scholarly journals A semi-analytical approach to the elastic loading behaviour of rough surfaces

Friction ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 970-981
Author(s):  
Xiaogang Zhang ◽  
Yali Zhang ◽  
Zhongmin Jin
Keyword(s):  
Contact Area ◽  
Rough Surfaces ◽  
Real Contact Area ◽  
Exponential Relationship ◽  
Load Range ◽  
Contact Behaviour ◽  
Elastic Loading ◽  
Moderate Load ◽  
Convergence Problems ◽  
Linear Decay

AbstractThe elastic loading behaviour of rough surfaces is derived based on the physical understanding of the contact phenomena, where the pressure distribution is analytically obtained without any negative values or convergence problems, thus the evolution of the contact behaviour is obtained in a semi-analytical manner. Numerical results obtained by the proposed approach facilitate the understanding of the contact behaviour in the following aspects: 1) the ratio of contact area to load decreases with an increase in real contact area; 2) normal approach-load relationship is approximated by an exponential decay under relatively small loads and a linear decay under relatively large loads; and 3) average gap shows an exponential relationship with load only in moderate load range.

scholarly journals Measurement of Real Contact Area for Rough Metal Surfaces and the Distinction of Contribution From Elasticity and Plasticity

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
Lei-Tao Li ◽  
Xuan-Ming Liang ◽  
Yu-Zhe Xing ◽  
Duo Yan ◽  
Gang-Feng Wang
Keyword(s):  
Contact Area ◽  
Rough Surfaces ◽  
Normal Load ◽  
Real Contact Area ◽  
The Real ◽  
Physical Mechanisms ◽  
Frustrated Total Internal Reflection ◽  
Real Contact ◽  
New Apparatus ◽  
Elastic And Plastic Deformation

Abstract The measurement of the real contact area between rough surfaces is one of the most challenging problems in contact mechanics and is of importance to understand some physical mechanisms in tribology. Based on the frustrated total internal reflection, a new apparatus is designed to measure the real contact area. For metallic samples with various surface topographies, the relation between normal load and the real contact area is measured. The unloading process is first considered to distinguish the contribution of elasticity and plasticity in contact with rough surfaces. It is found that both elasticity and plasticity are involved throughout the continuous loading process, different from some present understanding and assumptions that they play at different loading stages. A quantitative parameter is proposed to indicate the contribution of plasticity. The present work not only provides an experimental method to measure the real contact area but figures out how elastic and plastic deformation works in contact with rough surfaces.

Influence of the in-plan distribution of asperities on the normal contact of periodically rough surfaces

2016 ◽  
Vol 230 (9) ◽  
pp. 1382-1391
Author(s):  
K Houanoh ◽  
H-P Yin ◽  
J Cesbron ◽  
Q-C He
Keyword(s):  
Numerical Simulations ◽  
Half Space ◽  
Contact Area ◽  
Rough Surfaces ◽  
Elastic Half Space ◽  
Real Contact Area ◽  
Normal Contact ◽  
Real Contact ◽  
Full Contact ◽  
Rigid Surfaces

The present work aims to analyze the influence of the in-plan distribution of asperities on the contact between periodically rough surfaces. Square pattern and hexagonal pattern rigid surfaces are considered. Their contact with an elastic half-space is analyzed by numerical simulations. Three surfaces are generated with identical asperities periodically distributed in a plan according to different patterns. It follows from numerical results that when the load and the real contact area are small, the asperities act almost independently. However, the interaction between close asperities increases with the load becomes intensified and has a significant effect on the contact area when the situation is close to full contact.

Strongly Anisotropic Rough Surfaces

1979 ◽  
Vol 101 (1) ◽  
pp. 15-20 ◽  
Author(s):  
A. W. Bush ◽  
R. D. Gibson ◽  
G. P. Keogh
Keyword(s):  
Random Process ◽  
Rough Surface ◽  
Contact Area ◽  
Process Model ◽  
Rough Surfaces ◽  
Plasticity Index ◽  
Real Contact Area ◽  
Elastic Contact ◽  
Elastic Plastic ◽  
Real Contact

The statistics of a strongly anisotropic rough surface are briefly described. The elastic contact of rough surfaces is treated by approximating the summits of a random process model by parabolic ellipsoids and applying the Hertzian solution for their deformation. Load and real contact area are derived as functions of the separation and for all separations the load is found to be approximately proportional to the contact area. The limits of elastic/plastic contact are discussed in terms of the plasticity index.

