scholarly journals A Tribometric Device for the Rolling Contact of Soft Elastomers

2021 ◽  
Author(s):  
Brodie Hoyer ◽  
Rong Long ◽  
Mark E. Rentschler
Keyword(s):  
Contact Mechanics ◽  
Fundamental Problem ◽  
Finite Thickness ◽  
Medical Robotics ◽  
Adhesive Contact ◽  
Rolling Contact ◽  
Experimental Investigations ◽  
Pdms Substrate ◽  
Textured Surfaces ◽  
Tribometric Device

Abstract Rolling contact experimentation is a viable and instructive method for exploring the adhesive contact between surfaces. When applied to soft elastomeric or engineered surfaces, the results of such experiments can provide insights relevant to medical robotics, soft gripping applications, and reversible dry adhesives for bandages or wearable devices. We have designed and built a tribometric device to capture normal and tangential forces between a rolling indenter and substrate correlated with contact area imaging. The device was validated using an experimental setup involving a rigid, nominally smooth acrylic cylinder rolling against a flat polydimethylsiloxame (PDMS) substrate, the results of which matched favorably with accepted contact mechanics theories. The second test involved an indenter with a rigid core and thin (3 mm) smooth shell of a highly deformable, viscoelastic polyvinyl chloride (PVC) rolling on the same PDMS substrate. This test deviated significantly from analytical predictions, highlighting the effects of finite-thickness effects, viscoelasticity, and interfacial slip. This device will facilitate experimental investigations of the rolling contact mechanics between textured surfaces and soft tissue-like materials, which is an important fundamental problem in medical robotics.

scholarly journals The Indentation Rolling Resistance in Belt Conveyors: A Model for the Viscoelastic Friction

Lubricants ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 58 ◽  
Author(s):  
Nicola Menga ◽  
Francesco Bottiglione ◽  
Giuseppe Carbone
Keyword(s):  
Contact Problem ◽  
Finite Thickness ◽  
Numerical Procedure ◽  
Contact Problems ◽  
Accurate Solution ◽  
Rolling Contact ◽  
Viscoelastic Layer ◽  
Force Coefficient ◽  
Belt Conveyors ◽  
Energy Dissipated

In this paper, we study the steady-state rolling contact of a linear viscoelastic layer of finite thickness and a rigid indenter made of a periodic array of equally spaced rigid cylinders. The viscoelastic contact model is derived by means of Green’s function approach, which allows solving the contact problem with the sliding velocity as a control parameter. The contact problem is solved by means of an accurate numerical procedure developed for general two-dimensional contact geometries. The effect of geometrical quantities (layer thickness, cylinders radii, and cylinders spacing), material properties (viscoelastic moduli, relaxation time) and operative conditions (load, velocity) are all investigated. Physical quantities typical of contact problems (contact areas, deformed profiles, etc.) are calculated and discussed. Special emphasis is dedicated to the viscoelastic friction force coefficient and to the energy dissipated per unit time. The discussion is focused on the role played by the deformation localized at the contact spots and the one in the bulk of the thin layer, due to layer bending. The model is proposed as an accurate solution for engineering applications such as belt conveyors, in which the energy dissipated on the rolling contact of idle rollers can, in some cases, be by far the most important contribution to their energy consumption.

Numerical Method of Analyzing Contact Mechanics between a Sphere and a Flat Considering Lennard-Jones Surface Forces of Contacting Asperities and Noncontacting Rough Surfaces

2012 ◽  
Vol 134 (1) ◽  
Author(s):  
Kyosuke Ono
Keyword(s):  
Numerical Method ◽  
Contact Mechanics ◽  
Rough Surfaces ◽  
Present Theory ◽  
Adhesive Contact ◽  
Adhesive Force ◽  
Surface Forces ◽  
Contact Theory ◽  
Magnetic Disk ◽  
Lennard Jones

