scholarly journals Characterising the friction coefficient between rubber O-rings and a rigid surface under extreme pressures

2021 ◽  
pp. 107378
Author(s):  
Eduardo Yanes ◽  
Nicola M. Pugno ◽  
Julien Ramier ◽  
Benjamin Berryhill ◽  
James JC. Busfield
Keyword(s):  
Friction Coefficient ◽  
Rigid Surface

Radiation of Body Waves Induced by the Sliding of an Elastic Half-Space Against a Rigid Surface

1999 ◽  
Vol 67 (1) ◽  
pp. 1-5 ◽  
Author(s):  
G. G. Adams
Keyword(s):  
Friction Coefficient ◽  
Half Space ◽  
Coefficient Of Friction ◽  
Wave Train ◽  
Tangential Velocity ◽  
Body Waves ◽  
Rigid Surface ◽  
Plane Shear ◽  
Interface Friction ◽  
The Coefficient Of Friction

The steady sliding of a flat half-space against a rigid surface with a constant interfacial coefficient of friction is investigated. It is shown here that steady sliding is compatible with the formation of a pair of body waves (a plane dilatational wave and a plane shear wave) radiated from the sliding interface. Each wave propagates at a different angle such that the trace velocities along the interface are equal and supersonic with respect to the elastic medium. The angles of wave propagation are determined by the Poisson’s ratio and by the coefficient of friction. The amplitude of the waves are indeterminant, subject only to the restriction that the perturbations in interface contact pressure and tangential velocity satisfy the inequality constraints for unilateral sliding contact. It is also found that a rectangular wave train, or a rectangular pulse, can allow for motion of the two bodies with a ratio of remote shear to normal stress which is less than the coefficient of friction. Thus the apparent coefficient of friction is less than the interface coefficient of friction. Furthermore it is shown that the apparent friction coefficient decreases with increasing speed even if the interface friction coefficient is speed-independent. This result supports the interpretation of certain friction behavior as being a consequence of the dynamics of the system, rather than strictly as an interface property. In fact no distinction is made between the static and kinetic interface friction coefficients. [S0021-8936(00)02101-2]

Self-Excited Oscillations of a Finite-Thickness Elastic Layer Sliding Against a Rigid Surface With a Constant Coefficient of Friction

2017 ◽  
Vol 85 (2) ◽  
Author(s):  
Neda Karami Mohammadi ◽  
George G. Adams
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Elastic Layer ◽  
Sliding Friction ◽  
Finite Thickness ◽  
Elastic Solid ◽  
Constant Speed ◽  
Bottom Surface ◽  
Rigid Surface ◽  
Positive Real

This investigation considers the dynamic stability of the steady-state frictional sliding of a finite-thickness elastic layer pressed against a moving rigid and flat surface of infinite extent. The elastic layer is fixed on its bottom surface; on its entire top surface, the rigid surface slides with constant speed and with a constant friction coefficient. The plane-strain equations of motion for a linear isotropic elastic solid are solved analytically for small dynamic disturbances. The analysis shows that even with a constant (speed-independent) friction coefficient, the steady solution is dynamically unstable for any finite friction coefficient. Eigenvalues with positive real parts lead to self-excited vibrations which occur for any sliding speed and which increase with increasing coefficient of friction. This is in contrast to the behavior of an elastic half-space sliding against a rigid surface in which the instability only occurs if the coefficient of friction is greater than unity. This work and its extensions are expected to be relevant in the theoretical aspects of sliding friction as well as in a variety of areas such as earthquake motion and brake dynamics.

Microstructure and Friction of Ion Beam Induced Amorphous Ti-Pd Alloys

1985 ◽  
Vol 55 ◽  
Author(s):  
J-P. Hirvonen ◽  
M. Nastasi ◽  
J. R. Phillips ◽  
J. W. Mayer
Keyword(s):  
Solid Solution ◽  
Friction Coefficient ◽  
Composition Range ◽  
Ion Beam ◽  
Amorphous Region ◽  
Transmission Electron ◽  
Solid Solution Region ◽  
Friction Measurements ◽  
Solution Region ◽  
High Equilibrium

ABSTRACTMultilayered samples of Ti-Pd with linearly varying compositions were irradiated by Xe ions at 600 keV. The induced microstructures were studied by using transmission electron microscopy and Rutherford backscattering. Mixing was found to be complete over the entire composition range, resulting in amorphous or amorphous plus crystalline structures except at the palladium-rich end, where a crystalline Pd-Ti solid solution was obtained. This is consistent with the high equilibrium solubility of Ti in Pd. In addition, significant coarsening of the microstructure caused by irradiation was found in this solid solution region.Friction measurements were carried out in air and water by using a polytetrafluoroethylene pin as a counterpart. In air the friction coefficient was independent of composition and microstructure after about 2000 passes. In water, however, after 600 passes the friction coefficient reached a steady-state value with a pronounced minimum over the amorphous region. This property was unchanged throughout the remaining 10000 passes.

A Quantitative Theory for the Computation of Tire Friction Under Severe Conditions of Sliding

1986 ◽  
Vol 14 (1) ◽  
pp. 44-72 ◽  
Author(s):  
C. M. Mc C. Ettles
Keyword(s):  
Friction Coefficient ◽  
Flash Temperature ◽  
Contact Conditions ◽  
Quantitative Form ◽  
Heating Effects ◽  
Rubber Friction ◽  
Viscoelastic Effects ◽  
Tire Friction ◽  
Pavement Friction ◽  
Metal Polymer

Abstract It is proposed that tire-pavement friction is controlled by thermal rather than by hysteresis and viscoelastic effects. A numerical model of heating effects in sliding is described in which the friction coefficient emerges as a dependent variable. The overall results of the model can be expressed in a closed form using Blok's flash temperature theory. This allows the factors controlling rubber friction to be recognized directly. The model can be applied in quantitative form to metal-polymer-ice contacts. Several examples of correlation are given. The difficulties of characterizing the contact conditions in tire-pavement friction reduce the model to qualitative form. Each of the governing parameters is examined in detail. The attainment of higher friction by small, discrete particles of aluminum filler is discussed.

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