Solution_tutorial_8_2011

# Solution_tutorial_8_2011 - 2 The reliability factor for 99...

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Solution – MECH2100 tutorial 8 2011 1. The standard reliability is 90%. An application factor of 1.5 is on the boundary between light and moderate. 30000 hours is the maximum expected of a machine on eight hour shifts. 90 million revolutions is the standard lifetime in Table 14.2. The effective radial load is 1.6[1 + 0.87(2/1.6 – 0.68)] = 2.393 kN The life is 30000*60*2000 = 3.6 x 10 9 revolutions. The basic load capacity required is C req = 2.393 x 1.5 (3600/90) 0.3 = 10.855 kN A bearing with a capacity of 11 kN is the medium series angular contact ball bearing with 35 mm bore.
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Unformatted text preview: 2. The reliability factor for 99% reliability is 0.21, and the radial load of 2 kN does not need correcting, as the axial load is less than 35% of it. Hence the life is estimated as 0.21 x 90 (6.1/2) 3.33 = 774.78 million revolutions. 3. 0.10%. 4. It turns to martensite. 5. 730 o C 6. Case hardening is a hardening of [ surface] . The [ nitriding] is a common case hardening process. Flame heat treatment can be applied to low carbon steels [ false] ....
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