14_ch 10 Mechanical Design budynas_SM_ch10

# 14_ch 10 Mechanical Design budynas_SM_ch10 - to 80 springs...

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274 Solutions Manual • Instructor’s Solution Manual to Accompany Mechanical Engineering Design For a clearance of 0.05 in: ID = (7 / 16) + 0 . 05 = 0 . 4875 in; OD = 0 . 4875 + 0 . 16 = 0 . 6475 in D = 0 . 4875 + 0 . 080 = 0 . 5675 in C = 0 . 5675 / 0 . 08 = 7 . 094 G = 11 . 5 Mpsi N a = d 4 G 8 kD 3 = (0 . 08) 4 (11 . 5)(10 6 ) 8(26 . 67)(0 . 5675) 3 = 12 . 0 turns N t = 12 + 2 = 14 turns, L s = dN t = 0 . 08(14) = 1 . 12 in O . K . L 0 = 1 . 875 in, y s = 1 . 875 1 . 12 = 0 . 755 in F s = ky s = 26 . 67(0 . 755) = 20 . 14 lbf K B = 4(7 . 094) + 2 4(7 . 094) 3 = 1 . 197 τ s = K B ± 8 F s D π d 3 ² = 1 . 197 ³ 8(20 . 14)(0 . 5675) π (0 . 08) 3 ´ = 68 046 psi Table 10-4: A = 140 kpsi · in m , m = 0 . 190 S sy = 0 . 45 140 (0 . 080) 0 . 190 = 101 . 8 kpsi n = 101 . 8 68 . 05 = 1 . 50 > 1 . 2 O . K . τ 1 = F 1 F s τ s = 10 20 . 14 (68 . 05) = 33 . 79 kpsi, n 1 = 101 . 8 33 . 79 = 3 . 01 > 1 . 5 O . K . There is much latitude for reducing the amount of material. Iterate on y 1 using a spread sheet. The ﬁnal results are: y 1 = 0.32 in, k = 31.25 lbf/in, N a = 10.3 turns, N t = 12.3 turns, L s = 0 . 985 in, L 0 = 1 . 820 in, y s = 0 . 835 in, F s = 26 . 1 lbf, K B = 1 . 197, τ s = 88 190 kpsi, n s = 1 . 15, and n 1 = 3 . 01 . ID = 0 . 4875 in, OD = 0 . 6475 in, d = 0 . 080 in Try other sizes and/or materials. 10-21 A stock spring catalog may have over two hundred pages of compression springs with up
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Unformatted text preview: to 80 springs per page listed. • Students should be aware that such catalogs exist. • Many springs are selected from catalogs rather than designed. • The wire size you want may not be listed. • Catalogs may also be available on disk or the web through search routines. For exam-ple, disks are available from Century Spring at 1 − (800) − 237 − 5225 www.centuryspring.com • It is better to familiarize yourself with vendor resources rather than invent them yourself. • Sample catalog pages can be given to students for study....
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## This note was uploaded on 12/13/2011 for the course EML 3013 taught by Professor Shingley during the Fall '11 term at UNF.

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