Mechanics of adhesive contacts: experiment and theory

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in AIP Conference Proceedings 2167, 020201 (2019) and may be found at https://doi.org/10.1063/1.5132068.Adhesive contacts between steel indenters and a layer of soft transparent rubber have been studied experimentally and numerically. Experiments were carried out using a setup allowing for slow exact positioning of the indenter in both normal and tangential direction and observing the contact area with a camera placed under the rubber layer. Indentation of flat-ended cylindrical punches showed that Boundary Element simulations very accurately describe experimental results. Changing velocity allowed determining the importance of viscoelastic effects on the adhesive contact

Model of nanostructuring burnishing by a spherical indenter taking into consideration plastic deformations

A dynamic model of the nanostructuring burnishing of a surface of metallic details taking into consideration plastic deformations has been suggested. To describe the plasticity, the ideology of dimension reduction method supplemented with the plasticity criterion is used. The model considers the action of the normal burnishing force and the tangential friction force. The effect of the coefficient of friction and the periodical oscillation of the burnishing force on the burnishing kinetics are investigated

Impact of an elastic sphere with an elastic half space revisited: Numerical analysis based on the method of dimensionality reduction

An impact of an elastic sphere with an elastic half space under no-slip conditions (infinitely large coefficient of friction) is studied numerically using the method of dimensionality reduction. It is shown that the rebound velocity and angular velocity, written as proper dimensionless variables, are determined by a function of only the ratio of tangential and normal stiffness ("Mindlin-ratio"). The obtained numerical results can be approximated by a simple analytical expression

DYNAMICAL MODEL OF THE ASYMMETRIC ACTUATOR OF DIRECTIONAL MOTION BASED ON POWER-LAW GRADED MATERIALS

We consider an actuator whose driving bodies are made of Power-Law graded materials. The directional motion is generated by an asymmetric mechanism producing simultaneously vertical and horizontal oscillations of the indenter. The dynamic contact of gradient materials is described and the equation of motion for the drive is written down and analyzed. It is shown that the exponent of the elastic inhomogeneity significantly affects the average velocity of motion of the cargo, which can be dragged by the drive

Influence of tangential displacement on the adhesion strength of a contact between a parabolic profile and an elastic half-space

The adhesion strength of a contact between a rotationally symmetric indenter and an elastic half-space is analysed analytically and numerically using an extension of the method of dimensionality reduction for superimposed normal/tangential adhesive contacts. In particular, the dependence of the critical adhesion force on the simultaneously applied tangential force is obtained and the relevant dimensionless parameters of the problem are identified. The fracture criterion used coincides with that suggested by Johnson. In this paper, it is used to develop a method that is applicable straightforwardly to adhesive contacts of arbitrary bodies of revolution with compact contact area

Stick-slip boundary friction mode as a second-order phase transition with an inhomogeneous distribution of elastic stress in the contact area

This article presents an investigation of the dynamical contact between two atomically flat surfaces separated by an ultrathin lubricant film. Using a thermodynamic approach we describe the second-order phase transition between two structural states of the lubricant which leads to the stick–slip mode of boundary friction. An analytical description and numerical simulation with radial distributions of the order parameter, stress and strain were performed to investigate the spatial inhomogeneity. It is shown that in the case when the driving device is connected to the upper part of the friction block through an elastic spring, the frequency of the melting/solidification phase transitions increases with time

Influence of tangential displacement on the adhesion strength of a contact between a parabolic profile and an elastic half-space

The adhesion strength of a contact between a rotationally symmetric indenter and an elastic half-space is analysed analytically and numerically using an extension of the method of dimensionality reduction for superimposed normal/tangential adhesive contacts. In particular, the dependence of the critical adhesion force on the simultaneously applied tangential force is obtained and the relevant dimensionless parameters of the problem are identified. The fracture criterion used coincides with that suggested by Johnson. In this paper, it is used to develop a method that is applicable straightforwardly to adhesive contacts of arbitrary bodies of revolution with compact contact area

Boundary element method for nonadhesive and adhesive contacts of a coated elastic half-space

We present a new formulation of the boundary element method for simulating the nonadhesive and adhesive contac