We report a direct measurement of the friction coefficient of a fluctuating (and slipping) contact line using a thin vertical glass fiber of diameter d with one end glued onto a cantilever beam and the other end touching a liquid-air interface. By measuring the broadening of the resonant peak of the cantilever system with varying liquid viscosity η, we find the friction coefficient of the conta...

The buckling behavior of rod strings in wellbore is one of the key issues in petroleum engineering. The slender rod strings in vertical wellbore were selected as research objects. Based on the energy method, the critical load formulas of sinusoidal and helical buckling were derived for the string with the bottom of the wellbore pressure. According to the sinusoidal and helical buckling’s geomet...

In the Structural Dynamics and Acoustics group at the University of Twente, we aim to develop a quantitative tyre/road noise model. An essential part of this model is an accurate contact algorithm which is fast enough to simulate tyre vibrations up to the acoustic frequencies. In this paper we present a contact algorithm, describing the contact between a tyre and a road surface, which has the p...

The early stage sliding contact fatigue behavior of nanocrystalline materials, with average and total range of grain sizes well below 100 nm, was studied. The evolution of friction and damage during repeated sliding contact in the nanocrystalline metals and alloys was systematically compared and contrasted with that in ultrafine-crystalline and microcrystalline materials so as to develop a broa...

We propose a simple adaptation to the Tresca friction case of the Nitsche-based finite element method given in [Chouly-Hild, 2012, Chouly-Hild-Renard, 2013 ] for frictionless unilateral contact. Both cases of unilateral and bilateral contact with friction are taken into account, with emphasis on frictional unilateral contact for the numerical analysis. We manage to prove theoretically the fully...

Large-scale molecular-dynamics simulations are performed to study friction in nanoscale single asperity contacts. The modeling system consists of a tip made of H-terminated diamond-like carbon and an H-terminated diamond sample. Simulations are carried out using a reactive bond-order interatomic potential integrated with dispersive interactions. A quantitative agreement in contact pressures and...

The friction and wear phenomena appear due to contact and relative motion between two solids. The evolution of contact conditions depends on loading conditions and mechanical behaviours. The wear phenomena are essentially characterized by a matter loss. Wear and friction are in interaction due to the fact that particles are detached from the solids. A complex medium appears as an interface havi...

Sliding friction across a thin soft lubricant film typically occurs by stick-slip, the lubricant fully solidifying at stick, yielding and flowing at slip. The static friction force per unit area preceding slip is known from molecular dynamics (MD) simulations to decrease with increasing contact area. That makes the large-size fate of stick-slip unclear and unknown; its possible vanishing is imp...

We develop a simplified model to predict the frictional behaviour of the contact between the surfaces of a rotary shouldered thread connection in the make-up process of premium tubular connections as used in the oil pipeline business. A classic wear model is applied at the scale of the surface asperities to predict the evolution of friction between initially shot-peened surface and bronze plate...

In this paper, we present an analytical method to investigate the behavior of a two degrees of freedom oscillator excited by dry friction. The system consists of two masses connected by linear springs. These two masses are in contact with a driving belt moving at a constant velocity. The contact forces between the masses and the belt are obtained from Coulomb’s friction laws. A set of periodic ...