The Experts below are selected from a list of 34161 Experts worldwide ranked by ideXlab platform
Izhak Etsion - One of the best experts on this subject based on the ideXlab platform.
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Experimental Study of Adhesive Static Friction in a Spherical Elastic-Plastic Contact
Journal of Tribology-transactions of The Asme, 2008Co-Authors: Andrey Ovcharenko, Gregory Halperin, Izhak EtsionAbstract:The elastic-Plastic Contact between a deformable sphere and a rigid flat during presliding is studied experimentally. Measurements of friction force and Contact area are done in real time along with an accurate identification of the instant of sliding inception. The static friction force and relative tangential displacement are investigated over a wide range of normal preloads for several sphere materials and diameters. Different behavior of the static friction is observed in the elastic and in the elastic-Plastic regimes of sphere deformation. It is found that at low normal loads, the static friction coefficient depends on the normal load in breach of the classical laws of friction. The presliding displacement is found to be less than 5% of the Contact diameter, and the interface mean shear stress at sliding inception is found to be slightly below the shear strength of the sphere material. Good correlation is found between the present experimental results and a recent theoretical model in the elastic-Plastic regime of deformation.
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Experimental Study of Static Friction in a Spherical Elastic-Plastic Contact
Volume 3: Design; Tribology; Education, 2008Co-Authors: Andrey Ovcharenko, Gregory Halperin, Izhak EtsionAbstract:The elastic-Plastic Contact between a deformable sphere and a rigid flat during pre-sliding is studied experimentally. Measurements of friction force and Contact area are done in real time along with an accurate identification of the instant of sliding inception. The static friction force and relative tangential displacement are investigated over a wide range of normal preloads for several sphere materials and diameters. It is found that at low normal loads the static friction coefficient depends on the normal load in breach of the classical laws of friction. The pre-sliding displacement is found to be less than 5 percent of the Contact diameter, and the interface mean shear stress at sliding inception is found to be slightly below the shear strength of the sphere material. Good correlation is found between the present experimental results and a recent theoretical model in the elastic-Plastic regime of deformation.Copyright © 2007 by ASME
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Pre-Sliding of a Spherical Elastic-Plastic Contact
STLE ASME 2008 International Joint Tribology Conference, 2008Co-Authors: Andrey Ovcharenko, Gregory Halperin, Izhak EtsionAbstract:The elastic-Plastic Contact between a deformable sphere and a rigid flat during pre-sliding is studied experimentally. Measurements of friction force and Contact area are done in real time along with an accurate identification of the instant of sliding inception. The static friction force and relative tangential displacement are investigated over a wide range of normal preloads for several sphere materials and diameters. It is found that at low normal loads the static friction coefficient depends on the normal load in breach of the classical laws of friction. The pre-sliding displacement is found to be less than 5 percent of the Contact diameter, and the interface mean shear stress at sliding inception is found to be slightly below the shear strength of the sphere material. Good correlation is found between the present experimental results and a recent theoretical model in the elastic-Plastic regime of deformation.Copyright © 2008 by ASME
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Unloading an elastic-Plastic Contact of rough surfaces
Journal of the Mechanics and Physics of Solids, 2006Co-Authors: Y. Kadin, Yuri Kligerman, Izhak EtsionAbstract:A statistical model for the unloading of elastic–Plastic Contact of rough surfaces is presented for a single load–unload cycle. The hystereses of load-separation and load real Contact area behavior are analyzed for a wide range of surface roughness and loading conditions. The residual topography of the unloaded rough surfaces is also analyzed and the new distribution functions of asperity heights and summit radii of curvature along with a corresponding GW residual Plasticity index are presented. A new modified Plasticity index (MPI) is suggested which considers the energy dissipation due to unrecovered Plastic deformations. This MPI varies from zero for purely elastic Contacts to unity for purely Plastic Contacts and hence, can better define the level of Plasticity of Contacting rough surfaces compared to the original GW Plasticity index. r 2006 Elsevier Ltd. All rights reserved.
