Frictional forces arise whenever objects around us are set in motion. Controlling them in a rational manner means gaining leverage over mechanical energy losses and wear. This paper presents a way of manipulating nanoscale friction by means of in situ lubrication and interfacial electrochemistry. Water lubricant is directionally condensed from the vapor phase at a moving metal-ionic crystal int...

Friction has an important influence in metal forming operations as it contributes to the success or failure of the process. In the present investigation, the effect of friction on metal forming was studied by conducting compression tests of cylindrical Al-Mg alloy using Finite Element Method (FEM) technique. Three kinds of compression tests were performed. For the first test, a constant coeffic...

In this paper, an analytical method based on Modified Slab Method of analysis is presented to study the asymmetrical rolling process due to difference in work rolls radii, rolls speeds and interface frictions. The shear force imposed on material along the contact region is considered to be a function of the frictional factor and the roll gap geometry. Elastic-plastic with linear work hardening ...

Diamond and diamondlike carbon (DLC) films exhibit a wide range of sometimes contradictory tribological behavior. Experimentally, isolating the influences of factors such as film structure, testing conditions, and environmental effects has proven difficult. In this work, molecular dynamics simulations were used to examine the effects of film structure, passivation, adhesion, tribochemistry, and...

This paper describes a preliminary work devoted to the design of a control architecture for a defective haptic interface, i.e. an underactuated haptic interface not able to apply forces along arbitrary directions. This interface is intended to be used for grasping tasks, where unilateral constraints are usually present. The main control problems considered in this paper concern the study of fri...

Lubrication on sharp curves has been commonly adopted as a method of reducing friction between the wheel flange and rail gauge face to minimize wear and energy consumption. Additionally, lubrication between the running surface of the low-rail and the wheel tread has recently been recognized as a significant factor in reducing the likelihood of low-rail corrugation, squealing noise and rail gaug...

A friction display system is proposed for virtual environments. Since a user’s fingertip is often placed inside a ring or thimble of a haptic interface , the finger pad cannot move relative to the finger structure as freely as it would move in the real world. Thus, it is necessary to imitate the real world movement of the human finger pad in the virtual environment. This paper quantifies the fr...

We investigate the evolution of heterogeneous stress states along frictional interfaces. Using finite-element simulations, we model the occurrence of precursory slip sequences on a deformable-deformable as well as a deformable–rigid interface between two solids. Every interface rupture creates a stress concentration at its arrest position and erases the stress concentrations produced by previou...

Discussions of energy dissipation during friction processes have captured the attention of engineers and scientists for over 300 years. Why then do we know so little about either dissipation or friction processes? A simple answer is that we cannot see what is taking place at the interface during sliding. Recently, however, devices such as the atomic force microscope have been used to perform fr...

In this paper, an analytical method based on Modified Slab Method of analysis is presented to study the asymmetrical rolling process due to difference in work rolls radii, rolls speeds and interface frictions. The shear force imposed on material along the contact region is considered to be a function of the frictional factor and the roll gap geometry. Elastic-plastic with linear work hardening ...