Research into the 3d roughness of a rough surface

Abstract

One of the most important parameters in determination of the deformation associated with roughness is its height on the surface. The authors study the density of probability distribution as related to the surface peak height (SPH) and estimate the mathematical expectation (ME) of SPH for the roughness values above a determined deformation level. In the contact theory, the surface is modelled as a normal random field described by the Nayak SPH formula. Since this formula is practically inapplicable in the engineering tasks, the authors propose to replace it by a simpler distribution law. For this purpose the former is compared with two other formulas obeying the most known probability distribution laws: of normal distribution (Gauss’) law and Rayleigh’s law. Comparison of these three formulas made it possible to derive a simpler yet sufficiently precise one. In the work, the numerical values of the density of SPH probability distribution and the relevant ME values at different deformation levels for all three formulas.

Wear Problems of Slide-Friction Pair

“…The diagram of the stress area (see Fig. 3) is shown according to Hamilton's theory [5,6] who studied the way of changes in the stresses of contacting surfaces depending on the values of friction coefficient f. Thus, with an increase in the friction coefficient, the highest stress values approach the outer layer of the surface and favour the emergence of slits and particle separation.…”

Wear calculation possibility of slide-friction pair “shaft-plain bearing” for four-stroke engines

“…u (2) where u -cut height from average area value; σ -surface roughness standard deviation. After we must know also the average height of surface roughnesses E{ξ a (γ)}, which according to [3] at γ>1 can be determined as follows:…”