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experimental investigation of the elastic Plastic Contact area and static friction of a sphere on flat
Journal of Tribology-transactions of The Asme, 2005Co-Authors: Izhak Etsion, Gregory Halperin, O Levinson, Michael VarenbergAbstract:An experimental investigation is presented to evaluate recently published models for the Contact and sliding inception of a deformable sphere loaded against a smooth rigid flat. The effects of the normal load on the Contact area, junction growth, and the static friction force in the elastic-Plastic Contact regime are presented. Very good correlation is found between the predicted and measured Contact area. A dramatic decrease of the static friction coefficient with increasing normal loading is observed, similar to the trend predicted by the model. The quantitative agreement is, however, less satisfying. Some possible reasons for the poor agreement are pointed out.
Ziqiang Zhao - One of the best experts on this subject based on the ideXlab platform.
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The effect of hardness distribution by carburizing on the elastic-Plastic Contact performance
Tribology International, 2016Co-Authors: Shengguang Zhang, Haibo Zhang, Wenzhong Wang, Ziqiang ZhaoAbstract:Abstract This paper aims to investigate the effect of the hardness distribution by carburizing on the Contact behaviors. A developed elastic–Plastic Contact model based on a semi-analytical method is used. The effect of hardness on elastic–Plastic Contact behaviors is considered by means of the linear hardness-yielding strength relationship. Different hardness distributions are considered to simulate the possible results obtained in heat treatment. The results show that the hardness distribution and carburizing time/case depth have different influence on the Plastic strain under different loads and roughness, while its influence on the maximum Contact pressure and Contact area ratio is very limited.
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the effect of surface roughness characteristics on the elastic Plastic Contact performance
Tribology International, 2014Co-Authors: Shengguang Zhang, Wenzhong Wang, Ziqiang ZhaoAbstract:Abstract Rough surface elastic–Plastic Contact performance is investigated in this paper. First, a computer program is developed to generate rough surfaces with given parameters; Then, the elastic–Plastic Contact model is developed based on minimization of complementary energy and semi-analytical method; finally, Contact analysis for rough surfaces are conducted. The results show that kurtosis and skewness have significant effects on the Contact performance under light-medium load; for heavy load condition and small skewness, the Contact characteristic parameters change slightly along with kurtosis. Comparing with elastic Contact, the low Contact pressure and large Contact area are predicted in elastic–Plastic Contacts.
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The effect of surface roughness characteristics on the elastic–Plastic Contact performance
Tribology International, 2014Co-Authors: Shengguang Zhang, Wenzhong Wang, Ziqiang ZhaoAbstract:Abstract Rough surface elastic–Plastic Contact performance is investigated in this paper. First, a computer program is developed to generate rough surfaces with given parameters; Then, the elastic–Plastic Contact model is developed based on minimization of complementary energy and semi-analytical method; finally, Contact analysis for rough surfaces are conducted. The results show that kurtosis and skewness have significant effects on the Contact performance under light-medium load; for heavy load condition and small skewness, the Contact characteristic parameters change slightly along with kurtosis. Comparing with elastic Contact, the low Contact pressure and large Contact area are predicted in elastic–Plastic Contacts.
Shengguang Zhang - One of the best experts on this subject based on the ideXlab platform.
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The effect of hardness distribution by carburizing on the elastic-Plastic Contact performance
Tribology International, 2016Co-Authors: Shengguang Zhang, Haibo Zhang, Wenzhong Wang, Ziqiang ZhaoAbstract:Abstract This paper aims to investigate the effect of the hardness distribution by carburizing on the Contact behaviors. A developed elastic–Plastic Contact model based on a semi-analytical method is used. The effect of hardness on elastic–Plastic Contact behaviors is considered by means of the linear hardness-yielding strength relationship. Different hardness distributions are considered to simulate the possible results obtained in heat treatment. The results show that the hardness distribution and carburizing time/case depth have different influence on the Plastic strain under different loads and roughness, while its influence on the maximum Contact pressure and Contact area ratio is very limited.
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the effect of surface roughness characteristics on the elastic Plastic Contact performance
Tribology International, 2014Co-Authors: Shengguang Zhang, Wenzhong Wang, Ziqiang ZhaoAbstract:Abstract Rough surface elastic–Plastic Contact performance is investigated in this paper. First, a computer program is developed to generate rough surfaces with given parameters; Then, the elastic–Plastic Contact model is developed based on minimization of complementary energy and semi-analytical method; finally, Contact analysis for rough surfaces are conducted. The results show that kurtosis and skewness have significant effects on the Contact performance under light-medium load; for heavy load condition and small skewness, the Contact characteristic parameters change slightly along with kurtosis. Comparing with elastic Contact, the low Contact pressure and large Contact area are predicted in elastic–Plastic Contacts.
