One of the great enemies of rubber compounds is heat. Heat will cause chemical and physical degradation of vulcanized rubber as well as a considerable loss in its strength. A major source of heat generation in a tire is due to internal friction resulting from the viscoelastic deformation of the tire as it rolls along the road. Another source of heat generation in a tire is due to its contact fr...

We use atomic force microscopy (AFM) to determine the frictional properties of nanoscale single-asperity contacts involving octadecyltrichlorosilane (OTS) monolayers and silicon. Quantitative AFM measurements in the wearless regime are performed using both uncoated and OTS-coated silicon AFM tips in contact with both uncoated and OTS-coated silicon surfaces, providing four pairs of either self-...

Grandin, M. 2017. Tribology of Metal-Graphite Composites. A Study of Sliding Electrical Contact Surfaces. Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 1565. 75 pp. Uppsala: Acta Universitatis Upsaliensis. ISBN 978-91-513-0079-5. An environmentally sustainable production of electrical power is important for preserving the earth’s natural res...

Surface modification techniques have been developed significantly in the last couple of decades for enhanced tribological performance of artificial hip implants. Surface modification techniques improve biological, chemical and mechanical properties of implant surfaces. Some of the most effective techniques, namely surface texturing, surface coating, and surface grafting, are applied to reduce t...

Contact between rubber-soled shoes and indoor sports surfaces commonly results in brief, high-pitched “squeaks” (Fig. 1). The classical Amontons-Coulomb friction paradigm assumed by most slip-resistance research does not accommodate vibration or sound generation. Consequently, an examination of this phenomenon offers the possibility of novel insights into the mechanics of shoe-surface interaction.

Local shape is an important attribute that can be sensed by exploratory movements of the finger. Normally this involves a blend of tactile and proprioceptive cues. A curved surface will deform the pad of a single finger and so tactile cues can indicate whether a surface is convex or concave or whether it slopes one way or another. When more subtle discriminations must be made between different ...

The friction coefficients between the hoisting-rope and pads made of different materials under environmental conditions, load sizes, frequencies were investigated by using a wear tester. variation law coefficient with change in working condition parameters was explored through orthogonal test analysis; it is found that dry friction, 100 N, frequency 1 Hz are optimal conditions to achieve an mat...

Fluorine polymers, commonly referred to as fluoropolymers, can greatly enhance the properties of coatings used in modern industrial, household and construction products. The qualities of fluoropolymer resins and oligomeric additives make them an ideal solution for applications requiring a high resistance to solvents, acids and bases, and most importantly an ability to significantly reduce frict...

Tribological behavior of Cu-MoS2 and Ag-MoS2 nanocomposite lubricant was studied. Cu nanoparticles produced by electrical explosion of copper wires and Ag nanoparticles prepared by electrospark erosion were employed as metal cladding modifiers of MoS2 nanolamellar particles. The tribological tests showed Cu-MoS2 and Ag-MoS2 nanocomposite lubricants changed the friction coefficient of the initia...

Power Assist Wheelchair (PAW) has being developed for users and caregivers in current high aging society. As a human-machine system, it is important for PAW to sense the human force and operation. In this paper, a Disturbance Observer (DOB) based force estimator is applied to PAW to estimate external forces including the human force, the rolling resistance and the sliding resistance. The rollin...