I. Preliminary Remarks A. Introduction B. Some Fundamental Definitions and Questions C. Basic Scenarios for Friction D. Phenomenology of Static and Low-Velocity Kinetic Friction II. Rigid Walls A. Geometric Interlocking B. Thermal Effects C. Applications 1. Nanotubes 2. Curved, Nanoscale Contacts III. Dry, Elastic Friction A. Properties of the Prandtl–Tomlinson Model 1. Definition of the Model ...

The motion of an elastic body over a rough surface is simulated in one dimension using Newtonian dynamics. We drive the body by prescribing a constant velocity. We extract the friction force from the work done by the applied force in order to maintain the motion of the body. A positive amount of work is needed because energy is converted into the internal elastic degrees of freedom of the body....

A laboratory study was conducted to evaluate if two different age groups(young vs. old) had differences in walking velocity and heel contact velocity and, furthermore, if these gait characteristics could adversely influence initial friction demand characteristics(i.e. RCOF) and the likelihood of slip-initiation. Twenty eight(14 younger and 14 older adults) participated in the study. While weari...

Considering a kinematical velocity admissible field, the upper bound method has beenused for predicting the amount of pressure in hydroforming of sheet metals. The effects of workhardening, friction and blank size have been considered in pressure prediction. Also the effect ofsheet thickness variation has been considered in the present work formulations. The relation betweenpressure and punch s...

The resistance against rolling of a rigid cylinder on a at viscous surface is investigated. We found that the rolling-friction coeecient reveals strongly non-linear dependence on the cylinder's velocity. For low velocity the rolling-friction coeecient rises with velocity due to increasing deformation rate of the surface. For larger velocity, however, it decreases with velocity according to decr...

In this paper are presented the influences of the adhesion forces occurring in hyperbolic micro contact on the oil velocity and friction forces in hyper bolic micro bearing gap. Here are elaborated the dependences between adhesive forces and oil dynamic viscosity in super t hin boundary layer and in fluences of adhesive forces on the oil velocities and friction forces in microand nano-scale ari...

A new generation of experiments on dry macroscopic friction has revealed that the transition from static to dynamic friction is essentially a spatially and temporally non-uniform process, initiated by a rupture-like detachment front. We show the suitability of the FrenkelKontorova model for describing this transition. The model predicts the existence of two types of detachment fronts, explainin...

Time-stepping methods using impulse-velocity approaches are guaranteed to have a solution for any friction coefficient, but they may have nonconvex solution sets. We present an example of a configuration with a nonconvex solution set for any nonzero value of the friction coefficient. We construct an iterative algorithm that solves convex subproblems and that is guaranteed, for sufficiently smal...

We present a model describing friction due to the thermally activated formation and rupture of molecular bonds between two surfaces, with long molecules on one surface attaching to discrete or continuous binding sites on the other. The physical assumptions underlying this model are formalized using a continuum approximation resulting in a class of master-equation-like partial differential equat...

One of the ultimate goals in landslide hazard assessment is to predict maximum landslide extension and velocity. Despite much work, the physical processes governing energy dissipation during these natural granular flows remain uncertain. Field observations show that large landslides travel over unexpectedly long distances, suggesting low dissipation. Numerical simulations of landslides require ...