An Extension to a Cohesive Zone Solution for Adhesive Cylinders

2004 ◽  
Author(s):  
Clint A. Morrow ◽  
Michael R. Lovell
Keyword(s):  
Cohesive Zone ◽  
Normal Load ◽  
Adhesive Contact ◽  
Physical Contact ◽  
Contact Radius ◽  
Intimate Contact ◽  
Contact Behavior ◽  
Micro Scale ◽  
Applied Normal Load ◽  
Adhesive Forces

When adhesive forces are taken into consideration, contacting asperities can still interact after intimate contact is broken. Current theories that predict the contact behavior of adhesive cylindrical asperities fail to capture the forces in this regime. In the present investigation, prior solutions for adhesive cylindrical asperities will be extended to include the condition where the asperities are not in physical contact but are still interacting through adhesive forces. In the extended results, relationships between the adhesive contact radius and the applied normal load will be developed and discussed with respect to the design of micro-scale components.

An Extension to a Cohesive Zone Solution for Adhesive Cylinders

2005 ◽  
Vol 127 (2) ◽  
pp. 447-450 ◽  
Author(s):  
Clint A. Morrow ◽  
Michael R. Lovell
Keyword(s):  
Cohesive Zone ◽  
Normal Load ◽  
Adhesive Contact ◽  
Physical Contact ◽  
Contact Radius ◽  
Intimate Contact ◽  
Contact Behavior ◽  
Micro Scale ◽  
Applied Normal Load ◽  
Adhesive Forces

When adhesive forces are taken into consideration, contacting asperities can still interact after intimate contact is broken. Current theories that predict the contact behavior of adhesive cylindrical asperities fail to capture the forces in this regime. In the present investigation, prior solutions for adhesive cylindrical asperities will be extended to include the condition where the asperities are not in physical contact but are still interacting through adhesive forces. In the extended results, relationships between the adhesive contact radius and the applied normal load will be developed and discussed with respect to the design of micro-scale components.

An Elastic Adhesion Model for Contacting Cylinder and Perfectly Wetted Plane in the Presence of Meniscus

2007 ◽  
Vol 129 (2) ◽  
pp. 231-234 ◽  
Author(s):  
Y. F. Peng ◽  
G. X. Li
Keyword(s):  
Relative Humidity ◽  
Normal Load ◽  
Adhesive Contact ◽  
Laplace Pressure ◽  
Contact Radius ◽  
Adhesive Interaction ◽  
Applied Normal Load ◽  
Adhesion Model ◽  
The Relationship

The present research concerns the elastic contacting adhesion of a cylinder with a perfectly wetted plane in the presence of a meniscus. The Laplace pressure due to the meniscus is simplified utilizing Maugis–Dugdale approximation. Then the Baney and Hui solution and its extension are used to solve the adhesive interaction of the cylinder and the plane. Simulations of the relationship between the adhesive contact radius and the applied normal load are performed, and the influence of the relative humidity on the relationship is also discussed.

Zero-Load Friction at Nanowire-Silicon Interfaces

2008 ◽  
Author(s):  
Mohan Manoharan ◽  
Aman Haque
Keyword(s):  
Normal Load ◽  
Static Friction ◽  
Force Sensor ◽  
Silicon Substrates ◽  
Ambient Conditions ◽  
Friction Forces ◽  
Oxide Nanowires ◽  
Applied Normal Load ◽  
Adhesion Friction ◽  
Adhesive Forces

The dominance of adhesive forces at the nanoscale implies that significant friction forces can be generated at the interface even with no externally applied normal load. We have nanofabricated an adhesion-friction force sensor to characterize friction in zinc oxide nanowires on silicon substrates. Experimental results show static friction coefficients for zero externally applied normal load can be as high as 45. This behavior is observed to be strongly influenced by the ambient conditions and we propose that the presence of molecularly thin moisture layers is responsible for the observed pseudo-static friction. The findings of this study will provide valuable input to nanoscale interfacial systems such as nanowires and nanotube based sensors and nanocomposites.

Contact Angle Manipulation for Liquid Bridge Based Microgripper

2007 ◽  
Author(s):  
Santanu Chandra ◽  
Celal Batur
Keyword(s):  
Contact Angle ◽  
Liquid Bridge ◽  
Feasible Solution ◽  
Scaling Law ◽  
Surface Tension Force ◽  
Release Mechanism ◽  
Cfd Analysis ◽  
Micro Scale ◽  
Young Equation ◽  
Adhesive Forces

Manipulation of micron sized components is essential for microassembly. Understanding the dominant adhesive forces in the micro-scale as well as devising techniques to control them is needed in order to design a proper micro manipulation apparatus. A liquid bridge based micromanipulation scheme is presented in this paper. The adhesive forces like capillary and surface tension force are prominent in micro scale due to scaling law and provides sufficient force for pickup of an object. The main problem resides in the systematic release of the object from the gripper surface. The focus of this paper is on the feasibility study of contact angle manipulation by electrowetting method for prompt release of an object. Preliminary results from numerical solution of Laplace-Young equation and CFD analysis shows that by increasing the contact angle a critical contact angle is reached after which Laplace-Young equation does not produce a feasible solution and the CFD analysis results in an unstable solution. This result demonstrates that the contact angle manipulation is capable of breaking a liquid bridge and provides a feasible solution for the release mechanism in microgripping.

