter Studies for Wheel Wear Using a Flexible Wheelset

2013 ◽  
Vol 712-715 ◽  
pp. 1230-1234
Author(s):  
Na Wu ◽  
Jing Zeng
Keyword(s):  
High Speed ◽  
Wear Depth ◽  
Wheel Wear ◽  
Wear Model ◽  
Wear Performance ◽  
Flexible Wheelset ◽  
Wheel Profile ◽  
Wheel Profile Wear ◽  
Multi Body ◽  
Equivalent Conicity

In order to reduce wheel profile wear of high-speed train and extend the service life of wheels, a high-speed vehicle multi-body dynamic model and wheel profile wear model are established, in which the wheelset is considered as flexible. The influence of wheel profile, track gauge, and rail cant is extensively studied. The simulation results show that the type XP55 wheel has smallest cumulative wear depth, and type LM wheel has largest wear depth. It is known that the equivalent conicity of the wheel should not be too large or too small. The track gauge with 1435-1438mm and rail cant with 1:35-1:40 can have better wheel wear performance.

Tire Modeling by Finite Elements

1992 ◽  
Vol 20 (1) ◽  
pp. 33-56 ◽  
Author(s):  
L. O. Faria ◽  
J. T. Oden ◽  
B. Yavari ◽  
W. W. Tworzydlo ◽  
J. M. Bass ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Rolling Contact ◽  
Test Problems ◽  
State Behavior ◽  
Normal Contact ◽  
New Developments ◽  
Applied Torque ◽  
Dimensional Finite Element ◽  
Tire Modeling ◽  
Three Dimensional Finite Element

Abstract Recent advances in the development of a general three-dimensional finite element methodology for modeling large deformation steady state behavior of tire structures is presented. The new developments outlined here include the extension of the material modeling capabilities to include viscoelastic materials and a generalization of the formulation of the rolling contact problem to include special nonlinear constraints. These constraints include normal contact load, applied torque, and constant pressure-volume. Several new test problems and examples of tire analysis are presented.

Simplified Prediction of Ply Steer in Radial Tires

1980 ◽  
Vol 8 (1) ◽  
pp. 3-9 ◽  
Author(s):  
C. W. Bert
Keyword(s):  
Composite Laminate ◽  
Ground Plane ◽  
Lateral Force ◽  
Rolling Contact ◽  
Slip Angle ◽  
Uniform Stress ◽  
Rubber Composite ◽  
Laminate Theory ◽  
Contact Models ◽  
Uniform Stress State

Abstract Ply steer is a rolling contact phenomenon which manifests itself as a lateral force acting at the ground plane of a tire constrained in yaw or a change in slip angle of a tire free to yaw. It has long been known that radial tires generally exhibit greater ply steer than do bias tires. However, the only previously published quantitative analysis of this phenomenon considered the multi-layer cord-rubber composite by means of netting analysis, which is not very accurate at cord angles typical of radial tire belts. A simple, explicit expression is developed herein by combining modern composite laminate theory with two very simple, uniform-stress-state tire-road contact models. The ply-steer results predicted by the resulting expressions are compared with some experimental results and the agreement is found to be reasonably satisfactory.

INSULATION AGAINST ICE AT MEASURING WEIRS

1974 ◽  
Vol 5 (1) ◽  
pp. 32-49 ◽  
Author(s):  
JOHN TVEIT
Keyword(s):  
Hydraulic Engineering ◽  
Simple Method ◽  
Institute Of Technology ◽  
The University ◽  
Difficult Cases

This article deals with the problem of insulating measuring weirs to avoid ice disturbances. The development of a simple method for insulating a conventional V-weir is described. This method will serve its purpose in many cases. For more difficult cases a special type of a fully insulated weir is described. The experiments described were carried out by The Division of Hydraulic Engineering, The University of Trondheim, The Norwegian Institute of Technology, at the River and Harbour Laboratory of the University, and at the IHD representative basin Sagelva.

scholarly journals Simulation and Experimental Study on Wear of U-Shaped Rings of Power Connection Fittings under Strong Wind Environment

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 735
Author(s):  
Songchen Wang ◽  
Xianchen Yang ◽  
Xinmei Li ◽  
Cheng Chai ◽  
Gen Wang ◽  
...  
Keyword(s):  
Abrasive Wear ◽  
Adhesive Wear ◽  
Surface Hardness ◽  
Wear Depth ◽  
Strong Wind ◽  
Wear Model ◽  
Wind Environment ◽  
Simulation Results ◽  
Oxidation Wear ◽  
Good Agreement

The objective of this study was to investigate the wear characteristics of the U-shaped rings of power connection fittings, and to construct a wear failure prediction model of U-shaped rings in strong wind environments. First, the wear evolution and failure mechanism of U-shaped rings with different wear loads were studied by using a swinging wear tester. Then, based on the Archard wear model, the U-shaped ring wear was dynamically simulated in ABAQUS, via the Umeshmotion subroutine. The results indicated that the wear load has an important effect on the wear of the U-shaped ring. As the wear load increases, the surface hardness decreases, while plastic deformation layers increase. Furthermore, the wear mechanism transforms from adhesive wear, slight abrasive wear, and slight oxidation wear, to serious adhesive wear, abrasive wear, and oxidation wear with the increase of wear load. As plastic flow progresses, the dislocation density in ferrite increases, leading to dislocation plugs and cementite fractures. The simulation results of wear depth were in good agreement with the test value of, with an error of 1.56%.

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