The role of contact pressure on skin friction has been documented in multiple experimental studies. Skin friction significantly raises in the low-pressure regime as load increases while, after a critical pressure value is reached, the coefficient of friction of skin against an external surface becomes mostly insensitive to contact pressure. However, up to now, no study has elucidated the qualit...

An inelastic bouncing ball driven by an oscillating plate is modelled in MatLab and then experimentally investigated in the laboratory. Experimental results qualitatively match the computational model, demonstrating bifurcation and chaos. Discrepancies of the physical system are clearly traced, including friction, elasticity, and feedback, but only friction is accounted for in the model. Furthe...

The stretching response of a single collapsed homopolymer is studied using Brownian dynamic simulations. The irreversibly dissipated work is found to be dominated by internal friction effects below the collapse temperature, and the internal viscosity grows exponentially with the effective cohesive strength between monomers. These results explain friction effects of globular DNA and are relevant...

Cold rolling of steel is one of the most important metal forming processes so an accurate control of its parameters during the process is necessary. In this paper, the friction coefficient has been proposed as a function of cold rolling parameters such as forward slip, forward and backward tensile stresses ,strip thickness, static deformation, resistance of strip before and after rolling ,strip...

the objectives in the cold rolling process include improved sheet surface quality, enhanced steel mechanical strength, and better solidification operations. given the increasing demand for higher steel surface quality, more rapid production, and thinner steel plates, more attention has been directed toward the parameter of temperature in cold rolling as a means of achieving the above objectives...

The welding of materials by applying Friction Stir Welding technique is a new solid-state joining technique. The main advantage of this method compared to the traditional joining process is that it minimizes problem-related to metal resolidification as the method incorporates no melting phase. In this experimental work, the effect of friction stir welding (FSW) technique on the microstructu...

Dielectric fluctuations underlie a wide variety of physical phenomena, from ion mobility in electrolyte solutions and decoherence in quantum systems to dynamics in glass-forming materials and conformational changes in proteins. Here we show that dielectric fluctuations also lead to noncontact friction. Using high sensitivity, custom fabricated, single crystal silicon cantilevers we measure ener...

In the metal forming process, a realistic frictional coefficient must be specified at the die/work piece interface. Several methods are developed to evaluate friction coefficient in large deformation processes. This paper presents the concept of friction calibration map to determine different frictional conditions between interfaces of die and billet in the upsetting process. One such map is ge...

We show that the correlated stochastic fluctuation of the friction coefficient can give rise to long-range directional motion of a particle undergoing Brownian random walk in a constant periodic energy potential landscape. The occurrence of this motion requires the presence of two additional independent bodies interacting with the particle via friction and via the energy potential, respectively...

In this work polyhedron-like gold and sphere-like silver nanoparticles (NPs) were manipulated on an oxidized Si substrate to study the dependence of the static friction and the contact area on the particle geometry. Measurements were performed inside a scanning electron microscope (SEM) that was equipped with a high-precision XYZ-nanomanipulator. To register the occurring forces a quartz tuning...