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.

Comparison of non-Hertzian modeling approaches for wheel–rail rolling contact mechanics in the switch panel of a railway turnout

2018 ◽  
Vol 233 (4) ◽  
pp. 466-476 ◽  
Author(s):  
Xiaochuan Ma ◽  
Ping Wang ◽  
Jingmang Xu ◽  
Rong Chen
Keyword(s):  
Contact Problems ◽  
Rolling Contact ◽  
Head Width ◽  
Stick Slip ◽  
Normal Contact ◽  
Tangential Contact ◽  
Modeling Approaches ◽  
Contrast Analysis ◽  
Slip Region ◽  
Contact Relation

Due to the complicated wheel–rail contact relation of railway turnouts, it is necessary to select a reasonable rolling contact model to simulate the vehicle–turnout dynamics and wheel–rail damages. This paper mainly aims to evaluate the calculation accuracy and efficiency of different non-Hertzian modeling approaches in solving normal and tangential wheel–rail contact problems of railway turnouts. Four different non-Hertzian approaches, namely CONTACT, Kik–Piotrowski, Ayasse–Chollet, and Sichani methods are compared and analyzed. The above four models are built considering the relative motion of stock/switch rails. A wheel profile called LMA contacting with stock/switch rails (head width 35 mm) of CN60-1100-1:18 turnouts is selected as the object of analysis. The normal contact problems are evaluated by the wheel–rail contact areas, shapes, and normal contact pressures. The assessment of tangential contact problems is based on the creep curves, tangential contact stresses, and distribution of the stick/slip region. In addition, a contrast analysis is performed on the calculation efficiencies of the four approaches. It is found that the normal and tangential contact results calculated based on the Sichani method coincide well with those obtained according to CONTACT, and the calculation efficiency is about 262 times that of CONTACT. The conclusions can provide some guidance to the selection of wheel–rail rolling contact approach in the simulation of vehicle–turnout dynamics and wheel–rail damages.

An Investigation Into Effect of Train Curving on Wear and Contact Stresses of Wheel and Rail

2008 ◽  
Author(s):  
Xuesong Jin ◽  
Jun Guo ◽  
Xinbiao Xiao ◽  
Zefeng Wen
Keyword(s):  
Numerical Method ◽  
Contact Stress ◽  
Great Influence ◽  
Contact Stresses ◽  
Rolling Contact ◽  
Railway Vehicle ◽  
Normal Contact Stress ◽  
Normal Contact ◽  
Rail Wear ◽  
Curved Track

Some important papers concerning the studies on rail wear and wheel/rail contact stresses are reviewed. The present paper utilizes a numerical method to analyze the effect of railway vehicle curving on the wear and contact stresses of wheel/rail. The numerical method considers a combination of Kalker’s non-Hertzian rolling contact theory, a material wear model and a vertical and lateral coupling dynamics model of a half vehicle and a curved track. The present analysis investigates the influence of the curving speed, the curved track super-elevation and the rail cant on the wear and the contact stresses. Through the detailed numerical analysis, it is found that the maximum contact stress depends greatly not only on the curving speed but also on the profiles of the wheel/rail. The curving speed increasing leads to increase the normal load of the wheel rolling over the high curved rail, but, decrease the normal contact stress level under the condition of the optimum match of wheel/rail profiles. The track super elevation increasing efficiently lowers the contact stresses and the wear at a constant curving speed. The rail cant has a great influence on the low rail wear of the curved track. Increasing the rail cant leads to the great growth of the low curved rail wear, the reduction in the high rail wear. The results are very useful in the maintenance of the track.

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.

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.

scholarly journals Micromechanism of the Breakage of Two Spherical Gypsum Particles under Normal–Tangential Contact Conditions

2021 ◽  
Vol 11 (9) ◽  
pp. 4039
Author(s):  
Yiran Niu ◽  
Lin Li ◽  
Yanwei Zhang ◽  
Shicai Yu ◽  
Jian Zhou
Keyword(s):  
Tangential Force ◽  
Coarse Grained ◽  
Spherical Particles ◽  
Contact Conditions ◽  
Normal Contact ◽  
Tangential Contact ◽  
Theoretical Predictions ◽  
Tangential Forces ◽  
Predicted Values ◽  
The Relationship

Contact breakage of particles makes a large difference in the strength of coarse-grained soils, and exploring the characteristics within the process of the breakage is of great significance. Ignoring the influence of particle shape, the micromechanism of two spherical particles breaking under normal–tangential contact conditions was investigated theoretically and experimentally. Through theoretical analysis, the breakage form, the shape and size of the conical core, and the relationship between the normal and tangential forces at crushing were predicted. Particle contact tests of two gypsum spheres were carried out, in which the breakage forms, features of the conical cores and the normal and tangential forces at crushing were recorded for comparison with the predicted values. The test results and the theoretical predictions showed good agreement. Both the analysis and test demonstrate that the presence of tangential forces causes the conical core to assume the shape of an oblique cone, and the breakage form to change. Moreover, with increasing normal contact force, the tangential force needed for crushing increases gradually first and then decreases suddenly.

On the Importance of Displacement History in Soft-Body Contact Models

2015 ◽  
Vol 11 (4) ◽  
Author(s):  
Jonathan Fleischmann ◽  
Radu Serban ◽  
Dan Negrut ◽  
Paramsothy Jayakumar
Keyword(s):  
Frictional Contact ◽  
Local Deformation ◽  
Friction Model ◽  
Direct Shear ◽  
Nonpenetration Condition ◽  
Time Step ◽  
Tangential Contact ◽  
Direct Shear Tests ◽  
Contact Models ◽  
Contact Displacement

Two approaches are commonly used for handling frictional contact within the framework of the discrete element method (DEM). One relies on the complementarity method (CM) to enforce a nonpenetration condition and the Coulomb dry-friction model at the interface between two bodies in mutual contact. The second approach, called the penalty method (PM), invokes an elasticity argument to produce a frictional contact force that factors in the local deformation and relative motion of the bodies in contact. We give a brief presentation of a DEM-PM contact model that includes multi-time-step tangential contact displacement history. We show that its implementation in an open-source simulation capability called Chrono is capable of accurately reproducing results from physical tests typical of the field of geomechanics, i.e., direct shear tests on a monodisperse material. Keeping track of the tangential contact displacement history emerges as a key element of the model. We show that identical simulations using contact models that include either no tangential contact displacement history or only single-time-step tangential contact displacement history are unable to accurately model the direct shear test.

Contact Stiffness Parameters for Finite Element Modeling of Contact

2019 ◽  
Vol 799 ◽  
pp. 211-216
Author(s):  
Alina Sivitski ◽  
Priit Põdra
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Contact Stiffness ◽  
Influential Factors ◽  
Element Analysis ◽  
Normal Contact ◽  
Element Modeling ◽  
Contact Models ◽  
Machine Elements ◽  
Normal Contact Pressure

Contact modeling could be widely used for different machine elements normal contact pressure calculations and wear simulations. However, classical contact models as for example Hertz contact models have many assumptions (contact bodies are elastic, the contact between bodies is ellipse-shaped, contact is frictionless and non-conforming). In conditions, when analytical calculations cannot be performed and experimental research is economically inexpedient, numerical methods have been applied for solving such engineering tasks. Contact stiffness parameters appear to be one of the most influential factors during finite element modeling of contact. Contact stiffness factors are usually selected according to finite element analysis software recommendations. More precise analysis of contact stiffness parameters is often required for finite element modeling of contact.

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