A Model of Asperity Interactions in Elastic-Plastic Contact of Rough Surfaces

2000 ◽  
Vol 123 (4) ◽  
pp. 857-864 ◽  
Author(s):  
Yongwu Zhao ◽  
L. Chang
Keyword(s):  
Plastic Deformation ◽  
Rough Surfaces ◽  
Local Deformation ◽  
Contact Model ◽  
Contact Load ◽  
Elastic Plastic ◽  
Surface Separation ◽  
Local Contact ◽  
Mean Pressure ◽  
The Mean

This paper presents a micro-contact model incorporating asperity interactions in elastic-plastic contact of rough surfaces. The effect of the asperity interactions on the local deformation behavior of a given micro-contact is first modeled based on the Saint-Venant’s Principle and Love’s Formula. The local contact interference is related in closed form to the local contact load, the global mean pressure and material parameters. This micro-contact model equation is then integrated into the elastic-plastic contact model developed in Zhao et al. (2000) to allow the asperity interactions and plastic deformation to be considered simultaneously. The effects of the asperity interactions on the mean surface separation, the real area of contact and the redistribution of the contact load among contacting asperities of different heights are studied. The results show that the asperity interactions can significantly affect the mean surface separation and micro-contact load redistribution. The results also reveal that the effect of asperity interactions can be largely cancelled out by the effect of asperity plastic deformation.

An Asperity Microcontact Model Incorporating the Transition From Elastic Deformation to Fully Plastic Flow

1999 ◽  
Vol 122 (1) ◽  
pp. 86-93 ◽  
Author(s):  
Yongwu Zhao ◽  
David M. Maietta ◽  
L. Chang
Keyword(s):  
Plastic Flow ◽  
Elastic Deformation ◽  
Rough Surfaces ◽  
Plasticity Index ◽  
Contact Load ◽  
Elastic Plastic ◽  
Surface Separation ◽  
Surface Plasticity ◽  
Wide Range ◽  
The Mean

This paper presents an elastic-plastic asperity microcontact model for contact between two nominally flat surfaces. The transition from elastic deformation to fully plastic flow of the contacting asperity is modeled based on contact-mechanics theories in conjunction with the continuity and smoothness of variables across different modes of deformation. The relations of the mean contact pressure and contact area of the asperity to its contact interference in the elastoplastic regime of deformation are respectively modeled by logarithmic and fourth-order polynomial functions. These asperity-scale equations are then used to develop the elastic-plastic contact model between two rough surfaces, allowing the mean surface separation and the real area of contact to be calculated as functions of the contact load and surface plasticity index. Results are presented for a wide range of contact load and plasticity index, showing the importance of accurately modeling the deformation in the elastoplastic transitional regime of the asperity contacts. The results are also compared with those calculated by the GW and CEB models, showing that the present model is more complete in describing the contact of rough surfaces. [S0742-4787(00)01201-7]

A statistical model of elastic-plastic contact between rough surfaces

2019 ◽  
Vol 43 (1) ◽  
pp. 38-46 ◽  
Author(s):  
Guang Zhao ◽  
Sheng-xiang Li ◽  
Zhi-liang Xiong ◽  
Wen-dong Gao ◽  
Qing-kai Han
Keyword(s):  
Plastic Deformation ◽  
Interface Design ◽  
Present Model ◽  
Rough Surfaces ◽  
Contact Stiffness ◽  
Contact Point ◽  
Contact Model ◽  
Elastic Plastic ◽  
Classical Models ◽  
Asperity Deformation

In a mechanical interface, the contact surface topography has an important influence on the contact stiffness. In the contact processes of asperities, elastic-plastic change can lead to discontinuity and lack of smoothness at a critical contact point. The result is a large difference between the elastic-plastic deformation and the actual asperity deformation. Based on Hertz contact theory, the heights of asperities on a rough surface obey a Gaussian distribution. To take into consideration the continuity of elastic-plastic asperity deformation, we divide the elastic-plastic deformation into three stages: pre-elastic-plastic, mid-elastic-plastic, and post-elastic-plastic deformation. This establishes an elastic-plastic contact model of asperity at a continuous critical point. The contact model of a single asperity fits well with the Kogut–Etsion model and the Zhao–Maietta–Chang model, and the variation trend is consistent. At a lower plastic index, the present model coincides with classical models of contact area and contact load. At a higher plastic index, the simulation results of the present model differ from the Greenwood–Williamson model and the Chang–Etsion–Bogy model but are similar to results from the Kogut–Etsion and Zhao–Maietta–Chang models. This study provides a more accurate microscopic contact model for rough surfaces and a theoretical framework for interface design and analysis.

