Adhesive Wear of Fibers

Abstract

In our previous paper, 1)2) the mechanism of wear phenomena of fibrous materials was classified into four types under various rubbing conditions. And the relationship between the wear resistance and its mechanical properties was described experimentally as follows;Amount of wear loss ∝total frictional force/modulus×tensile strength×elongationThe purpose of the present paper is to describe quantitatively the mechanism of adhesive wear. Adhesive wear takes place whenever two solid surfaces are in rubbing contact, whether lubricated or not, and remains when all other types of wear are eliminated, so that adhesive wear may be distinguished as the most fundamental of the several types of wear.In this analysis the number of contacts of small protuberances in the surface of fiber, I is assumed to be hm/u, where h is the depth of deformation of the surface, u is the distance between the protuberances, and m is a constant.(1) The general fomula for the relation between the real area of contact, A, and the load W is obtained as follows;A=C·Wm+2·φ/m+2·φ·λ (1)where λ=1 as plastic deformation, and λ=3/2 as elastic deformation and φ is a constant in reference to the shape of the protuberance, and C is a constant, (2) The general fomula for the relation between the volume of the worn material V and the load W is obtained as follows;V=C·WK (2)K=φ(ψ-1)+m/2·φ·λ+m (3)where ψ is a constant due to the shape of the worn particles.(3) In the case of polypropylene monofilaments, K seems to depend upon Young's modulus.(4) The temperature dependence of dead weight W/d under which the fibers are broken at a certain NB, shows maxima. In the case of log NB=4, the maxima appear at about 50°C and 100°C. The temperature dependence of W/d for adhesive wear and shaving wear presents similar tendency. Consequently, the temperature dependence of wear resistance in both the types of wear seems to depend upon its polymer properties.