Abstract The frictional cooperation of materials with different hardnesses occurs in machine elements one the following two variants: simple or reversed friction pairs. For a sliding pair, materials' deformation area (contact area) does not move over surface polymeric element during their interaction. In case pairs, contact changes its position as it moves polymer element. Tribological tests se...

We develop a numerical scheme to determine which planar snake motions are optimal for locomotory efficiency, across a wide range of frictional parameter space. For a large coefficient of transverse friction, we show that retrograde traveling waves are optimal. We give an asymptotic analysis showing that the optimal wave amplitude decays as the -1/4 power of the coefficient of transverse frictio...

In this study, the change at rubbing surfaces has been investigated experimentally using an acoustic emission signal monitoring system. A steel ring is slipped on the surface of  a metallic sheet to simulate frictional conditions. The mechanical disturbances caused by the movement of the ring produce stress waves propagating along the sheet surface. The out of plane displacement of the sheet su...

The aim of this study was to compare frictional resistance among conventional, passive and active selfligating brackets using Finite Elements Analysis (FEA). Seventynine (79) slide tests were performed by combining an upper first bicuspid conventional bracket, 0.018" stainless steel wires and 0.010" ligature by means of an INSTRON 3345 load system to obtain average maximum static frictional res...

The tribology of lubricated poly(ether ether ketone) (PEEK)—steel tribosystems was investigated in the static and boundary friction regime. Pentaerythrite ester and trimellitic acid ester were used as lubricants. The lubricants differed in their molecular structure but showed only minor differences in their rheological and cohesive energetic properties. In order to investigate the effect of the...

In this paper we correlate the Atomic Force Microscope probe movement with surface location while scanning in the imaging and Force versus distance modes. Static and dynamic stick-slip processes are described on a scale of nanometres to microns on a range of samples. We demonstrate the limits and range of the tip apex being fixed laterally in the force versus distance mode and static friction s...

A method of generating and measuring static small forces at the micro-Newton level is proposed. In the method, the down-slope component of gravity acting on a mass on an inclined plane is used as a static force. To realize a linear motion of the mass with a small friction, an aerostatic linear bearing is used. The forces acting on the mass, such as the down-slope component of gravity and the dy...

Over the past decade, many computational studies have explored the mechanics of normal indentation. Quantitative relationships have been well established between the load–displacement hysteresis response and material properties. By contrast, very few studies have investigated broad quantitative aspects of the effects of material properties, especially plastic deformation characteristics, on the...