Elastic-Plastic Contact Behavior Considering Asperity Interactions for Surfaces With Various Height Distributions

2005 ◽  
Vol 128 (2) ◽  
pp. 245-251 ◽  
Author(s):  
Yeau-Ren Jeng ◽  
Shin-Rung Peng
Keyword(s):  
Contact Area ◽  
Rough Surfaces ◽  
Local Deformation ◽  
Real Contact Area ◽  
Recent Experimental Data ◽  
The Real ◽  
Surface Separation ◽  
Real Contact ◽  
The Mean ◽  
Non Gaussian

This study investigates the effects of asperity interactions on the mean surface separation and the real contact area for rough surfaces with non-Gaussian height distributions. The effects of the asperity interactions on the local deformation behavior of a given microcontact are modeled using the Saint Venant principle and Love’s formula. The non-Gaussian rough surfaces are described by the Johnson translatory system. The results indicate that asperity interactions can significantly affect the mean separation of surfaces with non-Gaussian height distributions. The findings also reveal that the contact load and the real contact area of surfaces with non-Gaussian height distributions are significantly different from those of surfaces with Gaussian height distributions. This study uncovers that skewed surfaces tend to deform more elastically, which provides underlying physics for the long-time conventional wisdom and recent experimental data [Y. R. Jeng, 1996, Tribol. Trans., 39, 354–361;Y. R. Jeng, Z. W. Lin, and S. H. Shyo, 2004, ASME J. Tribol., 126, 620–625] that running-in surfaces have better wear resistance.

The Characteristics of Elastically Contacting Ideal Rough Surfaces

1996 ◽  
Vol 118 (1) ◽  
pp. 90-97 ◽  
Author(s):  
Leng Yongsheng ◽  
Yang Guiping ◽  
Huang Yan ◽  
Zheng Linqing
Keyword(s):  
Mutual Influence ◽  
Rough Surfaces ◽  
Spatial Distance ◽  
Reference Plane ◽  
Elastic Contact ◽  
Line Position ◽  
Loading Level ◽  
Mean Pressure ◽  
The Mean ◽  
Vertical Height

The analysis of the elastic contact of ideal rough surfaces is presented in this paper. The rough asperities are assumed to be spherical with the same vertical height and spatial distance. The mutual influence of asperities is considered. Numerical results show that for the same load, the contact area is less than the Hertzian prediction, while the pressure distribution is still of a Hertzian type, but is increased to some extent. We find that the asperity interaction is associated with a parameter, called the “loading level,” which combines the surface texture, mechanical properties, and the nominal mean pressure. Of significant importance is the discovery of the variation of the reference plane position with the contact load. In the classical theory of rough contact (Greenwood and Williamson, 1966), the reference plane was in fact assumed to be in the mean line position. We prove that the location of the reference plane is determined by the number of contacting asperities and the loading level, thus making the analysis of the contact of rough surfaces somewhat complex.

The Investigation of Energy Loss in Conformal Contact Mechanics of Carpal-Radial Components in Wrist Arthroplasty

2014 ◽  
Author(s):  
Mohammad Hodaei ◽  
Kambiz Farhang
Keyword(s):  
Surface Roughness ◽  
Energy Loss ◽  
Contact Mechanics ◽  
Contact Force ◽  
Rough Surfaces ◽  
Approximate Equation ◽  
Integral Function ◽  
Contact Model ◽  
Metal Debris ◽  
Surface Separation

The contact mechanics of Wrist prosthetic implant is considered in which the surface roughness of the implant is included. Total wrist replacements are developed to perform wrist function as near normal as possible. The main goal of wrist replacement surgery is to relieve patients from painful arthritis and to maintain function in the wrist and hand. The gradual wearing away of the cartilage covering on bones can lead to the most common form of arthritis, usually osteoarthritis. Wear is a very important issue in wrist implant. Metal debris caused by excessive wear in wrist implant can lead to toxicity and patient discomfort. Since implant wear can be the result of contact between surfaces of Carpal and Radial components, so the investigation of the effect of roughness between wrist components and establishing a model for interaction of surface roughness is very important. There are several different designs of wrist implant. Most of them have two components that are made of metal. A high quality plastic called polyethylene is used as a space between the two components. The purpose of this paper is to investigate the effect of roughness between interaction of these metal and polyethylene in wrist implants. This paper develops a contact model to treat the interaction of Carpal - Radial Components. The contact model describes the interaction of implant rough surfaces including both elastic and plastic deformations. In the model, surfaces are investigated as macroscopically conforming semi-Cylinder containing micron-scale roughness. The derived equations relate contact force on the implant and the minimum mean surface separation of the rough surfaces. Based on the distribution of asperity heights, the force is expressed using statistical integral function of asperity heights over the possible region of interaction of the roughness of the implant surfaces. Closed-form approximate equation relating contact force and minimum separation is used to obtain energy loss per cycle in a load-unload sequence applied to the implant.

