-A novel dynamic friction experiment using the Kolsky bar concept was developed. The technique is complementary to the plate impact and other macroscopic friction experiments in the sense that sliding velocities and pressures not attainable otherwise can be investigated. The experimental results reported in this article show that the technique provides accurate and repeatable measurement of tim...

Knowledge requires both freedom and friction. Freedom to set up our epistemic goals, choose the subject matter of our investigations, espouse cognitive norms, design research programs, etc., and friction (constraint) coming from two directions: the object or target of our investigation, i.e., the world in a broad sense, and our mind as the sum total of constraints involving the knower. My goal ...

This work concerns the modelling and experimental verification of the highly nonlinear friction behavior in positioning on the nanometer scale. The main goal of this work is to adjust and identify a simple dynamic friction model which allows a model-based estimation of the friction force in combination with the system inertia against displacement. Experiments in the pre-sliding and sliding fric...

This article describes the design of a new test rig for measuring the friction force in pneumatic components and seals. The test rig was designed in order to measure both the overall friction force in a pneumatic cylinder or a valve as a whole, and the single contribution to friction force caused by the sliding seals. To this end, special fixtures and devices were designed and manufactured in o...

In many sliding systems consisting of solid object on a solid substrate under dry condition, the friction force does not depend on the apparent contact area and is proportional to the loading force. This behaviour is called Amontons' law and indicates that the friction coefficient, or the ratio of the friction force to the loading force, is constant. Here, however, using numerical and analytica...

A shallow-layer model for granular flows down inclines is completed with a closure relation for the macroscopic bed friction obtained from micro-scale, discrete particle simulations of steady flows over geometrically rough bases with contact friction. Microscopic friction can be different between bulk particles and with particles at the base, where the latter is systematically varied. When exte...

In this investigation three effects are included in a recently developed scale-dependent multi-asperity model of elastic contact and friction. First, a Weibull distribution of asperity heights is used, which allows the skew and kurtosis to be varied, but not independently of each other. Second, the effect of non-constant radii of curvature of the asperity summits, with the curvature varying wit...

We have characterized the frictional properties of nanostructured carbon films grown by supersonic cluster beam deposition via an atomic force-friction force microscope (AFM-FFM). The experimental data are discussed on the basis of a modified Amonton's law for friction, stating a linear dependence of friction on load plus an adhesive offset accounting for a finite friction force in the limit of...

The purpose of this work was to join and assess the development of solid state joints of dissimilar material AA6082 aluminum alloy and AISI 304 stainless steel, via continuous drive friction welding process, which combines the heat generated from friction between two surfaces and plastic deformation. Tests were conducted with different welding process parameters. The results were analyzed by me...

ribology is the science and technology of contacting solid surfaces in relative motion, including the study of lubricants, lubrication, friction, wear, and bearings. It is estimated that friction and wear cost the U.S. economy 6% of the gross national product [1]. For example, 5% of the total energy generated in an automobile engine is lost to frictional resistance. The study of nanoscale frict...