Mechanisms of friction and wear between solid surfaces

SYSTEMATIC ABSTRACTS solutions made possible the indirect measurement of point-wise juncture conditions at the interface of sliding contacts; the actual mechanical mode is only described schematically. The solutions are most suitable for matching the solutions at the interface, given by juncture condition. Green’s Function of Radial Displacement in a Circular Disc Due to Unit Normal and Tangential Loads. C. W. Ng (Wright-Patterson AFB, Ohio, Directorate of Materials and Processes), Preprint copy (IgO?.) rg pp., 5 refs.; Rensselaer Polytechnic Inst. Troy, N.Y.; N 62-16344, T.P.A., 2 (16) (1962)921). Using the method of Muskhelishvili, the Green’s function of radial displacement is obtained in a circular disc due to a unit normal and a unit shear traction at the boundary. This Green’s function is useful in the study of contact problems in sliding as well as in rolling, i.e. the important problem of elasto-hydrodynamics is included. An example is carried out for the distribution of heat generation due to a rigid rider against an elastic slider which is in the form of a circular disc. Measurement of Point-wise Juncture Cond&ion of Temperature at the Interface of Two Bodies in Sliding Contact. F. F. Ling and T. E. Simkins, Tech. DOG.Rep. Rensselaer Polytechnic Inst., (rg6r-rg6z) 30 pp., 3 refs.; N 62-16323, T.P.A., z (16) (1962) 929. An apparatus is described for bringing a rider specimen and a slider specimen into continuous sliding contact so that significant temperatures at the interface are achievable. The design is such that the flow fields of heat in the specimens would be at most two-dimensional, i.e., within engineering approximations; this fact makes possible the measurement of temperatures of the specimens without disrupting the flow fields of heat. Typical data are presented of speed, normal load, frictional resistance and temperatures at strategic locations on the specimens. Using the heat-equation solutions obtained previously for the configurations concerned, contact-surface temperature distributions of bath the specimens are calculated from experimental data. Results give the point-wise, temperature juncture condition at the interface. Mechanisms of Friction and Wear between Solid Surfaces K. E. Boyd, C. T. Rollins and A. D. Thomas (Utah University, Salt Lake City, Utah), (1962) 62 pp., 145 refs.; N 62-11084, T.P.i4., 2 (4) (1962) ‘53. A low-velocity friction testing machine for

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surface velocities of from I.0 ft./see to 15.0 ft./set and a high-velocity friction testing machine for surface velocities of from 1.0 ft./see to 200 ft./set are designed, fabricated and used to test a number of pairs of solid materials. Coefficients of friction as a function of several parameters were measured and plotted. It was found that a unique interface temperature between rubbing materials does not exist, but rather a random extremely variable temperature profile of considerable magnitude does exist. Data were obtained which give evidence for deducing the effects of reactivity and solid solubility on the friction process. Friction Measurement with the Tapered Spindle Top. J. W. Givens and S. K. Talley, Lubrication Eng., r8 (10) (1962) 443-449; 6 figs., 3 tables, 5 refs. The Tapered Spindle Top, a new apparatus for kinetic friction measurements, is described. This device is characterized by a “line” rather than a “point” contact between the bearing surfaces as in the Four-Ball apparatus. The new machine covers a load range intermediate between that of the Four-Ball and journal bearing test machines and for this reason is especially well suited for studying the transition between hvdrodvnamic _ . and boundary friction. A method has been developed for resolving friction in the transition reg’,on of lubrication into hydrodynamic and boundary components, thereby affording a means of measuring oiliness. At low speed the top is capable of measuring kinetic boundary friction and provides a sensitive and rapid method for determining the variation of coefficient of friction with velocity, an important property of lubricants in many practical applications. Study on a Radioactive Method foe Estimating the Lubricating Qualities of Compound Oils by Using the Wear of Surfaces. (in English) D. Paveiescu, I. Ifiuc and S. Barbul, Rev. Mecan. AP$., 6 (4) (1961) 539-547; A#. MecR. Rw., r5 (8) (1962) 681. Eouinment for Measuring Vibrations in A&friction 3earings. Z. landa, En&h Abstracts of Selected Articles .from Soviet Bloc and M~ainland China Technical Journals, Ser. 4. No. g (1961). U.S. Dept. Commerce, OTS, Washington 25, D.C.; A&s%. &feck. Iiezl., ~5 (8) (1962) 681. Cavitation Tunnel Tests with Merchant Ship Propellers. (in English) I-I. Lindgren, Mead. Stat. Skeppsprov. Amt. G&borg, No. 48 (1961) 43 pp., 11 rcfs.; l%Ppl. Merh. Rev., rfj (9) (1962) 759. U’eav, 6 (1963) 81-w