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The effect of surface roughness characteristics on the elastic–Plastic Contact performance
Tribology International, 2014Co-Authors: Shengguang Zhang, Wenzhong Wang, Ziqiang ZhaoAbstract:Abstract Rough surface elastic–Plastic Contact performance is investigated in this paper. First, a computer program is developed to generate rough surfaces with given parameters; Then, the elastic–Plastic Contact model is developed based on minimization of complementary energy and semi-analytical method; finally, Contact analysis for rough surfaces are conducted. The results show that kurtosis and skewness have significant effects on the Contact performance under light-medium load; for heavy load condition and small skewness, the Contact characteristic parameters change slightly along with kurtosis. Comparing with elastic Contact, the low Contact pressure and large Contact area are predicted in elastic–Plastic Contacts.
Q. Jane Wang - One of the best experts on this subject based on the ideXlab platform.
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A Multilevel Model for Elastic-Plastic Contact Between a Sphere and a Flat Rough Surface
Journal of Tribology, 2009Co-Authors: F. Steven Wang, Wei Chen, Leon M Keer, Joseph M. Block, Ashlie Martini, Kun Zhou, Q. Jane WangAbstract:Elastic-Plastic Contact of a smooth sphere and a half-space with a real machined surface is simulated using an integration-based multilevel Contact model. The total surface deflection is composed of bulk and asperity deformations. They are calculated at the global and the asperity level, respectively, which are connected through the asperity-supporting load. With this new model, the accurate Contact area and Contact pressure under a given load are quickly predicted using a relatively coarse grid system. The calculated load-area curve shows good agreement with the experimental data. Finally, the effects of the surface topography, including roughness and the asperity radius, upon the real Contact area are analyzed.
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Elasto-Plastic Contact behaviors of nominally flat surfaces: Modeling and parametric study
ASME STLE 2007 International Joint Tribology Conference Parts A and B, 2007Co-Authors: Wei Chen, Yuchuan Liu, Jiao Cao, Cedric Xia, Raj Talwar, Rick Lederich, Q. Jane WangAbstract:Interactions of nominally flat surfaces can be modeled based on the periodic similarity of surface topography and a numerical three-dimensional elasto-Plastic Contact model with the assistance of the continuous convolution and Fourier transform (CC-FT) algorithm. The rough surfaces were generated by a digital filtration technology with a wide range of topographical parameters. A group of Contact simulations were conducted to investigate the effects of surface geometrical characteristics (including RMS roughness, correlation length ratio, skewness and kurtosis), material properties, and load on the elasto-Plastic Contact performance of materials.Copyright © 2007 by ASME and The Boeing Company
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An Element-Free Galerkin-Finite Element Coupling Method for Elasto-Plastic Contact Problems
Journal of Tribology, 2005Co-Authors: Tianxiang Liu, Geng Liu, Q. Jane WangAbstract:The element-free Galerkin-finite element (EFG-FE) coupling method, combined with the linear mathematical programming technique, is utilized to solve two-dimensional elasto-Plastic Contact problems. Two discretized models for an elastic cylinder Contacting with a rigid plane are used to investigate the boundary effects in a Contact problem when using the EFG-FE coupling method under symmetric conditions. The influences of the number of Gauss integration points and the size supporting the weight function in the meshless region on the Contact pressure and stress distributions are studied and discussed by comparing the numerical results with the theoretical ones. Furthermore, the elasto-Plastic Contact problems of a smooth cylinder with a plane and a rough surface with a plane are analyzed by means of the EFG-FE method and different elasto-Plasticity models.
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Elasto-Plastic Contact of Rough Surfaces
Tribology Transactions, 2001Co-Authors: Geng Liu, Jun Zhu, Q. Jane WangAbstract:An isothermal elasto-Plastic asperity Contact model is developed and presented in this paper, which deals with micro Plastic flows of materials and the influence of the elasto-Plastic deformation of materials on the behavior of Contacting surfaces. The model is solved with the incremental form of a simplex-type algorithm. The von Mises yield criterion is used to determine the onset of the Plastic deformation. The effectiveness and validity of the model are studied through analyzing a Hertzian Contact problem. Substrate stresses are calculated and differences are observed. Furthermore, the Contact pressure, real area of Contact, and average gap of real rough surfaces under the elastic, elastic-perfectly-Plastic, and the elasto-Plastic Contact conditions are numerically investigated and the results are compared. Presented at the 56th Annual Meeting Orlando, Florida May 20–24, 2001
Geng Liu - One of the best experts on this subject based on the ideXlab platform.
