A Nano-Scale Multi-Asperity Model for Contact and Friction

2002 ◽  
Author(s):  
George G. Adams ◽  
Sinan Mu¨ftu¨ ◽  
Nazif Mohd Azhar
Keyword(s):  
Normal Force ◽  
Real Contact Area ◽  
Adhesion Forces ◽  
Friction Forces ◽  
Dugdale Model ◽  
Single Asperity ◽  
Nano Scale ◽  
Macro Scale ◽  
Asperity Contacts ◽  
Asperity Model

As surfaces become smoother and loading forces decrease in applications such as MEMS and NEMS devices, the asperity contacts which comprise the real contact area will continue to decrease into the nano scale regime. Thus it becomes important to understand how the material and topographical properties of surfaces contribute to measured friction forces at this nano scale. We have incorporated the single asperity nano contact model of Hurtado and Kim into a multi-asperity model for contact and friction which includes the effect of asperity adhesion forces using the Maugis-Dugdale model. Our model spans the range from nano-scale to micro-scale to macro-scale contacts. We have identified three key dimensionless parameters representing combinations of surface roughness measures, Burgers vector length, surface energy, and elastic modulus. Results are given for the normal and friction forces vs. separation, and for the friction coefficient vs. normal force for various values of these key parameters.

A Nano-Scale Multi-Asperity Contact and Friction Model

2002 ◽  
Author(s):  
George G. Adams ◽  
Sinan Mu¨ftu¨ ◽  
Nazif Mohd Azhar
Keyword(s):  
Friction Model ◽  
Real Contact Area ◽  
Asperity Contact ◽  
Adhesion Forces ◽  
Friction Forces ◽  
Dugdale Model ◽  
Nano Scale ◽  
Macro Scale ◽  
Asperity Contacts ◽  
Asperity Model

As surfaces become smoother and loading forces decrease in applications such as MEMS and NEMS devices, the asperity contacts which comprise the real contact area will continue to decrease into the nano scale regime. Thus it becomes important to understand how the material and topographical properties of surfaces contribute to measured friction forces at this nano scale. We have incorporated the single asperity nano contact model of Hurtado and Kim into a multi-asperity model for contact and friction which includes the effect of asperity adhesion forces using the Maugis-Dugdale model. Our model spans the range from nano-scale to micro-scale to macro-scale contacts. We have identified three key dimensionless parameters representing combinations of surface roughness measures, Burgers vector length, surface energy, and elastic modulus. Results are given for the normal and friction forces vs. separation, and for the friction coefficient vs. normal force for various values of these key parameters.

A Scale-Dependent Model for Multi-Asperity Contact and Friction

2003 ◽  
Vol 125 (4) ◽  
pp. 700-708 ◽  
Author(s):  
George G. Adams ◽  
Sinan Mu¨ftu¨ ◽  
Nazif Mohd Azhar
Keyword(s):  
Real Contact Area ◽  
Asperity Contact ◽  
Adhesion Forces ◽  
Friction Forces ◽  
Dugdale Model ◽  
The Real ◽  
Nano Scale ◽  
Macro Scale ◽  
Asperity Contacts ◽  
Coefficient Versus

As loading forces decrease in applications such as MEMS and NEMS devices, the size of the asperity contacts which comprise the real contact area tend to decrease into the nano scale regime. This reduction in size of the contacts is only partially offset by the nominally increased smoothness of these contacting surfaces. Because the friction force depends on the real area of contact, it is important to understand how the material and topographical properties of surfaces contribute to friction forces at this nano scale. In this investigation, the single asperity nano contact model of Hurtado and Kim is incorporated into a multi-asperity model for contact and friction which includes the effect of asperity adhesion forces using the Maugis-Dugdale model. The model spans the range from nano-scale to micro-scale to macro-scale contacts. Three key dimensionless parameters have been identified which represent combinations of surface roughness measures, Burgers vector length, surface energy, and elastic properties. Results are given for the friction coefficient versus normal force, the normal and friction forces versus separation, and the pull-off force for various values of these key parameters.

scholarly journals Effect of Normal Contact Vibration on Nano-Scale Friction

Lubricants ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 99
Author(s):  
Jae Hyeok Choi ◽  
Su Kyeong Kwan ◽  
Hui Eun Ko ◽  
Jeong Hyun Park ◽  
Dong Keun Kim ◽  
...  
Keyword(s):  
Interaction Potential ◽  
Vibration Amplitude ◽  
Normal Force ◽  
Sliding Velocity ◽  
Normal Contact ◽  
Single Asperity ◽  
Wide Range ◽  
Asperity Contacts ◽  
Oscillation Velocity ◽  
Logarithmic Relationship

In this work, we investigate the effect of contact vibration on the friction of sliding single asperity contacts of different adhesion strength over a wide range of load and vibration amplitude. We convert the amplitude of vibration to its equivalent modulation force and tip-oscillation velocity. We observe a logarithmic relationship between friction and the ratio of the modulation force to the normal force and between friction and the ratio of sliding velocity to the tip-oscillation velocity. We discuss these logarithmic dependencies based on an induced corrugation of the tip-sample interaction potential.

Asperity-Based Models of Micro-Scale Friction

2005 ◽  
Author(s):  
George G. Adams
Keyword(s):  
Contact Area ◽  
Tangential Force ◽  
Scale Dependence ◽  
Real Contact Area ◽  
Nonlinear Load ◽  
Friction Forces ◽  
Micro Scale ◽  
Load Dependence ◽  
Real Contact ◽  
Asperity Contacts

As surfaces become smoother and loading forces decrease in applications such as MEMS, NEMS, and magnetic recording devices, the size and number of the asperity contacts which comprise the real contact area continues to decrease. The tangential force which is measured between two sliding bodies is the combined result of friction forces which are present in a very large number of nano and micro scale asperity contacts. Recent experiments as well as modeling have shown considerable scale-dependence and nonlinear load-dependence of the friction force. These models will be reviewed and discussed.

