Thermal Elasto-Plastic Contact Model of Rough Surfaces

2005 ◽  
Author(s):  
Geng Liu ◽  
Tianxiang Liu ◽  
Qin Xie ◽  
Fanghui Shi
Keyword(s):  
Thermal Effects ◽  
Rough Surfaces ◽  
Frictional Heating ◽  
Contact Model ◽  
Stress Fields ◽  
Real Contact Area ◽  
Plastic Behavior ◽  
Contact Conditions ◽  
Real Contact ◽  
Frictional Coefficients

A thermal elasto-plastic contact model is developed in this paper to investigate the influences of steady-state frictional heating on the contact performance of surface asperities and subsurface stress fields. This model takes into account the asperity distortion caused by temperature variation in a tribological process, micro plastic flow of surface asperities, and the coupled thermo-elasto-plastic behavior of materials, with and without considering the strain-hardening property of the materials. The model is verified through the contact analysis between a rigid, isolated cylinder and a plane. Furthermore, the thermal effects on the contact pressure, real contact area, and average gap of rough surfaces in contact with different frictional coefficients and heat inputs under the thermal elasto-plastic contact conditions are studied.

Thermal Effects on Elasto-Plastic Contacts between Rough Surfaces

2006 ◽  
Vol 532-533 ◽  
pp. 801-804
Author(s):  
Geng Liu ◽  
Tian Xiang Liu ◽  
Qin Xie
Keyword(s):  
Steady State ◽  
Thermal Effects ◽  
Rough Surfaces ◽  
Frictional Heating ◽  
Stress Fields ◽  
Frictional Heat ◽  
Plastic Behavior ◽  
Contact Conditions ◽  
Real Area Of Contact ◽  
Real Area

The effects of the steady-state frictional heating on the contact performance of surface asperities and subsurface stress fields between rough surfaces are investigated in this paper. The asperity distortion caused by the temperature variation in a tribological process, micro plastic flow of surface asperities, and the coupled thermo-elasto-plastic behavior of the materials, with and without considering the strain-hardening property of the materials are studied. In addition, the contact pressure, real area of contact, and average gap of real rough surface with different frictional heat inputs under the thermal elasto-plastic contact conditions are analyzed and discussed.

On a model for the prediction of asperity interactions of the coated friction pair

2019 ◽  
Vol 72 (3) ◽  
pp. 449-454 ◽  
Author(s):  
Chunxing Gu ◽  
Shuwen Wang
Keyword(s):  
Optimum Design ◽  
Numerical Experiments ◽  
Rough Surfaces ◽  
Contact Model ◽  
Real Contact Area ◽  
Plastic Behavior ◽  
Asperity Contact ◽  
Content Type ◽  
Contact Behavior ◽  
Elastic Plastic

Purpose Surface coatings have been introduced on the contact surfaces to protect the mechanical parts for a long time. However, in terms of the optimum design of coatings, some key coating parameters are still selected by trial and error. The optimum design of coatings can be conducted by numerical experiments. This paper aims to predict the contact behavior of the coated rough surfaces accurately. One improved asperity contact model for the coated rough surfaces considering the misalignment of asperities would be developed. Design/methodology/approach Incorporating the coated asperity contact model into the improved Greenwood Tripp-based statistical approach, the proposed model can predict the elastic-plastic behaviors of the interacting coated asperities. Findings According to numerical experiments, compared with the coated asperity contact model in which an equivalent rough surface against a plane is assumed, the improved asperity contact model for the coated contacts can account for the effect of permitting misalignment of two rough surfaces. The contacts having the thicker, stiffer and harder coatings result in higher asperity contact pressure and smaller real contact area fraction under the given Stribeck oil film ratio. Originality/value In this paper, one statistical coated asperity contact model for two rough surfaces was developed. The developed model can consider the elastic-plastic behavior of interacting coated asperities. The effects of the coating thickness and its mechanical properties on the contact behavior of the rough surfaces with coatings can be evaluated based on the developed model.

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.

Deterministic Contact Model of a Rough Surface Against a Flat-Layered Surface

2004 ◽  
Author(s):  
H. R. Pasaribu ◽  
D. J. Schipper
Keyword(s):  
Mechanical Properties ◽  
Rough Surface ◽  
Contact Area ◽  
Indentation Depth ◽  
Normal Load ◽  
Contact Model ◽  
Real Contact Area ◽  
Single Asperity ◽  
Real Contact ◽  
Effective Mechanical Properties

The effective mechanical properties of a layered surface vary as a function of indentation depth and the values of these properties range between the value of the layer itself and of the substrate. In this paper, a layered surface is modelled like a solid that has effective mechanical properties as a function of indentation depth by assuming that the layer is perfectly bounded to the substrate. The normal load as a function of indentation depth of sphere pressed against a flat layered surface is calculated using this model and is in agreement with the experimental results published by El-Sherbiney (1975), El-Shafei et al. (1983), Tang & Arnell (1999) and Michler & Blank (2001). A deterministic contact model of a rough surface against a flat layered surface is developed by representing a rough surface as an array of spherically shaped asperities with different radii and heights (not necessarily Gaussian distributed). Once the data of radius and height of every single asperity is obtained, one can calculate the number of asperities in contact, the real contact area and the load carried by the asperities as a function of the separation.

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.

A Fractal Theory of the Interfacial Temperature Distribution in the Slow Sliding Regime: Part II—Multiple Domains, Elastoplastic Contacts and Applications

1994 ◽  
Vol 116 (4) ◽  
pp. 824-832 ◽  
Author(s):  
S. Wang ◽  
K. Komvopoulos
Keyword(s):  
Temperature Distribution ◽  
Contact Area ◽  
Temperature Rise ◽  
Frictional Heating ◽  
Fractal Theory ◽  
Cumulative Distribution ◽  
Maximum Temperature ◽  
Real Contact Area ◽  
Fractal Structures ◽  
Real Contact

The limitation of the fractal theory as applied to real surfaces is interpreted, and engineering surfaces are considered as a superimposition of fractal structures on macroscopic regular shapes by introducing the concepts of fractal-regular surfaces and multiple fractal domains. The effects of frictional heating at neighboring microcontacts are analyzed, and a simple solution of the temperature distribution is obtained for contact regions that are appreciably larger than a fractal domain. It is shown that the temperature rise at an elastoplastic microcontact does not differ significantly from that at an elastic microcontact of a similar geometry under the same load. The fractional real contact area subjected to temperature rises greater than any given value is represented by a complementary cumulative distribution function. The analysis yields that the average value and standard deviation of the temperature rise at the real contact area are 0.4 and 0.24 times the maximum temperature rise, respectively. The implications of the theory in boundary lubrication are demonstrated in light of results for ceramic materials.

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.

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