A new numerical method of analyzing adhesive contact mechanics between a sphere and a flat with sub-nanometer roughness is presented. In contrast to conventional theories, the elastic deformations of mean height surfaces and contacting asperities, and Lennard-Jones (LJ) surface forces of both the contacting asperities and noncontacting rough surfaces including valley areas are taken into account. Calculated contact characteristics of a 2-mm-radius glass slider contacting a magnetic disk with a relatively rough surface and a 30-mm-radius head slider contacting a currently available magnetic disk with lower roughness are shown in comparison with conventional adhesive contact theories. The present theory was found to give a larger adhesive force than the conventional theories and to converge to a smooth sphere-flat contact theory as the roughness height approaches zero.

scholarly journals On the influence of conformity on wheel–rail rolling contact mechanics

2016 ◽  
Vol 103 ◽  
pp. 647-667 ◽  
Author(s):  
Julio Blanco-Lorenzo ◽  
Javier Santamaria ◽  
Ernesto G. Vadillo ◽  
Nekane Correa
Keyword(s):  
Contact Mechanics ◽  
Rolling Contact

Experimental Investigations Upon Fatigue Life of Circular Contacts With Transversal Furrow

2005 ◽  
Author(s):  
Delia F. Cerlinca ◽  
Emanuel N. Diaconescu
Keyword(s):  
Fatigue Life ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Fatigue Tests ◽  
Geometric Parameters ◽  
Rolling Contact ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Contact Fatigue Life

Rolling contact fatigue depends essentially on both surface and subsurface populations of defects. First, this paper describes experimental results obtained in rolling contact fatigue tests in the presence of a furrow oriented transversally to the race-way. Then an attempt to predict theoretically the effect of geometric parameters of the furrow upon contact fatigue life is described.

Friction Reduction by Micro-Textured Surfaces in Lubrication

2018 ◽  
Vol 12 (4) ◽  
pp. 603-610 ◽  
Author(s):  
Yue Sun ◽  
Keita Shimada ◽  
Shaolin Xu ◽  
Masayoshi Mizutani ◽  
Tsunemoto Kuriyagawa ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Contact Surface ◽  
Friction Reduction ◽  
Experimental Investigations ◽  
Textured Surface ◽  
Textured Surfaces ◽  
Diamond Cutting ◽  
Tribological Tests ◽  
Sliding Direction

Experimental investigations were carried out to verify if the friction reduction in lubrication can be expanded by a textured surface with sawtooth riblets. Sawtooth riblets were formed by ultraprecision diamond cutting, with a ridge angle of about 60°–90° and height of about 20–50 μm on the contact surface. Six types of textured surfaces with different ridge angles, heights, and sliding directions were tested and compared with the untextured surface. The tribological tests were conducted by a flat-on-flat tribometer in lubrication. The effects of the ridge angle, height, and relative sliding direction on the friction coefficient in lubrication were reported.

Tribology in Full View

MRS Bulletin ◽  
2008 ◽  
Vol 33 (12) ◽  
pp. 1168-1173 ◽  
Author(s):  
Laurence D. Marks ◽  
Oden L. Warren ◽  
Andrew M. Minor ◽  
Arno P. Merkle
Keyword(s):  
Contact Mechanics ◽  
Mechanical Stability ◽  
Fundamental Problem ◽  
Interface Problem ◽  
The Novel ◽  
Sensors And Actuators ◽  
Force Sensitivity ◽  
Transmission Electron ◽  
New Information

AbstractFor many years, a fundamental problem in contact mechanics, both tribology and indentation problems, has been the inability to see what is taking place—the buried-interface problem. Over the past few years, there have been developments whereby it has become possible to perform contact mechanics experimentsin situwithin a transmission electron microscope. These new experiments have been enabled by both the miniaturization of sensors and actuators and improvements in their mechanical stability and force sensitivity. New information is now becoming available about the nanoscale processes of sliding, wear, and tribochemical reactions, as well as microstructural evolution during nanoindentation such as dislocation bursts and phase transformations. This article provides an overview of some of these developments, in terms of both the advances in technical instrumentation and some of the novel scientific insights.

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