Wear Prediction in Wheel-Rail Contact under Partial Slip Conditions

2014 ◽  
Vol 658 ◽  
pp. 317-322 ◽  
Author(s):  
George Gavrila ◽  
Spiridon Cretu ◽  
Marcelin Benchea
Keyword(s):  
Numerical Model ◽  
Normal Force ◽  
Rolling Contact ◽  
Experimental Results ◽  
Partial Slip ◽  
Initial Condition ◽  
Dynamic Effects ◽  
Stick Slip ◽  
Slip Conditions ◽  
Slip Phenomenon

This paper presents a numerical model to calculate wear during rolling contact due to micro-slip. Having as initial condition a corrugated rail it is shown the influence of the corrugation wavelength and the dynamic effects of the normal force on the wear creation. Experimental results are presented in order to reveal the influence of roughness when studying the stick-slip phenomenon.

scholarly journals FRICTION ANALYSIS IN CASE OF THE CARRIAGE- FEED SHAFT CINEMATIC COUPLING AT CNC LATHE

2020 ◽  
Vol 7 (5) ◽  
pp. 30-37
Author(s):  
Daniel Popescu
Keyword(s):  
Mathematical Model ◽  
Rational Design ◽  
Normal Force ◽  
Stick Slip ◽  
Disturbing Force ◽  
Dimensional Precision ◽  
Cnc Lathe ◽  
Elastic Systems ◽  
Friction Analysis ◽  
Slip Phenomenon

The paper presents a mathematical model for analysis of friction between the tool bearing saddle and conductor at CNC lathe. The analysis of longitudinal advance movement laws is performed taking into account the appearance and development of disturbing harmonic forces created by auto-vibrations determined by the interaction between the partial elastic systems of tool and workpiece. The friction force is emphasized as product of two components depending on the sliding speed and on the normal disturbing force. By establishing the dynamic response of the system, when the normal force depends linearly on speed, acceleration and mobile ensemble position, the premises are created for stability analysis of the friction movement, obtaining the limit speeds under which the stick-slip phenomenon occurs. Thus, it is provided for a rational design of CNC lathe elastic structure, in order to improve the surface quality and the dimensional precision.

Influence of Partial Slip Conditions on Rolling Contact Fatigue of 1070 Steel

2008 ◽  
Vol 44-46 ◽  
pp. 911-916
Author(s):  
Li Juan Lu ◽  
Xiao Gui Wang ◽  
Li Jian Zhuang ◽  
Zeng Liang Gao ◽  
Y.Y. Jiang
Keyword(s):  
Rolling Contact Fatigue ◽  
Contact Process ◽  
Contact Fatigue ◽  
Normal Pressure ◽  
Multiaxial Fatigue ◽  
Rolling Contact ◽  
Cyclic Plasticity ◽  
Partial Slip ◽  
Slip Conditions ◽  
Tangential Traction

Partial slip rolling contact was analyzed in this paper by the finite element method with the application of a robust cyclic plasticity model. The repeated rolling contact process was carried out by translating the normal pressure and the tangential traction across the contact surface step by step. The normal pressure and the tangential traction were applied to the nodes through the time-dependant amplitude functions as the concentrated nodal forces. With the detailed stress-strain responses output from the FE analysis, a general multiaxial fatigue criterion was used to predict fatigue initiation life and initiation position. The influences of partial slip conditions on the residual stresses, residual shear strain and the initiation lives are obtained.

scholarly journals Investigating pull-out characteristics of tubular fabrics with different tightnesses in drilling and sampling process

2018 ◽  
Vol 69 (05) ◽  
pp. 375-380
Author(s):  
DING ZUOWEI ◽  
YU WEIDONG
Keyword(s):  
Experimental Results ◽  
Testing System ◽  
Stick Slip ◽  
Pull Out ◽  
Sampling Process ◽  
Initial Stage ◽  
Slip Phenomenon

In this paper, the pull-out characteristics of tubular fabrics with four different tightnesses were investigated via our self-designed pull-out testing system. Meanwhile, the principle of stick-slip phenomenon during the drilling and sampling process was clarified. Experimental results obtained from this system indicated that pull-out force of tubular fabrics presented a tendency of rising in the initial stage then decreasing, and finally tended towards a constant non-zero value. It also revealed that the bigger the tightnesses of tubular fabrics are, the larger its bearable force is. Moreover, the concept of smoothness coefficient was introduced to further understand the degree of difficulty that tubular fabrics pulled out from round pipe. The calculations showed that smaller tightnesses gave better smoothness performance, and naturally the smoothness coefficient was bigger.

