User login

Navigation

You are here

friction

WOM 2011 - 18th International Conference on Wear of Materials, Philadelphia, USA - Call for stand alone posters.

Submissions are now closed for oral presentations to WOM 2011, however, contributions are invited for stand-alone posters. WOM 2011 is to take place in Philadelphia, USA - April 3-7 next year.  It will focus on both the fundamental and applied aspects of wear and friction of materials at the macro-, micro- and nano-scale. Special emphasis will be placed on wear issues in harsh environments, energy conversion, and debris particle generation and its impact on the environment.

Chris W Smith's picture

PhD position available on Contact & Frictional Joints in Gas Turbines, fully funded

This studentship has now been filled, but there may be further similar studentships to follow.

 --------------------------------------

Frictional Coulomb model in Abaqus

Hello everybody,

I'm trying to add friction in my model.Now I have a body that is simply supported in a direction (vertical) and free to move in another one (horizontal). I want to use Coulomb friction in the horizontal direction in order to reduce displacements in that direction.

I read Abaqus User's Manual vol5 30.1.5 (frictional behavior) and I followed commands written there, but I think that works only with multiple bodies and not with a single body. I'm using Abaqus 6.7-1.

Could Someone help me?

Many many many thanks

Nicholas

How to define the contact state if the corresponding cohesive element is under compression (ABAQUS)

Hi. I am currently using cohesive element traction-separation law for modeling interface element between FRP and concrete. Can any one tell me how to define the contact state if the corresponding cohesive element is under compression in ABAQUS?   Yes, it's said that there won't be any damage if pure compression is applied to cohesive element, but my questions is how to consist of assuming that friction occurs on the damaged part as there is no friction definition in cohesive traction-separation law.   Please add comments if you know something about this. Thanks for help ^_^

azadpoor's picture

A recent paper about friction laws at the nanoscale

A very recent paper published a few minutes ago in Nature addresses the issue of friction laws at the nanoscale. Here is the abstract of the paper.Interested? here you can download the paper.

Nature 457, 1116-1119 (26 February 2009) | doi:10.1038/nature07748; Received 3 September 2008; Accepted 23 December 2008

Friction laws at the nanoscale

Yifei Mo1, Kevin T. Turner1,2,3 & Izabela Szlufarska1,3

Lucia Nicola's picture

PhD position at Delft University of Technology, NL

We welcome applications for a 4 year PhD positon in the field of computational mechanics and materials science. Further details in the attachment.

Ph.D position at EPFL-LSMS, Switzerland

Graduate assistantship positions are available in the Computational olid Mechanics Laboratory (http://lsms.epfl.ch/) at the Ecole olytechnique Fédérale de Lausanne (http://www.epfl.ch/).
We are interested in highly motivated Ph.D. candidates with an academic background (B.S. and M.S.) in either Mechanical Engineering, Civil ngineering or Computational Materials Science.

Mechanics-based nanotribology

Post-Doc Position is avalaible in Bio-Mimetic Adhesive Interfaces


A Post-Doc Position is avalaible in Bio-Mimetic Adhesive Interfaces (EbioAdI) at the University of Mons-Hanaut, Belgium

Supervisor: Prof. Pascal Damman, PhD
University of Mons-Hainaut
Interfaces & Complex Fluids Lab (InFluX)
European Collaborative Research Project (ESF-Eurocores)
Duration : 1 – 3 years
Deadline: 1 September 20088

In short:

Dean Eastbury's picture

Call for Papers: 17th IC Wear of Materials (WOM)

Authors are invited to submit, via the conference website, a 200-250 word abstract by 1 June 2008. The 17th International Conference on Wear of Materials (www.wom-conference.elsevier.com) will take place in Las Vegas, April 19-22, 2009. The conference will focus on both the fundamental and applied aspects of wear and friction of materials at the macro-, micro- and nano-scale.

vh's picture

Predictive modeling schemes for wear in tribometers

Choose a channel featured in the header of iMechanica: 

