Plastic Deterministic Contact of Rough Surfaces

2007 ◽  
Vol 129 (4) ◽  
pp. 957-962 ◽  
Author(s):  
J. Jamari ◽  
M. B. de Rooij ◽  
D. J. Schipper
Keyword(s):  
Experimental Investigation ◽  
Plastic Deformation ◽  
Theoretical Model ◽  
Surface Topography ◽  
Rough Surface ◽  
Contact Area ◽  
Rough Surfaces ◽  
Bulk Deformation ◽  
Elliptical Contact ◽  
Single Contact

In this paper, a theoretical and experimental investigation is presented to study the contact behavior of the plastic contact of deterministic rough surfaces. Analyses exclude bulk deformation of the rough surface and concentrate to the contact on asperity level. Surface asperities are modeled by an array of elliptic paraboloids where the unit event of a single contact is analyzed using an elastic-plastic elliptical contact model. A new method to determine the surface topography change due to plastic deformation is presented. Results show that the theoretical model developed predicts the contact area and the deformed geometry of the rough surface very well.

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.

Application of Contourlet in Research of Rough Surface Topography

2012 ◽  
Vol 542-543 ◽  
pp. 115-118
Author(s):  
Chao Zhou ◽  
Cheng Hui Gao
Keyword(s):  
Surface Topography ◽  
Rough Surface ◽  
Surface Analysis ◽  
Signal Analysis ◽  
Elementary Theory ◽  
Rough Surfaces ◽  
Good Method ◽  
Two Dimensional ◽  
Multi Scale

Since the tribology properties of rough surfaces are closely related to its topography, one of the most important ingredients in tribology research is to find an appropriate tool to analyze and characterize rough surfaces. The elementary theory of contourlet which is a good method for multi-scale and multi-direction signal analysis was introduced and an application of contourlet in rough surface analysis was demonstrated. It was found that contourlet is more sensitive to curved features than general two dimensional wavelets; it is possible to become a new powerful tool for rough surface analysis and characterization.

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 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.

Theoretical and Experimental Investigation of Plastic Hysteresis in Spherical Contact Under Combined Normal and Tangential Loading

2008 ◽  
Author(s):  
Yuri Kligerman ◽  
Andrey Ovcharenko ◽  
Izhak Etsion ◽  
Gregory Halperin
Keyword(s):  
Experimental Investigation ◽  
Theoretical Model ◽  
Stress State ◽  
Contact Area ◽  
Kinematic Hardening ◽  
Contact Condition ◽  
Tangential Displacement ◽  
Elastic Plastic ◽  
Plastic Sphere ◽  
Good Agreement

The behavior of an elastic-plastic contact between a deformable sphere and a rigid flat under combined constant normal and reciprocating tangential loading is investigated theoretically and experimentally. The theoretical model is based on the assumptions of full stick contact condition and elastic–linear kinematic hardening of the sphere material. Hysteretic change of friction force versus tangential displacement during reciprocating tangential loading is investigated along with the study of the change of the contact area and stress state in the elastic-plastic sphere. Good agreement between theoretical and experimental results is obtained.

Molecular Dynamics Simulation of Single Asperity Contact

2004 ◽  
Author(s):  
Pil-Ryung Cha ◽  
Jun Song ◽  
T. Kyle Vanderlick ◽  
David J. Srolovitz
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Contact Resistance ◽  
Contact Area ◽  
Rough Surfaces ◽  
Asperity Contact ◽  
Single Asperity ◽  
Wide Range ◽  
Loading And Unloading ◽  
Elastic And Plastic Deformation