Simulation of Nanomanipulation Using Compliance-Based Contact Dynamics Modeling Technique

2007 ◽  
Author(s):  
Ou Ma ◽  
Xiumin Diao ◽  
Mingjun Zhang
Keyword(s):  
Contact Forces ◽  
Contact Dynamics ◽  
Modeling Technique ◽  
Published Data ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Friction Forces ◽  
Nano Scale ◽  
Model Fidelity ◽  
Macro Scale

This paper describes dynamics modeling and simulation of AFM-based manipulation of a nano-scale object using the compliance-based contact dynamics modeling technique (also referred to as the penalty method). Such a modeling technique has been well developed and widely applied in macro-scale applications. Its applicability to nano-scale cases is, however, relatively new and thus, requires more investigation. The dynamics model developed in the paper includes the Van der Waals forces, electrostatic forces, contact forces (for modeling repulsion), and friction forces with consideration of contact geometry, stiffness, and friction properties of all the physically interacting objects. The model can simulate the dynamic behavior of interactions between nano-scale objects and its environment. For demonstration, the dynamic simulation results of an AFM-based manipulation process are presented. To provide confidence of the model fidelity, a simulation example which matches some published data is presented.

Identifying Product Scaling Principles: A Tool for Bioinspired Design and Beyond

2011 ◽  
Author(s):  
Angel G. Perez ◽  
Julie S. Linsey
Keyword(s):  
Scaling Laws ◽  
Initial Step ◽  
Nano Scale ◽  
Bioinspired Design ◽  
Macro Scale ◽  
Design By Analogy ◽  
Global Principles ◽  
Physical Principles

There are countless products that perform the same function but are engineered to suit a different scale. Designers are often faced with the problem of taking a solution at one scale and mapping it to another. This frequently happens with design-by-analogy and bioinspired design. Despite various scaling laws for specific systems, there are no global principles for scaling systems, for example from a biological nano-scale to macro-scale. This is likely one of the reasons bioinspired design is difficult. Very often scaling laws assume the same physical principles are being used, but this study of products indicates that a variety of changes occur as scale changes, including changing the physical principles to meet a particular function. Empirical product research was used to determine a set of principles by observing and understanding numerous products to unearth new generalizations. The function a product performs is examined in various scales to view subtle and blatant differences. Principles are then determined. This study provides an initial step in creating new innovative designs based on existing solutions in nature or other products that occur at very different scales. Much further work is needed by studying additional products and bioinspired examples.

Electric Control of Friction on Silicon Studied by Atomic Force Microscope

NANO ◽  
2015 ◽  
Vol 10 (03) ◽  
pp. 1550038 ◽  
Author(s):  
Yan Jiang ◽  
Lili Yue ◽  
Boshen Yan ◽  
Xi Liu ◽  
Xiaofei Yang ◽  
...  
Keyword(s):  
Atomic Force Microscope ◽  
Bias Voltage ◽  
Electrostatic Force ◽  
Adhesion Forces ◽  
Friction Forces ◽  
Type Silicon ◽  
Atomic Force ◽  
Electric Control ◽  
Before And After ◽  
Track Line

We investigated friction on an n-type silicon surface using an atomic force microscope when a bias voltage was applied to the sample. Friction forces on the same track line were measured before and after the bias voltages were applied and it was found that the friction forces in n-type silicon can be tuned reversibly with the bias voltage. The dependence of adhesion forces between the silicon nitride tip and Si sample on the bias voltages approximately follows a parabolic law due to electrostatic force, which results in a significant increase in the friction force at an applied electric field.

Influence of the Powder Particle Size on the Denudated Zone Width at Selective Laser Melting

2020 ◽  
Vol 989 ◽  
pp. 816-820
Author(s):  
Roman Sergeevich Khmyrov ◽  
R.R. Ableyeva ◽  
Tatiana Vasilievna Tarasova ◽  
A.V. Gusarov
Keyword(s):  
Particle Size ◽  
Selective Laser Melting ◽  
Powder Particle ◽  
Powder Particle Size ◽  
Adhesion Forces ◽  
Laser Melting ◽  
Friction Forces ◽  
Single Bead ◽  
Powder Particles

Mass transfer in the laser-interaction zone at selective laser melting influences the quality of the obtained material. Powder particles displacement during the formation of the single bead is experimentally studied. The so-called denudated zone was visualized by metallography. It was determined that increasing the powder particle size leads to widening the denudated zone. This can signify that the adhesion forces between powder particles prevail over the friction forces.

Temperature-induced switchable interfacial interactions on slippery surfaces for controllable liquid manipulation

2019 ◽  
Vol 7 (31) ◽  
pp. 18510-18518 ◽  
Author(s):  
Zubin Wang ◽  
Quan Xu ◽  
Lili Wang ◽  
Liping Heng ◽  
Lei Jiang
Keyword(s):  
Interfacial Friction ◽  
Adhesion Forces ◽  
Interfacial Interactions ◽  
Friction Forces ◽  
Temperature Responsive ◽  
Slippery Surface

The interfacial friction forces and adhesion forces are directly detected and controllable liquid sliding is achieved on a temperature-responsive slippery surface.

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