scholarly journals A friction model of fractal rough surfaces accounting for size dependence at nanoscale

2022 ◽  
Author(s):  
X. M. Liang ◽  
G. F. Wang
Keyword(s):  
Size Dependence ◽  
Rough Surfaces ◽  
Friction Model

scholarly journals A Static Friction Model for Unlubricated Contact of Random Rough Surfaces at Micro/Nano Scale

Micromachines ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 368
Author(s):  
Shengguang Zhu ◽  
Liyong Ni
Keyword(s):  
Rough Surfaces ◽  
Static Friction ◽  
Friction Model ◽  
Elastic Contact ◽  
Nano Scale ◽  
Random Rough Surfaces ◽  
Proposed Model ◽  
Dissipation Mechanism ◽  
Rigid Plane ◽  
Contact Situation

A novel static friction model for the unlubricated contact of random rough surfaces at micro/nano scale is presented. This model is based on the energy dissipation mechanism that states that changes in the potential of the surfaces in contact lead to friction. Furthermore, it employs the statistical theory of two nominally flat rough surfaces in contact, which assumes that the contact between the equivalent rough peaks and the rigid flat plane satisfies the condition of interfacial friction. Additionally, it proposes a statistical coefficient of positional correlation that represents the contact situation between the equivalent rough surface and the rigid plane. Finally, this model is compared with the static friction model established by Kogut and Etsion (KE model). The results of the proposed model agree well with those of the KE model in the fully elastic contact zone. For the calculation of dry static friction of rough surfaces in contact, previous models have mainly been based on classical contact mechanics; however, this model introduces the potential barrier theory and statistics to address this and provides a new way to calculate unlubricated friction for rough surfaces in contact.

A Novel Dynamic Friction Model Based on Asperity Creep

2008 ◽  
Author(s):  
Andreas Goedecke ◽  
Randolf Mock
Keyword(s):  
Friction Coefficient ◽  
Rough Surfaces ◽  
Fractal Model ◽  
Friction Model ◽  
Test Case ◽  
Dynamic Friction ◽  
Surface Asperity ◽  
Perfectly Plastic ◽  
Novel Approach ◽  
Asperity Model

We present a novel approach for the simulation of dynamic friction in engineering systems, based on a new surface asperity model including creep effects. Our novel friction model aims at understanding the link between the microscopic origins of friction dynamics and the response of the engineering-level friction induced vibrations. The approach is based on the assumption that the time- and velocity-dependent friction coefficient is mainly caused by creep growth of surface asperity contacts (microscopic contact patches between two rough surfaces) as proposed by Kragelskii, Rabinowicz, Scholz and others. At the heart of our approach is a new asperity model that includes creep effects. Based on the pioneering work of Etsion et al., we conducted extensive FEM simulations to analyze the creep behavior of an elastic-perfectly plastic hemisphere in contact with a rigid flat. The new asperity model is used as a building block for a fractal model for the contact between rough surfaces. The model yields the time- and velocity-dependent macroscopic friction coefficient. We demonstrate the practical applicability of the new dynamic friction model in a simple block-on-conveyor test case to analyze friction induced vibrations.

A Static Friction Model for Elastic-Plastic Contacting Rough Surfaces

2004 ◽  
Vol 126 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Lior Kogut ◽  
Izhak Etsion
Keyword(s):  
Friction Coefficient ◽  
Rough Surfaces ◽  
Static Friction ◽  
Friction Model ◽  
Plasticity Index ◽  
High Plasticity ◽  
Elastic Plastic ◽  
Static Friction Coefficient ◽  
Contact Adhesion ◽  
Limiting Case

A model that predicts the static friction for elastic-plastic contact of rough surfaces is presented. The model incorporates the results of accurate finite element analyses for the elastic-plastic contact, adhesion and sliding inception of a single asperity in a statistical representation of surface roughness. The model shows strong effect of the external force and nominal contact area on the static friction coefficient in contrast to the classical laws of friction. It also shows that the main dimensionless parameters affecting the static friction coefficient are the plasticity index and adhesion parameter. The effect of adhesion on the static friction is discussed and found to be negligible at plasticity index values larger than 2. It is shown that the classical laws of friction are a limiting case of the present more general solution and are adequate only for high plasticity index and negligible adhesion. Some potential limitations of the present model are also discussed pointing to possible improvements. A comparison of the present results with those obtained from an approximate CEB friction model shows substantial differences, with the latter severely underestimating the static friction coefficient.

