Numerical simulation and parameterisation of rail–wheel normal contact

2016 ◽  
Vol 231 (4) ◽  
pp. 419-430 ◽  
Author(s):  
Jacobus L Cuperus ◽  
Gerhard Venter
Keyword(s):  
Finite Element ◽  
Boundary Element ◽  
Maximum Error ◽  
Hertzian Contact ◽  
Test Case ◽  
Empirical Equations ◽  
Finite Element Analyses ◽  
Contact Parameter ◽  
Normal Contact ◽  
Power Law Equation

This investigation aims to find empirical equations that describe the rail–wheel normal (frictionless) contact characteristics. These equations can then be used to determine an equivalent Hertzian load to account for normal contact in the finite element analyses mandated by the Transnet RS/ME/SP/008 specification, without explicitly simulating the contact between two bodies. The standard is similar to UIC 510-5 and does not consider tangential contact. The normal contact problem is solved for the test case using nonlinear finite element methods as well as the boundary element method. Material plasticity was also investigated in finite element analyses with limited effect for contact away from the flange area. The data from boundary element analyses were fitted to a power law equation for each contact parameter. The equivalent Hertzian contact produced with the empirical equations is able to predict the normal contact parameters relatively accurately, producing a maximum error of 9.6% (excluding one area with a geometric anomaly).

Combined finite element-boundary element method modelling of elastic multi-asperity contacts

2009 ◽  
Vol 223 (5) ◽  
pp. 767-776 ◽  
Author(s):  
S Ilincic ◽  
G Vorlaufer ◽  
P A Fotiu ◽  
A Vernes ◽  
F Franek
Keyword(s):  
Finite Element ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Hertzian Contact ◽  
Multilayer Systems ◽  
Influence Coefficients ◽  
Asperity Contacts ◽  
First Time ◽  
Element Algorithm ◽  
Element Method

A novel formulation of elastic multi-asperity contacts based on the boundary element method (BEM) is presented for the first time, in which the influence coefficients are numerically calculated using a finite element method (FEM). The main advantage of computing the influence coefficients in this manner is that it makes it also possible to consider an arbitrary load direction and multilayer systems of different mechanical properties in each layer. Furthermore, any form of anisotropy can be modelled too, where Green's functions either become very complicated or are not available at all. The rest of the contact analysis is then performed applying a custom-developed boundary element algorithm. The scheme was tested by considering the frictionless contact between a flat surface and a sphere. The obtained results are in good agreement with the analytical solution known for a Hertzian contact. Applied to either a frictionless or a frictional contact between real surfaces of different samples, our FEM-BEM method has shown that the composite roughness of surfaces in contact uniquely determines the contact pressure distribution.

scholarly journals FEM-based wear simulation for fretting contacts

2020 ◽  
Vol 53 (1) ◽  
pp. 20-27
Author(s):  
Antti Mäntylä ◽  
Janne Juoksukangas ◽  
Jouko Hintikka ◽  
Tero Frondelius ◽  
Arto Lehtovaara
Keyword(s):  
Finite Element ◽  
Contact Stiffness ◽  
Simulation Method ◽  
Test Case ◽  
Wear Simulation ◽  
Real Component ◽  
Normal Contact ◽  
Tangential Contact ◽  
Contact Formulation ◽  
Full Coupling

This article presents a robust Finite-Element-Method-based wear simulation method, particularly suitable for fretting contacts. This method utilizes the contact subroutine in a commercial finite element solver Abaqus. It is based on a user-defined contact formulation for both normal and tangential directions. For the normal contact direction, a nodal gap field is calculated by using a simple Archard's wear equation to describe the depth of material removal due to wear. The wear field is included in the contact pressure calculation to allow simulation of wear and contact stress evolution during the loading cycles. The main advantage of this approach is that all contact variables are accessible inside the routine, which allows full coupling between normal and tangential contact variables. Also, there is no need for mesh modifications during the solution. This makes the implementation flexible, robust and particularly suitable for fretting cases where friction and tangential contact stiffness play an essential role. The method is applied to the bolted joint type fretting test case. The methodology is also fully applicable to complex real component simulations.

