Introduction to Contact Mechanics Part 4 ppt

... Orowan, Nature 1 54, 1 944 , p. 341 . 11. T.C. Baker and F.W. Preston, “Fatigue of glass under static loads,” J. Appl. Phys. 17, 1 945 , pp. 170–178. 12. G.F. Stockdale, F.V. Tooley, and C.W. ... r and extrapolate back to r = 0. r 1 2 3 4 r K 1 best estimate 1 2 3 4 3 .4 Sharp Tip Crack Growth Model 55 Fig. 3 .4. 1 Crack velocity versus stress intensity factor showing thre...

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... fracture mechanics as it allows results from laboratory scale tests to be applied to large scale fracture problems. )2()1( II KK  Si 3 N 4 Al 2 O 3 Glass K c (MPa )Material m 1  43   8 4   35 Steels Al ... alloys Polymers Si 3 N 4 8 4   25.0   10010   30030   Plastic Zone Size Estimate Consider inelastic and permanent deformation at the crack tip (stresses are...

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... losses due to heat, sound, etc.). The resulting two separated atoms have the potential to form bonds with other atoms. The atoms, now separated from each other, can be considered to be a “surface.” ... directions on a particular atom, and the atom takes up an equi- librium position within the material. Now consider an atom “B” on the surface. Such an atom is attracted by the many ato...

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... crack tip is: E c G 2 πσ = (2 .4. 5a) Thus, substituting Eq. 2 .4. 1b into Eq. 2 .4. 5a, we have: E K G 2 1 = (2 .4. 5b) Linear Elastic Fracture Mechanics 38 In Eq. 2 .4. 1b, Y is a function whose ... cYK a πσ = 1 (2 .4. 1b) The coordinate system for Eqs. 2 .4. 1a and 2 .4. 1b is shown in Fig. 2 .4. 1. In Eqn. 2 .4. 1b, σ a is the externally applied stress, Y is a geometry fa...

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... trajectories, (g) τ max trajectories. Fig. 5.3.2 Stress trajectories and contours of equal stress in MPa for Boussinesq “point 0 1 2 3 4 r 4 −3 −2 −1 0 z 0 1 2 3 4 r 4 −3 −2 −1 0 z 0 1 2 3 4 r 4 −3 −2 −1 0 z 0 ... 1 2 3 4 r 4 −3 −2 −1 0 z 0 1 2 3 4 r 4 −3 −2 −1 0 z 0 1 2 3 4 r 4 −3 −2 −1 0 z 0 1 2 3 4 r 4 −3 −2 −1 0 z P 0 1 2 3 4 r 4 −3 −2 −1 0 z 0 1 2 3 4...

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... University Press, Cambridge, U.K., 1985. 4. 5. I.N. Sneddon, “Boussinesq‘s problem for a rigid cone,” Proc. Cambridge Philos. Soc. 44 , 1 948 , pp. 49 2–507. 6. S. Timoshenko and J.N. Goodier, ... “The Hertz contact problem with finite friction,” J. Elastoplast. 5 3 4, 1975, pp. 297–319. 10. J. Tseng and M.D. Olson, “The mixed finite element method applied to two- 11. N. Okamoto...

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... aware of the complex nature of the stresses and their 0 1 2 3 4 r 4 −3 −2 −1 0 z (a) 0 1 2 3 4 r 4 −3 −2 −1 0 z (b) 0 1 2 3 4 r 4 −3 −2 −1 0 z (c) − 0 . 3 0 0 − 0 . 2 0 0 − 0 .1 0 0 − 0 .0 5 0 − 0. 0 2 5 − 0 . 1 0 0 − 0. 05 0 − 0. 0 10 − 0.00 5 0 . 0 0 0 0 . 0 0 0 0 . 0 2 5 0. 013 0 . 0 0 6 0 .0 0 6 0 . 0 0 3 0 . 0 02 0 .00 3 0.0 13 − 0.020 − 0. 0 05 0 . 0 0 5 0 .0 1 0 0. 020 0.0...

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... 22). 0 1 2 3 4 4 −3 −2 −1 0 z/a o 0 1 2 3 4 4 −3 −2 −1 0 z/a o 0 1 2 3 4 r/a o 4 −3 −2 −1 0 z/a o 4 −3 −2 −1 0 r/a o 4 −3 −2 −1 0 4 −3 −2 −1 0 4 −3 −2 −1 0 4 −3 −2 −1 0 4 −3 −2 −1 0 (a) (b) (c) 0.005 − 0 . 3 00 − 0.200 0.005 0 . 0 1 0 0.010 0 .0 05 0 . 020 0.02 0 0.00 5 − 0.0 25 − 0.050 − 0. 1 00 0.010 0.0 05 − 0.20 0 − 0.100 − 0 .060 − 0 . 040 − 0 .020 − 0.010 − 0.008...

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... 32 3, 1997, pp. 727–736. 34. W. Hirst and M.G.J.W. Howse, “The indentation of materials by wedges,” Proc. R. Soc. London, Ser. A311, 1969, pp. 42 9 44 4. pp. 42 0 43 5. 22. D.M. Marsh, “Plastic ... 1970, pp. 48 0 49 4. 28. C. Hardy, C.N. Baronet, and G.V. Tordion, “The Elastic-plastic indentation of a half- space by a rigid sphere,” Int. J. Numer. Methods Eng. 3, 1971, pp. 45 1 4...

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