Knowledge requires both freedom and friction. Freedom to set up our epistemic goals, choose the subject matter of our investigations, espouse cognitive norms, design research programs, etc., and friction (constraint) coming from two directions: the object or target of our investigation, i.e., the world in a broad sense, and our mind as the sum total of constraints involving the knower. My goal ...

In this investigation three effects are included in a recently developed scale-dependent multi-asperity model of elastic contact and friction. First, a Weibull distribution of asperity heights is used, which allows the skew and kurtosis to be varied, but not independently of each other. Second, the effect of non-constant radii of curvature of the asperity summits, with the curvature varying wit...

In this review, we discuss the current knowledge on the tribology of human skin and present an analysis of the available experimental results for skin friction coefficients. Starting with an overview on the factors influencing the friction behaviour of skin, we discuss the up-to-date existing experimental data and compare the results for different anatomical skin areas and friction measurement ...

This paper presents an algorithm to estimate friction parameters of a real control valve. Data are collected from a valve installed in a bench, submitted to different input signals and subject to different friction forces. Two different parameter sets are obtained, based on distinct methods. These parameter sets are applied in the Karnopp friction model, generating two versions of the same mode...

This paper reviews rock friction and the frictional properties of earthquake faults. The basis for rateand state-dependent friction laws is reviewed. The friction state variable is discussed, including its interpretation as a measure of average asperity contact time and porosity within granular fault gouge. Data are summarized showing that friction evolves even during truly stationary contact, ...

The effect of an asymmetric distribution of asperity heights is accounted for in a recently developed scale-dependent multiasperity model of contact and friction. A Weibull distribution of asperity heights is used which allows the skew and kurtosis to be varied, but not independently of each other. The contact and friction model used includes the effects of adhesion and of scale-dependent frict...

This article focuses on the modeling of two-wheel mobile robot with differential chassis, which is moving in the plane. According to the application, it can be modeled with different accuracy levels depending on structural limits and other physical impacts. Main goal of this article is to include the effects of friction into the mobile robot dynamics. Four basic models of friction are combined ...

The distributed Maxwell-slip model provides a convenient way to describe the presliding friction behavior. The modified single-state Maxwell-slip (MMS) model is proposed with the main benefit to require two concentrated parameters only when describing the smooth hysteresis of the presliding friction. The model is rate-independent at both, saturated and unsaturated hysteresis, and is consistent ...

Abstract A subloading-friction model is formulated to describe the smooth transient variation from static friction kinetic friction, recovery after sliding velocity decreases, and accumulation of displacement under cyclic loading contact stress. In past relevant studies, however, formulation used for simulations limited hypoelastic-based plasticity framework, validation test data metal-to-metal...

This paper presents a new dynamical friction model structure which allows accurate modeling both in the sliding and the presliding regimes. Transition between these two regimes is accomplished without a switching function. The model incorporates a hysteresis function with nonlocal memory and arbitrary transition curves. These last aspects prove essential for modeling presliding friction that is...