An Elliptical Microcontact Model Considering Elastic, Elastoplastic, and Plastic Deformation

2003 ◽  
Vol 125 (2) ◽  
pp. 232-240 ◽  
Author(s):  
Yeau-Ren Jeng ◽  
Pei-Ying Wang
Keyword(s):  
Plastic Deformation ◽  
Contact Pressure ◽  
Contact Area ◽  
Contact Model ◽  
Real Area Of Contact ◽  
Elliptical Contact ◽  
The Mean ◽  
Elliptic Contact ◽  
Circular Contact ◽  
Real Area

This study developed an elastic-plastic microcontact model that considers the elliptical contact of surface asperities. In the elastoplastic regime, the relations of the mean contact pressure and contact area of asperity to its contact interference are modeled considering the continuity and smoothness of variables across different modes of deformation. Results obtained from this model are compared with other existing models such as that calculated by the GW, CEB, Zhao and Horng models. The elliptic contact model and circular contact model can deviate considerably in regard to the separation and real area of contact.

Elastic-Plastic Contact Between Rough Surfaces: Proposal for a Wear or Running-In Model

2005 ◽  
Vol 128 (2) ◽  
pp. 236-244 ◽  
Author(s):  
D. Nélias ◽  
V. Boucly ◽  
M. Brunet
Keyword(s):  
Rough Surfaces ◽  
Companion Paper ◽  
Contact Model ◽  
Surface Shear Stress ◽  
Surface Shear ◽  
Mapping Algorithm ◽  
Elastic Plastic ◽  
Perfectly Plastic ◽  
Hardening Law ◽  
Von Mises

A semi-analytical thermo-elastic-plastic contact model has been recently developed and presented in a companion paper. The main advantage of this approach over the classical finite element method (FEM) is the treatment of transient problems with the use of fine meshing and the possibility of studying the effect of a surface defect on the surface deflection as well as on subsurface stress state. A return-mapping algorithm with an elastic predictor/plastic corrector scheme and a von Mises criterion is now used, which improves the plasticity loop. This improvement in the numerical algorithm increases the computing speed significantly and shows a much better convergence and accuracy. The contact model is validated through a comparison with the FEM results of Kogut and Etsion (2002, J. Appl. Mech., 69, pp. 657–662) which correspond to the axisymmetric contact between an elastic-perfectly plastic sphere and a rigid flat. A model for wear prediction based on the material removal during cyclic loading is then proposed. Results are presented, first, for initially smooth surfaces and, second, for rough surfaces. The effects of surface shear stress and hardening law are underlined.

An Elastic-Plastic Model for the Contact of Rough Surfaces

1987 ◽  
Vol 109 (2) ◽  
pp. 257-263 ◽  
Author(s):  
W. R. Chang ◽  
I. Etsion ◽  
D. B. Bogy
Keyword(s):  
Plastic Deformation ◽  
Control Volume ◽  
Rough Surfaces ◽  
Numerical Results ◽  
Volume Conservation ◽  
Plastic Model ◽  
Elastic Plastic ◽  
Asperity Model

An elastic-plastic asperity model for analyzing the contact of rough surfaces is presented. The model is based on volume conservation of an asperity control volume during plastic deformation. Numerical results obtained from this model are compared with other existing models that are either purely elastic or purely plastic. It is shown that these models are limiting cases of the more general elastic-plastic model presented here. Some of the results obtained deviate appreciably from previous analyses which do not consider asperity volume conservation.

Fractal modeling of elastic-plastic contact between three-dimensional rough surfaces

2018 ◽  
Vol 70 (2) ◽  
pp. 290-300 ◽  
Author(s):  
Rufei Yu ◽  
Wei Chen
Keyword(s):  
Rough Surfaces ◽  
Fractal Theory ◽  
Three Dimensional ◽  
Geometrical Model ◽  
Contact Model ◽  
Radial Clearance ◽  
Content Type ◽  
Elastic Plastic ◽  
Fractal Roughness ◽  
Conformal Contact

Purpose This paper aims to propose a semi-analytical model to investigate the elastic-plastic contact between fractal rough surfaces. Parametric studies have been performed to analyze the dependencies between the contact properties and the scale-independent fractal parameters. Design/methodology/approach A modified two-variable Weierstrass-Mandelbrot function has been used to build the geometrical model of rough surfaces. The computation program was developed using software MATLAB R2015a. The results have been qualitatively validated by the existing theoretical and experimental results in the literature. Findings In most cases, a nonlinear relation between the load and the displacement of the rigid plane is found. Only under the condition of larger loads, an approximate linear relation can be seen for great D and small G values. (D: fractal dimension and G: fractal roughness). Originality/value The contact model of the cylindrical joints (conformal contact) with radial clearance is constructed by using the fractal theory and the Kogut-Etsion elastic-plastic contact model, which includes purely elastic, elastic-plastic and fully plastic contacts. The present method can generate a more reliable calculation result as compared with the Hertz contact model and a higher calculation efficiency as compared with the finite element method for the conformal contact problem.

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