Elastic-Plastic Finite Element Analysis of Partial Slip Rolling Contact

2001 ◽  
Vol 124 (1) ◽  
pp. 20-26 ◽  
Author(s):  
Biqiang Xu ◽  
Yanyao Jiang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Shear Strain ◽  
Contact Surface ◽  
Rolling Contact ◽  
Slip Condition ◽  
Cyclic Plasticity ◽  
Partial Slip ◽  
Stick Slip ◽  
Elastic Plastic

The finite element model with the implementation of a robust cyclic plasticity theory was used to simulate the elastic-plastic stresses for the partial slip (stick-slip) line rolling contact. Detailed rolling contact stresses and strains were obtained for up to 40 rolling passes. The partial slip condition greatly affects the residual stress in the rolling direction and the residual shear strain within a thin layer of material near the contact surface. The residual stress in the axial direction was not significantly influenced by the partial slip condition. An increase in friction coefficient drives the location of maximum shear strain to the contact surface. In addition, a comparison was made between the finite element results and the results obtained from an approximate method.

Modeling Tangential Contact of Rough Surfaces With Elastic- and Plastic-Deformed Asperities

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Dong Wang ◽  
Chao Xu ◽  
Qiang Wan
Keyword(s):  
Rough Surface ◽  
Normal Load ◽  
Experimental Results ◽  
Partial Slip ◽  
Tangential Load ◽  
Stick Slip ◽  
Normal Contact ◽  
Tangential Contact ◽  
Bilinear Relation ◽  
Proposed Model

A new tangential contact model between a rough surface and a smooth rigid flat is proposed in this paper. The model considers the contribution of both elastically deformed asperities and plastically deformed asperities to the total tangential load of rough surface. The method combining the Mindlin partial slip solution with the Hertz solution is used to model the contact formulation of elastically deformed asperities, and for the plastically deformed asperities, the solution combining the fully plastic theory of normal contact with the bilinear relation between the tangential load and deformation developed by Fujimoto is implemented. The total tangential contact load is obtained by Greenwood and Williamson statistical analysis procedure. The proposed model is first compared to the model considering only elastically deformed asperities, and the effect of mean separation and plasticity index on the relationship between the tangential load and deformation is also investigated. It is shown that the present model can be used to describe the stick–slip behavior of the rough surface, and it is a more realistic-based model for the tangential rough contact. A comparison with published experimental results is also made. The proposed model agrees very well with the experimental results when the normal load is small, and shows an error when the normal load is large.

Influence of Stick-Slip Behavior on Friction and Wear under Fretting Conditions

2006 ◽  
Vol 326-328 ◽  
pp. 1189-1192
Author(s):  
Sung Hoon Jeong ◽  
Seok Ju Yong ◽  
Tae Shik Ahn ◽  
Young Ze Lee
Keyword(s):  
Friction And Wear ◽  
Fretting Wear ◽  
Partial Slip ◽  
Dissipated Energy ◽  
Stick Slip ◽  
Steel Surfaces ◽  
Low Amplitude ◽  
Fretting Damage ◽  
Friction And Wear Characteristics ◽  
Slip Phenomenon

Friction and wear characteristics between two steel surfaces under fretting condition are investigated experimentally. The fretting damage caused by low-amplitude oscillatory sliding can be classified into three regimes of gross-slip, mixed-slip and partial-slip due to stick-slip phenomenon. One of the most important characteristics of fretting wear is the transition from gross-slip to mixed-slip. This study was focused on getting the degree of stick-slip out of the friction transition under fretting condition. Fretting wear is divided into three conditions of gross-slip/mixed-slip/ partial-slip. The criteria for the division are friction and displacement amplitude, wear scar morphology and dissipated energy. In this test, friction force and displacement were measured for detecting the transition from mixed-slip to gross-slip and qualitatively predicting the degree of the wear.

Effects of Frequency on the Fretting Conditions in a Contact Between PMMA and a Rigid Counterface

1998 ◽  
Vol 120 (4) ◽  
pp. 729-736 ◽  
Author(s):  
A. Krichen ◽  
M. Kharrat ◽  
A. Chateauminois
Keyword(s):  
Numerical Simulations ◽  
Experimental Analysis ◽  
Dynamic Modulus ◽  
Normal Load ◽  
Displacement Amplitude ◽  
Partial Slip ◽  
Tangential Load ◽  
Stick Slip ◽  
Slip Conditions

The effects of frequency on the fretting conditions in a glass/PMMA contact have been investigated using experimental analysis and numerical simulations. For partial slip conditions, the changes in the shape of the fretting cycles giving the tangential load as a function of the imposed displacement have been interpreted on the basis of changes in the dynamic modulus of the PMMA as a function of frequency. Using the numerical simulations, the values of the PMMA’s modulus at the various frequencies were determined from the analysis of the fretting cycles. For gross slip conditions, the emphasis was placed on the determination of the range of velocity associated with stick-slip processes. This information has been summarized in a fretting map giving the initial fretting condition as a function of normal load, displacement amplitude, and frequency.

