12friction and lubrication of thin liquid films

... theory of hydro- dynamic lubrication pointed out that one of the least understood and urgent areas of research is that of thermohydrodynamics In the discussion of parallel surfaces and mixed lubrication, ... proposed by Elord and Adams and studied the lubri- cant film rupture and reformation effects on grooved bearing performance for a wide range of operating parameters The comparison of their theore- ... wedge, microasperity and cavitation lubrication, asperity colli- sions, and squeeze effects do not provide sufficient fluid pressure to be considered a primary source of beneficial lubrication in parallel

Ngày tải lên: 05/08/2014, 09:20

... friction with load and rolling speed In the isothermal regime, it is expected that the surface roughness, the modulus of elasticity of the coated and base materials, and the thickness of the coated ... of the coated materials influence the coefficient of friction The modulus of elasticity decreases the coefficient of friction in the isothermal and nonlinear regimes The thermal properties of ... increase, but at much slower rate than in the isothermal and the nonlinear regimes The magnitude and posi- tion of the maximum value of the coefficient of friction are influenced by the surface roughness,

Ngày tải lên: 05/08/2014, 09:20

... 80 and 100 for Cheng's test, 50 and 60 for Hirst's test, and 40 and 60 for Johnson's test (A = ho/Sc, and Sc = ,/:fs:, where S1 and S2 are surface roughness of contact surfaces, CLA.) Because ... and surface coating The formulas were used for evaluating rolling friction, and traction forces in the isothermal, non- linear, and thermal regimes of elastohydrodynamic lubrication Because of ... calculated by (Fig 7.18): Eh = modulus of elasticity of base material E, = modulus of elasticity of coating material E , = modulus of elasticity of coated surface h, = coating film thickness hd

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... strength of the softer material (psi) h = depth of wear of the softer material (in.) k = wear coefficient Values of k for different material combinations are given in Table 8.2 The depth of wear of ... Y N., and Gavrikov, Y A., “Friction and Scoring under the Conditions of Simultaneous Rolling and Sliding of Bodies,” Wear, 1968, Vol 1 1 O’Donoghue, J P., and Cameron, A., “Friction and Temperature ... wear of mechanical components has been estimated to cost the U.S economy between 6% and 7% of the gross national product Understanding the wear process and its control is, therefore, of major

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... function of the density of the fluid and the modulus of elasticity of the impacted material [37, 381 The effect of the high pressures on wear is partly enhanced by the shearing action of the liquid ... of cavitation erosion pitting and wear Erosive wear occurs due to the change of momentum of a fluid moving at high speed It has been observed in the wear of turbine blades and in the elbows of ... dust, and hard debris from the environment These particles first pene- trate the metal and then tear off relatively large particles from the surface It is one of the most common forms of wear and

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... 2,O and U subscripts in Eq (9.7) by m, i, and I , respectively In the above equations Ao, A,, and A, are the cylindrical areas of the outer, inner, and interface surfaces, respectively Au,, and ... energy of the electron beam, the exposure time, and the material of the specimen The radioactivity, which naturally decays with time, is also reduced with wear of the bombarded surface The rate of ... of reduction of the radioactivity is approximately proportional to the depth of wear The amount of wear can therefore be detected by monitoring the radioactivity of the specimen and using a calibration

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... thermal cracking and thermal fatigue High temperature can also cause change of the material properties of the surface layer, acceleration of oxidation, poor absorption of oil, and material degradation ... the contact and variation of Hertzian contact stress, the magnitude and the extent of the microslip area is a function of time However, because of the high stiffness of the clutch system, the ... This result is interesting in view of the finding of Radin et al [88] that increased calcification and stiffening of the rabbit joints occurred as a result of repeated high impact load It shows