Prediction of Contact Area and Frictional Behaviour of Rubber on Rigid Rough Surfaces

2014 ◽  
Author(s):  
Hagen Lind ◽  
Matthias Wangenheim
Keyword(s):  
Contact Area ◽  
Surface Texture ◽  
Rough Surfaces ◽  
Scale Model ◽  
Real Contact Area ◽  
Contact Friction ◽  
Sliding Velocity ◽  
Normal Contact ◽  
Multi Scale ◽  
Frictional Behaviour

In the tire-road contact friction depends on several influencing variables (e.g. surface texture, real contact area, sliding velocity, normal contact pressure, temperature, tread block geometry, compound and on the existence of a lubrication film). A multi-scale model for prediction of contact area and frictional behaviour of rubber on rigid rough surfaces at different length scales is presented. Within this publication the multi-scale approach is checked regarding convergence. By means of the model influencing parameters like sliding velocity, compound and surface texture on friction and contact area will be investigated.

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.

Pressures Distributions and Depth Stresses Developed in Concentrated Contacts Between Elements With Non-Gaussian Rough Surfaces

2012 ◽  
Author(s):  
Ana C. Urzică ◽  
Mihaela Rodica D. Bălan ◽  
Spiridon S. Creţu
Keyword(s):  
Pressure Distribution ◽  
Autocorrelation Function ◽  
Contact Area ◽  
Rough Surfaces ◽  
Spectral Characteristics ◽  
Equivalent Stress ◽  
Real Contact Area ◽  
Main Step ◽  
Spatial Characteristics ◽  
Non Gaussian

The main step in a contact analysis between rough surfaces is the evaluation of the pressure distribution developed on the real contact area. The normal pressure distribution can be used further to predict subsurface stress, interfacial friction and surface wear. Only few real rough surfaces are Gaussian, most of that produced by manufacturing processes are non-Gaussian having an arbitrarily orientation. The definition of the roughness will include, in addition to the spatial characteristics, information about spectral characteristics of the surface, described with the use of autocorrelation function ACF. Conjugate Gradient Method in conjunction with Discrete Convolution Fast Fourier Transform was refined and applied to solve the constrained system of equations that governs the pressure distribution between rough surfaces subjected to contact loading in elastic dry conditions. The paper reveals the role played by the spatial characteristics (standard deviation σ, skewness Sk, and kurtosis K) as well as by autocorrelation function on both the non-Hertzian pressure distribution on contact area and depth distribution of von Mises equivalent stress.

scholarly journals Mechanics Analysis of Rough Surface Based on Shoulder-Shoulder Contact

2021 ◽  
Vol 11 (17) ◽  
pp. 8048
Author(s):  
Qiuping Yu ◽  
Jianjun Sun ◽  
Zhengbo Ji
Keyword(s):  
Rough Surface ◽  
Contact Area ◽  
Rough Surfaces ◽  
Geometric Model ◽  
Mechanical Analysis ◽  
Real Contact Area ◽  
Mechanics Model ◽  
Porosity Reduction ◽  
Fractal Roughness ◽  
Fractal Characteristics

Proper methods and models for mechanical analysis of rough surface can improve the theory of surface contact. When the topography parameters of two rough surfaces are similar, the contact should be considered shoulder-shoulder rather than top-top. Based on shoulder-shoulder contact and fractal characteristics, the geometric model for asperity and contact mechanics model for rough surfaces are established, and the deformation of asperity, the real contact area and contact load of sealing surface are discussed. The effects of contact pressure p and topography parameters (fractal dimension D and fractal roughness G) on the variation of porosity and contact area ratio Ar/A0 are achieved. Results show that with the increase of p, larger D and smaller G corresponds to larger initial porosity but faster and larger decrease of porosity; with the increment of D, porosity increases first and then decreases, and smaller G corresponds to larger porosity reduction; as G becomes bigger, porosity increases, and larger D corresponds to larger porosity difference and change. With the addition of p, Ar/A0 increases, and the variation of Ar/A0 is closer to linearity and less at smaller D and larger G; with the increase of D, Ar/A0 increases gradually, and the growth rate is bigger at smaller G and bigger p; as G becomes bigger, Ar/A0 declines, and it declines more gently at smaller D and p. The influence of D on Ar/A0 is greater than that of G. The results can provide the theoretical basis for the design of sealing surfaces and the research of sealing or lubrication technologies of rough surfaces.

An incremental equivalent circular contact model for rough surfaces

2021 ◽  
pp. 1-16
Author(s):  
Gangfeng Wang ◽  
Xuan-Ming Liang ◽  
Yan Duo
Keyword(s):  
Contact Area ◽  
Rough Surfaces ◽  
Normal Load ◽  
Real Contact Area ◽  
Contact Radius ◽  
Surface Separation ◽  
Real Contact ◽  
Proposed Model ◽  
Geometrical Information ◽  
Circular Contact

Abstract The accurate calculation of real contact area between rough surfaces is a key issue in tribology. In this paper, based on the geometrical information of total contact area and the number of contact patches with respect to surface separation, a new method is proposed to determine the relation between real contact area and normal load. The contact of rough surfaces is treated as an accumulation of equivalent circular contacts with varying average contact radius. For a realistic range of separation, the proposed model predicts a linear relation between real contact area and load, and coincides well with direct finite element calculations. Moreover, this model is general and not confined to isotropic Gaussian surfaces.

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