نتایج جستجو برای: social friction

تعداد نتایج: 643373  

2005
Qing Zhang Yue Qi Louis G. Hector Tahir Çağın William A. Goddard

Kinetic friction during dry sliding along atomistic-scale Al 001 /Al 001 and -Al2O3 0001 / -Al2O3 0001 interfaces has been investigated using molecular dynamics MD with recently developed Reactive Force Fields ReaxFF . It is of interest to determine if kinetic friction variations predicted with MD follow the macroscopic-scale friction laws known as Coulomb’s law for dry sliding and Stokes’ fric...

2001
Elena Garcia Pablo Gonzalez-de-Santos

Dynamic modelling is an important issue in legged locomotion. However, friction has been neglected in most studied models. The aim of this work is the experimental determination of frictional effects over leg dynamics. For this purpose, previous work on friction modelling in robot manipulators (1), (3), has been followed and similar results have been achieved. However, a new friction component ...

2007
Janusz Lubas

This work revealed the results of comparative surveys of the impact of formed surface layer TiN and CrN and two component surfaces layer TiN-steel and CrN-steel. The slide couple worked in conditions of lubricating the friction area with Lotos Syntetyk 5W/40 and Castrol GTX Magnatec 5W/40 engine oils. In the friction couple the counter sample was made from CuPb30 bearing alloy. The tribological...

2001
C. Canudas-de-Wit

A new dynamic friction force model for the longitudinal road/tire interaction for wheeled ground vehicles is validated via experiments with an actual passenger vehicle. Contrary to common static friction/slip maps, this new dynamic friction model is able to accurately capture the transient behavior of the friction force observed during transitions between braking and acceleration. A velocitydep...

2012
Seong Ik Han Chan Se Jeong Soon Yong Yang

A robust positioning control scheme has been developed using friction parameter observer and recurrent fuzzy neural networks based on the sliding mode control. As a dynamic friction model, the LuGre model is adopted for handling friction compensation because it has been known to capture sufficiently the properties of a nonlinear dynamic friction. A developed friction parameter observer has a si...

Journal: :Biochimica et biophysica acta 1995
J S Lolkema

Friction analysis is proposed as the application of general control analysis to single enzymes to describe the control of elementary kinetic steps on the overall catalytic rate. For each transition, a friction coefficient is defined that measures the sensitivity of the turnover rate to the free energy of the transition state complex of the transition. The latter is captured in a single property...

2009
Fathi Namouni

ABSTRACT Dynamical friction arises from the interaction of a perturber and the gravitational wake it excites in the ambient medium. This interaction is usually derived assuming that the perturber has a constant velocity. In realistic situations, motion is accelerated as for instance by dynamical friction itself. Here, we study the effect of acceleration on the dynamical friction force. We chara...

2013
Jun Young Yoon David L. Trumper

Two distinct regimes are considered when it comes to friction: gross-sliding regime and presliding regime [1]. Friction in the gross-sliding regime contains familiar and classic concepts of static friction, Coulomb friction, and Stribeck curve. It is more intriguing, on the other hand, that friction in the pre-sliding regime behaves like a non-linear spring with hysteresis, significantly impact...

2017
Bettina Suhr Klaus Six

In the discrete element simulation of granular materials, the modelling of contacts is crucial for the prediction of the macroscopic material behaviour. From the tribological point of view, friction at contacts needs to be modelled carefully, as it depends on several factors, e.g. contact normal load or temperature to name only two. In discrete element method (DEM) simulations the usage of Coul...

Journal: :journal of modern processes in manufacturing and production 0
reza nosouhi modern manufacturing technologies research center, najafabad branch, islamic azad university, najafabad, iran saeed behbahani department of mechanical engineering, isfahan university of technology, isfahan, iran saeid amini manufacturing department, faculty of engineering, university of kashan, kashan, iran mohammad reza khosrojerdi manufacturing department, faculty of engineering, university of kashan, kashan, iran

a new dynamic friction model for modeling of elliptical vibration assisted turning (evat) was developed in this research. the periodic change of the friction force direction is known to be one of the most important causes of this phenomenon. in modeling of machining processes (including the evat process), static coulomb friction model was employed by most of the researchers. because of the peri...

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