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... of 0.15 mN at the bushings and 0.04 mN in the bearing of the Trang 9Suzuki et al [12] compared the friction and wear of different solid lubricant films by applying them to riders and disks of ... H., and D’Silva, N S., “Effect of Motion and Process Parameters on the Prediction of Temperature Rise in Fretting Wear,” Wear, 1985, Vol 106, 101 Bowden, F P., and Tabor, D., “Friction and Lubrication,” ... C., and Ludema, K C., “Wear Models and Predictive Equations: Their Form and Content,” Wear, 1995, Vol 181-183, pp 443-457 112 Kayaba, T., and Iwabuchi, A., “The Fretting Wear of 0.45%C Steel and

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... The area of the hysteresis loop diminished progressively with the number of cycles and the rate of decay of the loop area also decreased with the number of cycles Johnson [4] and O’Connor and Johnson ... Chapter I3 within the region of gross slip The dependency of the creep displacement on the rate of ball displacement at the onset of dwell can be readily seen Figure 13.15 shows the plot of this relationship ... temperature through the thickness in the process of adjusting the arc voltage and the rate of flow of the liquid nitrogen to achieve repeatable thermal cycles of the desired range The extrapolated temperature...

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... Lindberg, R A., “Processes and Materials of Manufacture,” Allyn and Bacon, 1977, pp 628-637 “Wear Control Handbook”, ASME, 1980 Szeri, A Z., Tribology: Friction, Lubrication and Wear, Hemisphere, ... Scoring Under the Conditions of Simultaneous Rolling and Sliding of Bodies,” Wear, 1968, Vol 11, p 291 Kelley, B W., and Lemaski, A.J., Lubrication of Involute Gearing,” Proc Inst Mech Engrs, 1967-68, ... Konishi, T., and Nishizawa, Y “Fundamental Research on Gear Lubrication, ” Bull JSME, 1962, Vol 5( 19), p 561 Drozdov, Y N., and Gavrikov, Y A., “Friction and Scoring Under the Conditions of Simultaneous...

Ngày tải lên: 13/12/2013, 03:15

... Selection and Application, Duane Tandeske 73 Zinc Handbook: Properties, Processing, and Use in Design, Frank Porter 74 Thermal Fatigue of Metals, Andrzej Weronski and Tadeusz Hejwowski 75 Classical and ... Revised and Expanded, Earl Logan, Jr 86 Vibrations of Shells and Plates: Second Edition, Revised and Expanded, Werner Soedel 87 Steam Plant Calculations Manual: Second Edition, Revised and Ex panded, ... Understanding Gear Noise, J Derek Smith Chains for Power Transmission and Material Handling: Design and Applications Handbook, American Chain Association Corrosion and Corrosion Protection Handbook,...

Ngày tải lên: 13/12/2013, 03:15

... Selection and Application, Duane Tandeske 73 Zinc Handbook: Properties, Processing, and Use in Design, Frank Porter 74 Thermal Fatigue of Metals, Andrzej Weronski and Tadeusz Hejwowski 75 Classical and ... Revised and Expanded, Earl Logan, Jr 86 Vibrations of Shells and Plates: Second Edition, Revised and Expanded, Werner Soedel 87 Steam Plant Calculations Manual: Second Edition, Revised and Ex panded, ... Understanding Gear Noise, J Derek Smith Chains for Power Transmission and Material Handling: Design and Applications Handbook, American Chain Association Corrosion and Corrosion Protection Handbook,...

Ngày tải lên: 04/07/2014, 14:20

... “Axi-Symmetric Contact on Thin Compliant Coatings,” Journal of Mechanics and Physics of Solids, 1981, Vol 29, p 89 34 Maugis, D., and Barquins, M., “Fracture Mechanics and the Adherence of Viscoelastic ... of the two bodies respectively = N x N matrix of influence coefticients F = N x vector of forces Y = N x vector of slack variables (or final separation) e = N x vector of 1’s E = N x vector of ... Properties of Elastic Bodies in Contact, Mechanics of Contact between Deformable Bodies, University Press, Delft, Netherlands, 1975 32 Greenwood, J A., and Johnson, K L., “The Mechanics of Adhesion of...

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