Modeling tangential contact based on non-Gaussian rough surfaces

2018 ◽  
Vol 233 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Wanglong Zhan ◽  
Ping Huang
Keyword(s):  
Rough Surfaces ◽  
Load Capacity ◽  
Experimental Results ◽  
Practical Significance ◽  
Partial Slip ◽  
Stick Slip ◽  
Tangential Contact ◽  
Tangential Stiffness ◽  
Negative Skewness ◽  
Non Gaussian

A stick-slip tangential contact model between rough surfaces was proposed in this paper. The Mindlin partial slip solution for elastic contact and the double linear formulation developed by Fujimoto for plastic contact in conjunction with the Coulomb dry friction law were used to derive tangential contact formulas. Pearson system of frequency curves was used to generate non-Gaussian random surfaces. Effects of skewness and kurtosis on normal and tangential contact responses were studied independently. The results showed that negative skewness predicted lower mean separation for a given normal force and greater tangential stiffness, while for positive skewness, there exist different trends from negative skewness. With the increase of kurtosis, the load capacity and tangential stiffness decreased. The practical significance of these findings is that it can help engineers to design proper surface textures based on their requirements. A comparison of initial tangential stiffness between predicted results and published experimental results was made. The results well agreed with the experimental results when the non-Gaussian surface effects were taken into consideration.

scholarly journals A Numerical Model for Solving Three-Dimensional Rolling Contact Problems with Elastic Coating Layers

2021 ◽  
Vol 69 (4) ◽  
Author(s):  
Yinhu Xi ◽  
Marcus Björling ◽  
Andreas Almqvist
Keyword(s):  
Numerical Model ◽  
Rolling Contact Fatigue ◽  
Three Dimensional ◽  
Contact Fatigue ◽  
Contact Problems ◽  
Rolling Contact ◽  
Three Dimensional Model ◽  
Stick Slip ◽  
Influence Coefficients ◽  
Traction Distribution

AbstractIn this work, a numerical model is proposed for three-dimensional rolling contact problems with one or two elastic layers, and the tangential contact solution is emphasized. Previous works on this topic have mostly been two-dimensional, in which only longitudinal creepage has been considered. With the three-dimensional model presented in this work, all possible creepages, such as the longitudinal, lateral and spin creepages are taken into account. In order to improve the calculation efficiency, the conjugate gradient method and the FFT technique are employed. The influence coefficients for displacement and stress are obtained from the corresponding frequency response functions. The numerical results are validated against existing results and good agreement can be found. The effects of the different layers’ thicknesses and elastic moduli under different creepage combinations on the traction distribution and stick/slip results are investigated. It can be seen that by adjusting the layer parameters the traction and stick/slip results can be modified significantly, and it may, therefore, be very useful information for improving the rolling contact fatigue and mitigating wear problems in various mechanical systems. Graphical Abstract

scholarly journals Thermochemical Heat Storage in a Lab-Scale Indirectly Operated CaO/Ca(OH)2 Reactor—Numerical Modeling and Model Validation through Inverse Parameter Estimation

2021 ◽  
Vol 11 (2) ◽  
pp. 682
Author(s):  
Gabriele Seitz ◽  
Farid Mohammadi ◽  
Holger Class
Keyword(s):  
Numerical Model ◽  
Gas Flow ◽  
Reaction Rate ◽  
Heat Storage ◽  
Bulk Material ◽  
Fixed Bed ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Thermochemical Heat Storage ◽  
Speed Up

Calcium oxide/Calcium hydroxide can be utilized as a reaction system for thermochemical heat storage. It features a high storage capacity, is cheap, and does not involve major environmental concerns. Operationally, different fixed-bed reactor concepts can be distinguished; direct reactor are characterized by gas flow through the reactive bulk material, while in indirect reactors, the heat-carrying gas flow is separated from the bulk material. This study puts a focus on the indirectly operated fixed-bed reactor setup. The fluxes of the reaction fluid and the heat-carrying flow are decoupled in order to overcome limitations due to heat conduction in the reactive bulk material. The fixed bed represents a porous medium where Darcy-type flow conditions can be assumed. Here, a numerical model for such a reactor concept is presented, which has been implemented in the software DuMux. An attempt to calibrate and validate it with experimental results from the literature is discussed in detail. This allows for the identification of a deficient insulation of the experimental setup. Accordingly, heat-loss mechanisms are included in the model. However, it can be shown that heat losses alone are not sufficient to explain the experimental results. It is evident that another effect plays a role here. Using Bayesian inference, this effect is identified as the reaction rate decreasing with progressing conversion of reactive material. The calibrated model reveals that more heat is lost over the reactor surface than transported in the heat transfer channel, which causes a considerable speed-up of the discharge reaction. An observed deceleration of the reaction rate at progressed conversion is attributed to the presence of agglomerates of the bulk material in the fixed bed. This retardation is represented phenomenologically by mofifying the reaction kinetics. After the calibration, the model is validated with a second set of experimental results. To speed up the calculations for the calibration, the numerical model is replaced by a surrogate model based on Polynomial Chaos Expansion and Principal Component Analysis.

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