We introduce a simple model to describe the frictional properties of granular media under shear. We model the friction force in terms of the horizontal velocity ẋ and the vertical position z of the slider, interpreting z as a constitutive variable characterizing the contact. Dilatancy is shown to play an essential role in the dynamics, inducing a stick-slip instability at low velocity. We compu...

This paper presents frictional characteristics of thrust bearing in scroll compressor. The coefficient of friction in thrust bearing was measured by both elemental friction test and loss classification based on the performance test of actual scroll compressor, and investigated frictional characteristics focusing on the behavior of sliding portion which affects the generation of oil film by expe...

The surface topography of the human wrist skin is studied by using optical and atomic force microscopy (AFM) methods. By using these techniques the surface roughness power spectrum is obtained. The Persson contact mechanics theory is used to calculate the contact area for different magnifications, for the dry and wet skin. The measured friction coefficient between a glass ball and dry and wet s...

When a compliant sheet of material is dragged over a curved surface of a body, the frictional forces generated can be many times greater than they would be for a planar interface. This phenomenon is known to contribute to the abrasion damage to skin often suffered by wearers of incontinence pads and bed/chairbound people susceptible to pressure sores. Experiments that attempt to quantify these ...

This paper presents a mixed variational framework and numerical examples to treat a bidimensional friction contact problem in large deformation. Two different contact algorithms with friction are developed using the 2D finite element code PLAST2. The first contact algorithm is the classical node-on-segment, and the second one corresponds to an extension of the mortar element method to a unilate...

The thermal state of a frictional contact with varying normal loads and sliding speeds friction pair after plasma electrolytic processing is considered. It shown that an increase in the temperature decreases coefficient friction, wear rate tribointerface increases contact.

Dundurs [Properties of elastic bodies in contact. In: de Pater AD, Kalker JJ, editors. The mechanics of the contact between deformable bodies. Delft: Delft University Press; 1975. p. 54–66] has shown that if the contact area in a frictionless elastic system under load is equal to or smaller than that before loading (i.e. the contact is receding), the extent of the contact area is load-independe...

We are interested in the finite element approximation of Coulomb’s frictional unilateral contact problem in linear elasticity. Using a mixed finite element method and an appropriate regularization, it becomes possible to prove existence and uniqueness when the friction coefficient is less than Cε| log(h)|−1, where h and ε denote the discretization and regularization parameters, respectively. Th...

Using a MEMS-based sensing device, we have measured the normal and tangential stress fields at the base of a rough elastomer layer in contact with a smooth glass cylinder in steady sliding. This geometry allows for a direct comparison between the stress profiles measured along the sliding direction and the predictions of an original exact bidimensional model of friction. The latter assumes Amon...

In this paper we consider an abstract class of time-dependent quasi variational–hemivariational inequalities which involves history-dependent operators and a set unilateral constraints. First, establish the existence uniqueness solution by using recent result for elliptic in reflexive Banach spaces combined with fixed-point principle operators. Then, apply to show unique weak solvability quasis...