Study of wear in complex micro-mechanical components is often accomplished experimentally using a pin-
on-disc and twin-disc tribometer. The present paper proposes an approach that involves a computationally
efficient incremental implementation of Archard’s wear model on the global scale for modeling sliding and
slipping wear in such experiments. It will be shown that this fast simplistic numerical tool can be used to
identify the wear coefficient from pin-on-disc experimental data and also predict the wear depths within a

Liu's picture

Motion of precision linear bearings on nanometre scale

A systematic characterization of the motion and friction of a linear bearing with rolling elements used for nanopositioning reveals an explicit distinction of static and rolling friction. The effects

Xiaoyan Li's picture

Simulating Fullerene Ball Bearings of Ultra-low Friction

We report the direct molecular dynamics simulations for molecular ball bearings composed of fullerene molecules (C60 and C20) and multi-walled carbon nanotubes. The comparison of friction levels indicates that fullerene ball bearings have extremely low friction (with minimal frictional forces of  5.283×10-7 nN/atom and  6.768×10-7 nN/atom  for C60 and C20 bearings) and energy dissipation (lowest dissipation per cycle of  0.013 meV/atom  and  0.016 meV/atom  for C60 and C20 bearings). A single fullerene inside the ball bearings exhibits various motion statuses of mixed translation and rotation. The influences of the shaft's distortion on the long-ranged potential energy and normal force are discussed. The phonic dissipation mechanism leads to a non-monotonic function between the friction and the load rate for the molecular bearings.

Mike Ciavarella's picture

friction and plasticity: new avenues of research?

Choose a channel featured in the header of iMechanica: 

Based on some recent results by Anders Klabring, myself and Jim Barber, showing rigorously that Melan’s theorem only works for a very restricted class of frictional problems, we suggest possible ave

Mike Ciavarella's picture

review on KLJ's most loved areas in contact mechanics

Choose a channel featured in the header of iMechanica: 

If we read Ken Johnson’s Timoshenko medal 2006 speech also posted in iMechanica, the subjects Ken mentions in his brief and humorous speech are:-

  1. corrugation of railway rails,
  2. the damping at clamped joints,
  3. Hertz contact under the action of tangential friction forces,
  4. ‘tribology' (word invented by David Tabor along with F.P.Bowden in Cambridge),
  5. Atomic Force Microscope, Surface Force Apparatus & friction on the atomic scale,
  6. Relation between adhesion and friction.

These are probably the subjects Ken is most attached to. Some are older (but perhaps not solved, lke corrugation, for which the “short-pitch” fixed wavelength mechanism is still unclear despite Ken’s 40 years of efforts (!), and some are certainly fashionable today (like adhesion and friction at atomic scale). In starting this forum, why not start from here? Should we prepare a 1 page summary on each of these topics? Since I start this, I will do the effort on corrugation I promise in the next week or so!

Regards, Mike

Liu's picture

Positioning on nanometer scale: fighting friction

Most friction models for automatic control are targeted for the macro world, and are of questionable value for the motion control of the high precision positioing stages. We published a paper recently in Technishes Messen (TM) on a study of the friction behavior in the moving range of micrometers. It provides info for the development of friction models targeted for the motion control in high precision engineering.

The following is the abstract, and the full paper can be downloaded from http://www.atypon-link.com/OLD/doi/abs/10.1524/teme.2006.73.9.500

ABSTRACT Most friction models for automatic control are targeted for the macro world, and are of questionable value for the motion control of the nanopositioning and nanomeasuring machine (NPM) system. We present the frictional behaviour of some selected materials, coatings, lubricants, and bearings tested under running conditions similar to a NPM system. Continuous change of surface properties results in various friction characteristics, which substantiate the further development of tribological coatings, particularly for vacuum applications. We emphasize the system engineering approach in developing friction models, which combines fundamental knowledge of surface science, materials science, and its applications in design, construction and automatic control.

Pages

Subscribe to RSS - friction

More comments

Syndicate

Subscribe to Syndicate