Adhesive Contact Between Atomistic Surfaces Using a Continuum Analysis

2009 ◽  
Author(s):  
Simon Medina ◽  
Daniele Dini ◽  
Andrew V. Olver
Keyword(s):  
Adhesive Contact ◽  
Atomic Scale ◽  
Local Surface ◽  
Total Surface Energy ◽  
Complete Representation ◽  
Surface Separation ◽  
Continuum Analysis ◽  
Pressure Profiles ◽  
Dynamics Simulations ◽  
Adhesive Forces

We have previously shown that, for non-adhesive conditions, an atomic scale contact can be adequately represented by a continuum analysis despite the physical shortcomings at this scale. Here we have extended the approach to include effects of the adhesive forces that become significant at this level of contact. Adhesive forces are obtained directly from the surface separation across the contact rather than through a total surface energy approach; this allows a complete representation of local surface features. The pull-off characteristics and pressure profiles have been obtained for several different atomistic AFM tip profiles and compared to those obtained from molecular dynamics simulations presented in the literature [1].

Characterisation of Plasticity Response for Reciprocating Sliding Wear Test of Ti-6Al-4V under Variables Normal Load

2015 ◽  
Vol 1087 ◽  
pp. 350-354 ◽  
Author(s):  
D. Harun ◽  
Abdul Latif Mohd Tobi ◽  
A. Singh Chaal ◽  
Ramdziah Md. Nasir
Keyword(s):  
Plastic Deformation ◽  
Sliding Wear ◽  
Wear Track ◽  
Normal Load ◽  
Surface Profile ◽  
Wear Test ◽  
Wear Scar ◽  
Reciprocating Sliding ◽  
Applied Normal Load ◽  
Reciprocating Sliding Wear

Reciprocating sliding wear test of uncoated titanium alloy, Ti-6Al-4V is investigated using pin-on-flat arrangement under variable applied normal load. The wear scar produced by the reciprocating sliding wear test is analysed by surface profile examination using 2D and 3D optical microscope (OM) and Scanning Electron Microscope (SEM). Through SEM, the energy-dispersive X-ray spectroscopy (EDX) is used to characterise the composition of the substance on the worn surface. The hardness value of the wear scar is investigated at three regions which are; worn, unworn and the end of the wear track using Micro Vickers Hardness Test. The presence of moderate oxygen composition and the increasing in hardness value at the end of wear track suggesting evidence of plastic deformation. The increase in hardness value at the end of wear track indicates increase in plastic deformation with increasing applied normal load.

A Unified Treatment of Axisymmetric Adhesive Contact on a Power-Law Graded Elastic Half-Space

2013 ◽  
Vol 80 (6) ◽  
Author(s):  
Fan Jin ◽  
Xu Guo ◽  
Wei Zhang
Keyword(s):  
Half Space ◽  
Power Law ◽  
Contact Region ◽  
Adhesive Contact ◽  
Elastic Half Space ◽  
Hertzian Contact ◽  
Contact Radius ◽  
Abel Transformation ◽  
Numerical Solution Methods ◽  
Special Cases

In the present paper, axisymmetric frictionless adhesive contact between a rigid punch and a power-law graded elastic half-space is analytically investigated with use of Betti's reciprocity theorem and the generalized Abel transformation, a set of general closed-form solutions are derived to the Hertzian contact and Johnson–Kendall–Roberts (JKR)-type adhesive contact problems for an arbitrary punch profile within a circular contact region. These solutions provide analytical expressions of the surface stress, deformation fields, and equilibrium relations among the applied load, indentation depth, and contact radius. Based on these results, we then examine the combined effects of material inhomogeneities and punch surface morphologies on the adhesion behaviors of the considered contact system. The analytical results obtained in this paper include the corresponding solutions for homogeneous isotropic materials and the Gibson soil as special cases and, therefore, can also serve as the benchmarks for checking the validity of the numerical solution methods.

Adhesive Contact of Bodies Having an Elliptical Contact Area

2005 ◽  
Author(s):  
K. L. Johnson ◽  
J. A. Greenwood
Keyword(s):  
Closed Form ◽  
Contact Area ◽  
Adhesive Contact ◽  
Contact Radius ◽  
General Shape ◽  
Elliptical Contact ◽  
Jkr Theory ◽  
Two Bodies

The so-called JKR theory of adhesion between elastic spheres in contact (Johnson, Kendall & Roberts 1971, Sperling 1964) has been widely used in micro-tribology. In this paper the theory is extended to solids of general shape and curvature. It is assumed that the area of contact is elliptical which turns out to be approximately true, though the eccentricity is different from that for non-adhesive contact. Closed form expressions are found for the variation with load of contact radius and displacement, as a function of the ratio of principal relative curvatures of the two bodies in contact. The pull-off force is found to decrease with increasing eccentricity from its value of 3πΔγR/2 in the case of contact of spheres of radius R.

Sign in / Sign up

Export Citation Format

Share Document