A Kinetic Friction Model for Viscoelastic Contact of Nominally Flat Rough Surfaces

2007 ◽  
Vol 129 (3) ◽  
pp. 684-688 ◽  
Author(s):  
K. Farhang ◽  
A. Lim
Keyword(s):  
Contact Force ◽  
Rough Surfaces ◽  
Tangential Force ◽  
Tangential Velocity ◽  
Surface Profile ◽  
Friction Model ◽  
Contact Forces ◽  
Profile Measurement ◽  
Tangential Contact ◽  
Force Velocity

Approximate closed-form equations are derived for normal and tangential contact forces of rough surfaces in dry friction. Using an extension of the Greenwood and Tripp (1970, Proc, Inst. Mech. Eng., 185, pp. 625–633) model, in which the derivations permit asperity shoulder-to-shoulder contact and viscoelastic asperity behavior, mathematical formulae are derived for normal and tangential components of the contact force that depend not only on the proximity of the two surfaces but also the rate of approach and relative sliding. A statistical approach is forwarded in which dependence of the asperity tangential contact force on relative tangential velocity of two asperities can be cast as corrective factors in the mathematical description of tangential force. In this regard two corrective coefficients are derived: force directionality corrective coefficient and force–velocity directionality corrective coefficient. The results show that for a moderate to high load ranges the contact force can be analytically described to within 20% accuracy of that from a numerical integration of the contact equations, well below the uncertainties due to surface profile measurement.

Fractal Friction Model of Elliptic Rough Surfaces with a Hard Coating Film

2012 ◽  
Vol 12 (1) ◽  
pp. 451-456
Author(s):  
J. H. Horng ◽  
S. Y. Chern ◽  
C. H. Wu
Keyword(s):  
Rough Surfaces ◽  
Friction Model ◽  
Hard Coating ◽  
Coating Film

A Numerical Static Friction Model for Spherical Contacts of Rough Surfaces, Influence of Load, Material, and Roughness

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
W. Wayne Chen ◽  
Q. Jane Wang
Keyword(s):  
Shear Strength ◽  
Rough Surfaces ◽  
Normal Load ◽  
Tangential Force ◽  
Dissimilar Materials ◽  
Static Friction ◽  
Friction Model ◽  
Friction Mechanism ◽  
Upper Limits ◽  
Rough Surface Contact

The relative motion between two surfaces under a normal load is impeded by friction. Interfacial junctions are formed between surfaces of asperities, and sliding inception occurs when shear tractions in the entire contact area reach the shear strength of the weaker material and junctions are about to be separated. Such a process is known as a static friction mechanism. The numerical contact model of dissimilar materials developed by the authors is extended to evaluate the maximum tangential force (in terms of the static friction coefficient) that can be sustained by a rough surface contact. This model is based on the Boussinesq–Cerruti integral equations, which relate surface tractions to displacements. The materials are assumed to respond elastic perfectly plastically for simplicity, and the localized hardness and shear strength are set as the upper limits of contact pressure and shear traction, respectively. Comparisons of the numerical analysis results with published experimental data provide a validation of this model. Static friction coefficients are predicted for various material pairs in contact first, and then the behaviors of static friction involving rough surfaces are extensively investigated.

Infrared spectra of carbon monoxide on platinum, iridium and copper ; comparison of flat and rough surfaces

1981 ◽  
Vol 78 ◽  
pp. 927-932 ◽  
Author(s):  
F.J.C.M. Toolenaar ◽  
G.J. van der Poort ◽  
F. Stoop ◽  
V. Ponec
Keyword(s):  
Carbon Monoxide ◽  
Infrared Spectra ◽  
Rough Surfaces

OPTICAL PROPERTIES OF THIN FILMS ON ROUGH SURFACES

1983 ◽  
Vol 44 (C10) ◽  
pp. C10-363-C10-366 ◽  
Author(s):  
J. Vlieger ◽  
M. M. Wind
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Rough Surfaces
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