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Two-dimensional steady-state thermal elasto-Plastic Contact of rough surfaces
Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2008Co-Authors: Geng Liu, Tianxiang Liu, Qin Xie, Q J WangAbstract:A finite-element deterministic two-dimensional thermal elasto-Plastic Contact model is presented in this article, which facilitates the investigation of the influence of steady-state frictional heating on Contacting asperities and subsurface stress fields. This model takes into account the asperity distortion caused by the temperature variation in a tribological process, microPlastic flow of surface asperities, and coupled thermo-elasto-Plastic behaviour of the material, with and without considering the strain-hardening property of the material. The model is verified through the Contact analysis of a rigid, isothermal cylinder with a thermally conductive, elasto-Plastic plane. The maximum Contact pressures increase with frictional heating. Furthermore, thermal effects on the Contact pressure, real area of the Contact, and average gap of a real rough surface with different frictional heat inputs under thermal elasto-Plastic Contact conditions are numerically investigated. It indicates that neglecting therm...
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Elastic-Plastic Contact analysis of materials with gradient yield strength
Materials Science Forum, 2006Co-Authors: Qin Xie, Geng Liu, Tianxiang Liu, Jane Q. WangAbstract:Reported in the paper is an elastic-Plastic Contact model developed to analyze the Contact performance characteristics of materials with gradient yield strength. Plastic yielding and the strain-hardening properties of the materials are taken into account. The finite element method, the initial stiffness method, and a mathematical programming technique are utilized to solve the Contact model. The von Mises yield criterion is used to determine the inception of Plastic deformation. Results indicate that nitrided material with appropriate gradient of yield strength may greatly alter the distributions of Contact stress, Contact pressure as compared with untreated material in Contact. The effects of different yield strength variation path of material on von Mises stress distributions are numerically investigated and discussed.
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An Element-Free Galerkin-Finite Element Coupling Method for Elasto-Plastic Contact Problems
Journal of Tribology, 2005Co-Authors: Tianxiang Liu, Geng Liu, Q. Jane WangAbstract:The element-free Galerkin-finite element (EFG-FE) coupling method, combined with the linear mathematical programming technique, is utilized to solve two-dimensional elasto-Plastic Contact problems. Two discretized models for an elastic cylinder Contacting with a rigid plane are used to investigate the boundary effects in a Contact problem when using the EFG-FE coupling method under symmetric conditions. The influences of the number of Gauss integration points and the size supporting the weight function in the meshless region on the Contact pressure and stress distributions are studied and discussed by comparing the numerical results with the theoretical ones. Furthermore, the elasto-Plastic Contact problems of a smooth cylinder with a plane and a rough surface with a plane are analyzed by means of the EFG-FE method and different elasto-Plasticity models.
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Thermal Elasto-Plastic Contact Model of Rough Surfaces
World Tribology Congress III Volume 1, 2005Co-Authors: Geng Liu, Tianxiang Liu, Qin Xie, Fanghui ShiAbstract: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.Copyright © 2005 by ASME
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Elasto-Plastic Contact of Rough Surfaces
Tribology Transactions, 2001Co-Authors: Geng Liu, Jun Zhu, Q. Jane WangAbstract:An isothermal elasto-Plastic asperity Contact model is developed and presented in this paper, which deals with micro Plastic flows of materials and the influence of the elasto-Plastic deformation of materials on the behavior of Contacting surfaces. The model is solved with the incremental form of a simplex-type algorithm. The von Mises yield criterion is used to determine the onset of the Plastic deformation. The effectiveness and validity of the model are studied through analyzing a Hertzian Contact problem. Substrate stresses are calculated and differences are observed. Furthermore, the Contact pressure, real area of Contact, and average gap of real rough surfaces under the elastic, elastic-perfectly-Plastic, and the elasto-Plastic Contact conditions are numerically investigated and the results are compared. Presented at the 56th Annual Meeting Orlando, Florida May 20–24, 2001
