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Petrus van Musschenbroek was a famous scientist and inventor, natural philosopher, experimental physicist, engineer, instrument builder, experimenter, in the continental Newtonian tradition of Boerhaave and ‘s Gravesande. And: a tribologist. He is one who deserves more fame than he has received so far, and which is well documented in this publication. Van Musschenbroek coined the name tribometer for his device to measure friction in a journal bearing, and some authors rightly refer to this. However, what seems to have remained unnoticed until now is that he also published quantitative results of his friction measurements and tried to arrive at general laws of friction based on them. He reported in detail on friction experiments on sliding, dry as well as lubricated, sliders and journal bearings, a novum in his time, as early as in 1734. When the data from Van Musschenbroek's tables are mapped into graphs, a method which was not in use at that time, two Stribeck curves for journal bearings emerge. Van Musschenbroek's work deserves much more acclaim in the tribology community than it has now.

The handling of sticky raw material can cause problems during operation of process equipment in the cement production industry. These handling problems are generally observed when raw material (e.g. wet clay) sticks to machine walls and causes blockage of outlets. This leads to frequent production shutdowns and expensive cleaning operations. In this work, the effects of surface material and process parameters on the friction forces between wet clay and surface were investigated. Various surface materials and clay impact speeds were investigated.The results demonstrate that not only the equipment surface material but also the surface roughness influences the observed frictional behavior. The ranking of the materials in terms of effective static friction coefficients fell in two groups with equal performance within the group: 1) Two Teflon-based coatings (Accofal 2G54 and Accolan LB), polished AISI 304 stainless steel, Matrox lining, and a polyurethane-based coating (best performing surfaces), 2) Mild steel, a silicone-based coating, and AISI 304 stainless steel (worst performing surfaces). However, the friction coefficients of the two groups only varied by a factor of two, suggesting that adhesion of wet clay to surfaces is difficult to avoid by the use of coatings.

Pilots need accurate predictions on the quality of runway surface conditions when operating on snow/ice contaminated runways. These predictions are typically made by friction measurements, or by expert judgments of runway inspectors. This study presents a decision support model (the IRIS runway model) for runway inspectors that interprets descriptive data from SNOWTAM reports and predicts the braking action on the common scale from 1 to 5, ranging from “poor” to “good”. The model is tested on two airports in Norway during the winter seasons 2008/2009 to 2010/2011. Two other predictors of the braking action (assessments by runway inspectors and friction measurements) were also included. Analyses of 1261 friction-limited landings of commercial airplanes were used to compare predicted and measured braking actions. The IRIS runway model was found to be more conservative than the assessments of Norwegian runway inspectors, and even more conservative than friction measurements. In 86% of the landings, the IRIS runway model predicted the conditions within ± 1 category of what the airplanes experienced, compared to 77% achieved by the runway inspectors. The predictions by the friction measurement devices were the least conservative and predicted the conditions within ± 1 category in 61% of the landings. The model is now implemented in 15 airports in Norway.

Tactile perception of materials and surface texture involves friction under light normal loads and is fundamental to further advancing areas such as tactile sensing, haptic systems used in robotic gripping of sensitive objects, and characterization of products that range from fabrics to personal care products, such as lotions, on skin. This paper describes a new apparatus to measure friction simultaneously with dynamic quantities such as accelerations, forces, and sound pressures resulting from light sliding contact over a soft material, much like a finger lightly touching a soft material. The paper also introduces a novel friction and adhesion measurement method that can be particularly useful for soft materials and light normal loads. (C) 2011 Elsevier B.V. All rights reserved.

A methodology for the prediction of the press-fit curve in the assembly of a railway axle and wheel is described. It starts from friction measurements on samples taken directly from the two components. A new apparatus, adaptable to a common axial testing machine, was developed for this aim: it permits the contact pressure and sliding speed to be varied in order to change the lubrication condition of the contact surfaces. Two calculation models are then proposed to predict the press-fit curves. They take the results of the friction measurements as input data, together with the wheelset geometry, the design interference and the material characteristics. The first one is a finite element method (FEM) model, which is very accurate but difficult to use, which also allows the effect of the wheel seat chamfer and the oil injection grove to be assessed. The second one is a simplified analytical model based on the theory of axisymmetric bodies, which works on an approximate wheel geometry; nevertheless, it gives results in good agreement with those of the FEM model and with the experimental press-fit curves of the examined wheelsets. Moreover, the simplified model is very fast and easy to use, thus constituting a powerful and useful tool for the design of new wheelsets.

In centreless through feed grinding the quality of the ground parts is influenced by several process variables. Some of these process parameters alter the frictional conditions at the control wheel-workpiece and the grinding wheel-workpiece interfaces which, in turn, influence the axial feed rate and rate of rotation of the workpiece. In addition, the type of cutting fluid plays an important role in determining the friction at the control wheelworkpiece interface. In this paper, an attempt is made to describe the influence of some of the process parameters on the slip in the axial movement and the change in the rate of rotation of the workpiece. Also the influence of different cutting fluids, which alters the nature of the frictional contact at the control wheel-workpiece interface, on the workpiece movements and quality of the ground parts is described. The experimental work carried out, in connection with this, is included. Further, from the analysis of the experimental results some useful conclusions have been derived which would be helpful in improving the performance of the process.