Many state-of-art microelectronic, photonic and MEMS devices are based upon or created using small-scale contacts. These include, for example, high frequency, microscale electromechanical switches and nanopatterning of organic optoelectronic materials by contact adhesion, cold welding, and lift-off. The initial stages of contact occur between asperities of micro- and/or nano-scopic dimensions. As a consequence, understanding the processes that occur at the atomic level when two rough surfaces are bought into contact is fundamentally important for a wide range of problems including adhesion, contact formation, contact resistance, materials hardness, friction, wear, and fracture. The centrality of single asperities in the fundamental micromechanical response of contact between two rough surfaces has long been recognized. A wide range of experiments has shown that the conductance of small contacts changes abruptly as a function of contact size. In some cases, the conductance through individual asperities increases in a stepwise manner as the two surfaces are pressed into contact. These jumps conductance appear to be correlated with jumps in the force. The observed force-displacement relation appears to be poorly described by JKR theory during loading, while JKR provides a reasonable description of the behavior in unloading. In this presentation (see Acta Materialia 52, 3983 (2004) for more details), we report the results of molecular dynamics simulations of single asperity contact during multiple cycles of loading and unloading at room temperature. We focus on the mechanisms by which contact deformation occurs and the relationship between contact conductance (and contact area) and the deformation. These simulations account for adhesion, elastic deformation, dislocation generation and migration, the formation of other types of defects and morphology evolution. In order to study the elastic and plastic deformation of the asperities on a rough surface, we set up a model system, as shown in Fig. 1. For simplificity, we consider a single deformable asperity on a deformable substrate that interacts with a flat, rigid plate. We calculate the conductance of the contact during loading and unloading through the modified Sharvin model [12]. To our knowledge, this study represents the first dynamic, atomistic simulation of the elastic and plastic deformation behavior of a single asperity and the corresponding evolution of the contact area and contact conductance. The present simulation results reproduce a large body of existing nano-contact experimental results, including the stepwise variation of contact area and conductance with displacement and the hysteresis in the contact radius and contact resistance versus force curves.

Method for Calculating Plastic Deformation of High Resolution and Large Contact Area

2021 ◽  
Vol 144 (1) ◽  
Author(s):  
S. Sklenak ◽  
D. Mevissen ◽  
J. Brimmers ◽  
C. Brecher
Keyword(s):  
Plastic Deformation ◽  
High Resolution ◽  
Pressure Distribution ◽  
Rough Surface ◽  
Tribological Properties ◽  
Contact Area ◽  
Three Dimensional ◽  
Rolling Contact ◽  
Contact Algorithm ◽  
Large Contact Area

Abstract In a rolling contact, the tribological properties in terms of friction, wear, and fatigue are significantly influenced by the surface roughness. Due to solid contact of the surfaces in the contact area, the roughness and thus also the tribological properties change during the service life of the contact. The initial load leads to major changes of the tribological properties figured out by Brecher et al. (2019, “Influence of the Metalworking Fluid on the Micropitting Wear of Gears,” Wear, 61(434–435), p. 202996). Prediction of the initial changes in topography in the contact area is necessary for specific optimization of rolling contacts. Especially for dry rolling–sliding contact, the roughness of the surfaces is crucial for the lifetime, which is part of the investigations within the DFG priority program 2074 (357505886). In this work, an elastic-plastic contact algorithm for calculating plastic deformation for dry contact of rough surfaces with large contact area and high resolution is presented. Due to the nonlinearity behavior associated with plastic deformation, the plastic contact algorithm is based on an iterative approach. An optimized meshing strategy is implemented to calculate the elastic pressure distribution on the surface. Corresponding to the two-dimensional pressure distribution, the three-dimensional stress distribution allows the consideration of residual stresses and interactions of the microscopic peaks of the rough surface. Furthermore, the three-dimensional plastic strain distribution allows the application of an analytical approach to represent the plastic deformation of the surface. Finally, the solution of a plastic contact calculation with an exemplary topography measured on a real rough surface is presented.

A Contact Mechanics Model for Rough Surfaces Based on a New Fractal Characterization Method

2018 ◽  
Vol 10 (06) ◽  
pp. 1850069 ◽  
Author(s):  
Jianjun Sun ◽  
Zhengbo Ji ◽  
Yuyan Zhang ◽  
Qiuping Yu ◽  
Chenbo Ma
Keyword(s):  
Contact Mechanics ◽  
Rough Surface ◽  
Contact Pressure ◽  
Contact Area ◽  
Rough Surfaces ◽  
Contact Stiffness ◽  
Measurement Scale ◽  
Real Contact Area ◽  
Sample Length ◽  
Normal Contact

There are mainly two kinds of contact mechanics models for rough surfaces. One is based on the statistical characteristic parameters and depends on the measurement scale of rough surface topography. The other is based on the fractal parameters, which is independent of the measurement scale. However, most of the contact models for rough surfaces based on fractal theory use the size that is corresponding to the contact area of an asperity or the sample length as the base diameter of an asperity to describe the initial profile of asperities. As a result, the obtained deformation mechanism of asperities is not correct. To solve this problem, a new fractal characterization method for rough surfaces based on the fractal dimension [Formula: see text], fractal roughness [Formula: see text] and the highest asperity height is proposed, and then a fractal contact model independent of the measurement scale is established. The contact mechanism of asperities and variation trends of the real contact area and contact stiffness are discussed. When the contact pressure of the rough surface is less than its yield strength, its normal contact stiffness can be expressed as the first derivative of the contact pressure versus the normal compression, regardless of the deformation forms of asperities.

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