The static friction coefficient between two materials is considered to be a material constant. We present experiments demonstrating that the ratio of shear to normal force needed to move contacting bodies can, instead, vary systematically with controllable changes in the external loading configuration. Large variations in both the friction coefficient and consequent stress drop are tightly link...

This paper deals with the full discretization of quasistatic 3D Signorini problems with local Coulomb friction and a coefficient of friction which may depend on the solution. After a time discretization we obtain a system of static contact problems with Coulomb friction. Each of these problems is solved by the T-FETI domain decomposition method used in auxiliary contact problems with Tresca fri...

in this study, geometrical, gravimetrical and frictional properties of four common varieties of iranian canola seeds (namely: slm, hyola, okapi, orient), containing the mean moisture value of 6.5% (w.b.) were investigated. geometrical and gravimetrical properties included length, diameter, geometric mean diameter, sphericity, thousand seed mass, volume, true density, bulk density and porosity. ...

We study static packings of frictionless and frictional spheres in three dimensions, obtained via molecular dynamics simulations, in which we vary particle hardness, friction coefficient, and coefficient of restitution. Although frictionless packings of hard spheres are always isostatic (with six contacts) regardless of construction history and restitution coefficient, frictional packings achie...

Article history: Received 6 October, 2015 Accepted 7 March 2016 Available online 8 March 2016 Dry friction depends on the surface topography which, in turn, is governed by machining parameters in addition to several other factors,. Therefore, in order to establish a qualitative relationship among these factors, the surface roughness and coefficient of static friction are measured for specimens ...

A new dynamic friction force model for the longitudinal road/tire interaction for wheeled ground vehicles is validated via experiments with an actual passenger vehicle. Contrary to common static friction/slip maps, this new dynamic friction model is able to accurately capture the transient behavior of the friction force observed during transitions between braking and acceleration. A velocitydep...

A new generation of experiments on dry macroscopic friction has revealed that the transition from static to dynamic friction is essentially a spatially and temporally non-uniform process, initiated by a rupture-like detachment front. We show the suitability of the FrenkelKontorova model for describing this transition. The model predicts the existence of two types of detachment fronts, explainin...

In rehabilitation training, high-fidelity simulation environments are needed for reproducing the effects of slippery surfaces, in which potential balance failure conditions can be reproduced on demand. Motivated by these requirements, this article considers the design of variable-friction devices for use in the context of human walking on surfaces in which the coefficient of friction can be con...