Elastic–Plastic Spherical Contact Modeling Including Roughness Effects (original) (raw)
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Elastic-Plastic Contact Analysis of a Sphere and a Rigid Flat
Journal of Applied Mechanics, 2002
An elastic-plastic finite element model for the frictionless contact of a deformable sphere pressed by a rigid flat is presented. The evolution of the elastic-plastic contact with increasing interference is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. The model provides dimensionless expressions for the contact load, contact area, and mean contact pressure, covering a large range of interference values from yielding inception to fully plastic regime of the spherical contact zone. Comparison with previous elastic-plastic models that were based on some arbitrary assumptions is made showing large differences.
On the tangential contact behavior at elastic-plastic spherical contact problems
2014
The problem of tangential contact between an elastic-plastic sphere and a rigid plane is studied analytically and numerically with the specific aim to derive force-displacement relations to be used in numerical simulations of granular materials. The simulations are performed for both ideal-plastic and strain hardening materials with different yield stresses and including large deformation effects in order to draw general conclusions. The results are correlated using normalized quantities pertinent to the correlation of indentation testing experiments leading to a general description of the tangential contact problem. Explicit formulas for the normal and tangential forces are presented as a function of the tangential displacement using data that are easily available from axi-symmetric analyses of spherical contact. The proposed model shows very good agreement when compared with the FE-simulations.
Experimental Investigation of Fully Plastic Contact of a Sphere Against a Hard Flat
Journal of Tribology, 2006
In this paper we report the experimental investigation to evaluate the published models for the contact of a deformable sphere against a hard flat in the fully plastic contact regime. A new measurement method has been used to measure the contact area. The behavior of the mean contact pressure and the contact area as a function of the contact load are presented. Substantial differences are found between the measurements and the model predictions. A constant value of the mean contact pressure as the load increases is observed, however, the value is lower than the hardness, as often reported. The contact area is found to be a simple truncation of the sphere by a hard flat.
Finite Element based Elastic-Plastic Contact Behaviour of a Sphere against a Rigid Flat – Effect
2014
Abstract—The present study considers an elastic-plastic contact analysis of a deformable sphere with a rigid flat using finite element method. The effect of strain hardening on the contact behaviour of a non-adhesive frictionless elastic-plastic contact is analyzed using commercial finite element software ANSYS. To study the strain hardening effect we have taken different values of tangent modulus. The result of strain hardening effect clearly shows that a generalized solution can not be applicable for all kind of materials as the effect of strain hardening differently influenced the contact parameters. With the increase in the value of hardening parameter this effect also increases. For higher value of hardening parameter the effect of strain hardening is severe on contact parameters. With the increase in strain hardening the resistance to deformation of a material is increased and the material becomes capable of carrying higher amount of load in a smaller contact area. I.
The effect of contact conditions and material properties on elastic-plastic spherical contact
Journal of Mechanics of Materials and Structures, 2006
The aim of this article is to give a detailed account of the plane harmonic generalized elasto-thermodiffusive (ETNP) waves in semiconductive materials. The shear (purely transverse) waves get decoupled from the rest of the motion and remain independent of the influence of other fields. These waves propagate without dispersion and attenuation in semiconductors. The coupled system of partial differential equations, governing the rest of the interacting fields, has been solved to obtain a complex secular equation. According to the frequency equation, four coupled longitudinal waves, namely, the quasithermoelastic (QTE), quasielastodiffusive (QEN/QEP), quasithermodiffusive (QTN/QTP), and quasithermal (T-mode), can exist and propagate in an infinite semiconductor. The complex secular equation of plane harmonic waves in semiconductors is solved by using Descartes' algorithm and the irreducible case of Cardan's method in order to obtain phase velocities and attenuation coefficients of all possible coupled waves. The thermoelastic (ET), elastodiffusive (EN/EP) and thermodiffusive (TN/TP) waves have also been investigated as special cases. The derived theoretical results have been illustrated and verified numerically for germanium (Ge) and silicon (Si) semiconductors. The computed phase velocity and attenuation profiles have been presented graphically.
2010
The present study considers an elastic-plastic contact analysis of a deformable sphere with a rigid flat using finite element method. The effect of strain hardening on the contact behaviour of a non-adhesive frictionless elastic-plastic contact is analyzed using commercial finite element software ANSYS. To study the strain hardening effect we have taken different values of tangent modulus. The result of strain hardening effect clearly shows that a generalized solution can not be applicable for all kind of materials as the effect of strain hardening differently influenced the contact parameters. With the increase in the value of hardening parameter this effect also increases. For higher value of hardening parameter the effect of strain hardening is severe on contact parameters. With the increase in strain hardening the resistance to deformation of a material is increased and the material becomes capable of carrying higher amount of load in a smaller contact area.
Elastic–plastic spherical contact under combined normal and tangential loading in full stick
Tribology Letters, 2006
The behavior of an elastic-plastic contact between a deformable sphere and a rigid flat under combined normal and tangential loading with full stick contact condition is investigated theoretically. Sliding inception is treated as a plastic yield failure mechanism, which allows static friction modeling under highly adhesive conditio ns. Several contact parameters such as: junction tangential stiffness, static friction force and static friction coefficient are extensively investigated. The phenomenon of junction growth and the evolution of the plastic zone in the contact region are briefly described. It is found that at low normal dimensionless loads the static friction coefficient decreases sharply with increasing normal load, in breach with the classical laws of friction. As the normal load further increases the static friction coefficient approaches a constant value that is about 0.3 for many material properties combinations.
A Finite Element-Based Elastic-Plastic Model for the Contact of Rough Surfaces
Modelling and Simulation in Engineering, 2011
An elastic-plastic model for contacting rough surfaces that is based on accurate Finite Element Analysis (FEA) of an elasticplastic single asperity contact is presented. The plasticity index Ψ is shown to be the main dimensionless parameter that affects the contact of rough surfaces. Below Ψ = 0.6 the contact problem is purely elastic and above Ψ = 8 it is mostly plastic. The mean real contact pressure is found to be practically independent of the contact load, similarly to the material hardness in fully plastic contact. An "elastic-plastic hardness" in the form 0.4 1/Ψ H can therefore be used to relate the contact load and real area of contact. A comparison with the approximate CEB (Chang, Etsion, Bogy) model shows identical results for pure elastic contacts having plasticity index values below 0.6 but substantial differences for elastic-plastic contacts having plasticity index values above 1.