On the Frictional Characteristics of Ball Bearings Coated With Solid Lubricants

1999 ◽  
Vol 121 (4) ◽  
pp. 761-767 ◽  
Author(s):  
M. R. Lovell ◽  
M. M. Khonsari
Keyword(s):  
Finite Element ◽  
Friction Force ◽  
Normal Load ◽  
Transversely Isotropic ◽  
Solid Lubricants ◽  
Operating Conditions ◽  
Hertzian Contact ◽  
Ball Bearings ◽  
Normal Contact ◽  
Low Speed

The problem of a ball bearing in normal contact between two transversely isotropic coated substrates is investigated using the finite element method (FEM). A three-dimensional finite element model is developed that accurately determines the steady friction force in low-speed bearing systems containing soft layered solid lubricant films. Extensive numerical results, which are verified using Hertzian contact theory and laboratory experiments, are obtained at 540 operating conditions by varying coating material, coating thickness, normal load, ball material, and ball radius. Friction force results generated from the FEM are normalized by introducing the dimensionless transversely isotropic coating parameter, ξ. A numerical expression for the normalized friction force in coated ball bearings is determined by curvefitting the results of the 540 simulations performed. The relevance of such an expression, as related to the durability of low-speed bearings, is subsequently ascertained and discussed.

Simulation of Fretting Wear in Half-Plane Geometries—Part II: Analysis of the Transient Wear Problem Using Quadratic Programming

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
D. Nowell
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Analytical Solution ◽  
Quadratic Programming ◽  
Fretting Wear ◽  
Hertzian Contact ◽  
Partial Slip ◽  
Finite Element Analyses ◽  
Element Analysis ◽  
Computationally Expensive

This paper presents an efficient numerical method based on quadratic programming, which may be used to analyze fretting contacts in the presence of wear. The approach provides an alternative to a full finite element analysis, and is much less computationally expensive. Results are presented for wear of a Hertzian contact under full sliding and under partial slip. These are compared with previously published finite element analyses of the same problem. Results are also obtained for the fully worn problem by allowing a large number of wear cycles to accumulate. The predicted traction distributions for this case compare well with the fully worn analytical solution presented in part one of this paper.

Performance enhancement of normal contact ratio gearing system through correction factor

2019 ◽  
Vol 13 (3) ◽  
pp. 5242-5258
Author(s):  
R. Ravivarman ◽  
K. Palaniradja ◽  
R. Prabhu Sekar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Correction Factor ◽  
Bending Strength ◽  
Performance Enhancement ◽  
Transmission Ratio ◽  
Contact Ratio ◽  
Element Analysis ◽  
Normal Contact ◽  
Root Region

As lined, higher transmission ratio drives system will have uneven stresses in the root region of the pinion and wheel. To enrich this agility of uneven stresses in normal-contact ratio (NCR) gearing system, an enhanced system is desirable to be industrialized. To attain this objective, it is proposed to put on the idea of modifying the correction factor in such a manner that the bending strength of the gearing system is improved. In this work, the correction factor is modified in such a way that the stress in the root region is equalized between the pinion and wheel. This equalization of stresses is carried out by providing a correction factor in three circumstances: in pinion; wheel and both the pinion and the wheel. Henceforth performances of this S+, S0 and S- drives are evaluated in finite element analysis (FEA) and compared for balanced root stresses in parallel shaft spur gearing systems. It is seen that the outcomes gained from the modified drive have enhanced performance than the standard drive.

Application of the Boundary Element Method and Modal Analysis to Tire Acoustics Problems

1993 ◽  
Vol 21 (2) ◽  
pp. 66-90 ◽  
Author(s):  
Y. Nakajima ◽  
Y. Inoue ◽  
H. Ogawa
Keyword(s):  
Finite Element ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Acoustic Radiation ◽  
Traffic Noise ◽  
Noise Prediction ◽  
Prediction System ◽  
Tire Noise ◽  
Acoustic Contribution ◽  
Element Method

Abstract Road traffic noise needs to be reduced, because traffic volume is increasing every year. The noise generated from a tire is becoming one of the dominant sources in the total traffic noise because the engine noise is constantly being reduced by the vehicle manufacturers. Although the acoustic intensity measurement technology has been enhanced by the recent developments in digital measurement techniques, repetitive measurements are necessary to find effective ways for noise control. Hence, a simulation method to predict generated noise is required to replace the time-consuming experiments. The boundary element method (BEM) is applied to predict the acoustic radiation caused by the vibration of a tire sidewall and a tire noise prediction system is developed. The BEM requires the geometry and the modal characteristics of a tire which are provided by an experiment or the finite element method (FEM). Since the finite element procedure is applied to the prediction of modal characteristics in a tire noise prediction system, the acoustic pressure can be predicted without any measurements. Furthermore, the acoustic contribution analysis obtained from the post-processing of the predicted results is very helpful to know where and how the design change affects the acoustic radiation. The predictability of this system is verified by measurements and the acoustic contribution analysis is applied to tire noise control.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

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