A new elliptical microcontact model considering elastoplastic deformation

2018 ◽  
Vol 232 (11) ◽  
pp. 1352-1364 ◽  
Author(s):  
Yuqin Wen ◽  
Jinyuan Tang ◽  
Wei Zhou ◽  
Caichao Zhu
Keyword(s):  
Rough Surface ◽  
Contact Pressure ◽  
Elastoplastic Deformation ◽  
Height Distribution ◽  
New Model ◽  
Surface Contact ◽  
Calculation Results ◽  
The Mean ◽  
Rough Surface Contact ◽  
Change Curve

A new elliptical microcontact model considering elastoplastic deformation is proposed to overcome the shortcomings of the existing elastoplastic microcontact model. A new low-order interpolation function is used to describe the relationship between the normal deformation of asperity and the mean contact pressure in the elastoplastic deformation stage, and a smooth, continuous, monotonic change curve of the mean contact pressure is obtained. Then, the contact of rough surfaces is studied based on the new elastoplastic elliptical microcontact model and the height distribution of asperity. The calculated results are compared with those obtained from the existing rough surface contact models and the comparisons show that: (1) the change curve for the average contact pressure in the new model is smooth, continuous, and monotonic; (2) the calculation results of the new model are consistent with the numerical results based on the finite element method; (3) the new model is helpful to study the rough surface contact analysis of the elliptical micro-convex body.

A Rough Surface Contact Model for General Anisotropic Materials

2004 ◽  
Vol 126 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Yuan Lin ◽  
Timothy C. Ovaert
Keyword(s):  
Rough Surface ◽  
Half Space ◽  
Contact Pressure ◽  
Surface Displacement ◽  
Anisotropic Materials ◽  
Elastic Half Space ◽  
Iteration Scheme ◽  
Real Contact Area ◽  
Surface Contact ◽  
Rough Surface Contact

A method for solving the two-dimensional (2-D) isothermal rough surface contact problem of general anisotropic materials with friction is presented. By using Stroh’s formalism, the surface displacements of an elastic half-space due to uniform distributions of traction over a strip are derived from the surface Green’s function. The surface displacement and subsurface stresses of the anisotropic half-space due to the distributed contact pressure may then be calculated by superposition. The real contact area and the contact pressure are determined via an iteration scheme using the conjugate gradient method.

Numerical Contact Model of a Smooth Ball on an Anisotropic Rough Surface

1994 ◽  
Vol 116 (2) ◽  
pp. 194-201 ◽  
Author(s):  
C. Y. Poon ◽  
R. S. Sayles
Keyword(s):  
Rough Surface ◽  
Contact Pressure ◽  
Smooth Surface ◽  
Contact Model ◽  
The Real ◽  
Numerical Result ◽  
Realistic Situation ◽  
Surface Contact ◽  
Rough Surface Contact ◽  
Sinusoidal Surface

A numerical elastic-plastic contact model of a smooth ball on a directionally structured anisotropic rough surface is presented. The contact model is tested on three types of surface contact of a smooth ball on (i) a smooth surface, (ii) a sinusoidal surface, and (iii) a real rough surface. The validity of the model is proven by good agreement of the numerical result for the smooth surface with the Hertz analytical result. The contact of the sinusoidal surface shows that by the introduction of surface undulation in a regular pattern, the real pressure distribution follows the expected behavior where the contact pressure at the peak is maximum and the contact pressure at the valley is zero and the peak pressure decreases away from the ball center. The contact of the real rough surface shows the ability of the model to cope with the more practically realistic situation where the asperity heights are distributed randomly. The results of the rough surface contact analysis for different surface roughness are presented in a separate paper.

Design Optimization of Ultra-Low Flying Head-Disk Interfaces Using an Improved Elastic-Plastic Rough Surface Model

2006 ◽  
Vol 128 (4) ◽  
pp. 801-810 ◽  
Author(s):  
Allison Y. Suh ◽  
Sung-Chang Lee ◽  
Andreas A. Polycarpou
Keyword(s):  
Rough Surface ◽  
Contact Pressure ◽  
Surface Model ◽  
Successful Implementation ◽  
Contact Conditions ◽  
Friction Forces ◽  
Interfacial Forces ◽  
Elastic Plastic ◽  
The Mean ◽  
Improved Model

Sub-5nm flying head-disk interfaces (HDIs) designed to attain extremely high areal recording densities of the order of Tbit∕in2 are susceptible to strong adhesive forces, which can lead to subsequent contact, bouncing vibration, and high friction. Accurate prediction of the relevant interfacial forces can help ensure successful implementation of ultra-low flying HDIs. In this study, an improved rough surface model is developed to estimate the adhesive, contact, and friction forces as well as the mean contact pressure relevant to sub-5nm HDIs. The improved model was applied to four different HDIs of varying roughness and contact conditions, and was compared to the sub-boundary lubrication rough surface model. It was found that the interfacial forces in HDIs undergoing primarily elastic-plastic and plastic contact are more accurately predicted with the improved model, while under predominantly elastic contact conditions, the two models give similar results. The improved model was then used to systematically investigate the effect of roughness parameters on the interfacial forces and mean contact pressure (response). The trends in the responses were investigated via a series of regression models using a full 33 factorial design. It was found that the adhesive and net normal interfacial forces increase with increasing mean radius R of asperities when the mean separation is small (≈0.5nm), i.e., pseudo-contacting interface, but it increases primarily with increasing root-mean-square (rms) surface height roughness between 2 and 4nm, i.e., pseudo-flying interface. Also, increasing rms roughness and decreasing R, increases the contact force and mean contact pressure, while the same design decreases the friction force. As the directions of optimization for minimizing the individual interfacial forces are not the same, simultaneous optimization is required for a successful ultra-low flying HDI design.

Lubrication of Rough Surfaces by a Boundary Film-Forming Viscosity Modifier Additive

2005 ◽  
Vol 127 (1) ◽  
pp. 223-229 ◽  
Author(s):  
R. P. Glovnea ◽  
A. V. Olver ◽  
H. A. Spikes
Keyword(s):  
Rough Surface ◽  
Rough Surfaces ◽  
Viscosity Index ◽  
Functionalized Polymers ◽  
Contact Conditions ◽  
Film Forming ◽  
Boundary Film ◽  
Surface Contact ◽  
Lubricated Contact ◽  
Rough Surface Contact

In previous work it was shown that some functionalized polymers used as viscosity index improvers are able to form thick boundary lubricating films. This behavior results from adsorption of the polymer on metal surfaces to form a layer of enhanced viscosity adjacent to the surface. In the current work the behavior of one such polymer in rough surface contact conditions is studied, using both model and real rough surfaces. It is found that the polymer is able to form a thick boundary film in rough surface contact, just as it does with smooth surfaces. It is also shown that the effect of this boundary film is to significantly reduce friction in rolling-sliding, rough surface, lubricated contact.

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