Question

i was working on this problem but im a little confused on how to use table-17 “preferred size and renard numbers” can anybody explain to me how to get the answer 1(1/4). thank you!!

1.12 A solid circular rod of diameter d undergoes abendung moment M = 1000 lbf.in inducing a stress U-32M/tid. Usmg a material strength ofaskpsi and a design foctor of 2.5. Determind the minimum diameter of thered. Select a preferred fractional diameter and determme theresulting factor of safety nd=2.5 S-25kpsi M=1000 lbf in G=S a5kpsi U-S nd 25kpsi = 10kpsi (10cpsi -10000psi 2.5 l kusi) Step2 Calculate circular rod I G= 32M d = 32(1000) ST (10,000) d² = 32M TO Id = 1.00615 in d = 33M TO

why cant it be 1.12 or any other close to 1.00615. thank you!!

Answer 1

Anst- data given and famding moment z M = 1000 lbfim inducing a blocs5 6 = 321 1 3 www. *** Deslon Pucony = 2,5 Cructor of Scistey). non muroiul shaxmgth 5 = 25 kpsi ** minimum diameters of Rod dimin = ? Noco Alauble staon gth of mulcorcu crioul Sum Sou = 9 - 25 kpsi - HOS 2.5 Swell = 10,000 psi nm@ wa Noco NOCO - So... .: dmin = 23. des E tats .; 6 = 32m Td3 w Now For dmin let 6 = 6 . so. Ocell = 39.m - Say S T amin 32 x (1000) va (10,000) .: dmin = 1,006159 inch mmm wy The calculceted diameter 1.006159 is mine size of shaft which is required for safer opesution of given condition. But In geneacul pouchile we select stemdused Size of of ood which is given in table no.17. ng NOW as pero table No. 17 Stendered size available is ...0.8, 1.00, 1(74) ...... my Now, as per our calculation min. Required diameter is! w 5), Slemdused size which is closed to This is 1 cm d 30°

Fraction of Inches dass es su L . 1.1.1, 1.2, 24, 25, 2, 3, 37,3, 3), 4.4.4.4.5.51, 58, 59, 6, 6, 7, 7, 8, 85, 9.9, 10, 109, 11, 114, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 1920 Decimal Inches 0.010,0.012,0.016, 0.020,0,025,0.032, 0.040,0.05, 0.06,0.08, 0.10,0.12,0.16,0.20, 0.24, 0.30, 0,40,0.50, 0.60, 0.80, 100, 1.20. 1.40, 160, 1.80, 20, 24, 26, 28, 3.0, 3.2, 34, 36, 3.8, 4.0, 4.2, 44,46, 4.8.5.05.2,5,4,5,6,58,60,70,75,8.5, 9.0,9.5, 100, 10.5, 110, 115, 12.0, 12.5. 13.0, 13.5, 14.0, 14.5, 15.0, 155, 160, 16.5, 17.0, 17.5, 180, 18.5, 190, 19.5, 20 Millimeters 0.05, 0.06, 0.08, 0.10,0.12, 0.16,0.200.250.30. 0.40 0.50, 0.60.0.70.0.80, 0.90, 1.0, 1.1, 1.2. 14, 15, 16, 18, 20,22,25,28,30,35, 40,45,50,55,60, 65, 70, 80, 90, 10, 11, 12, 14, 16, 18, 20, 22, 25, 28, 30, 32, 35, 40, 45, 50, 60, 80, 100, 120, 140, 160, 180, 200, 250, 300 Renard Numbers Ist choice, R5:1, 16, 25, 4, 6:3, 10 2d choice, RIO: 1.25, 2, 3.15, 5,8 3d choice, R20:1.12, 1.4, 1.8, 2.24.2.8, 355, 4.5.5.6, 7.1.9 4th choice, R.40:1.06, 118, 132, 1.5, 1.7, 1.9.212.236, 2.65, 3, 3.35, 3.75, 4.25 4.75, 53,6, 6.7, 7.5.8.5.95 May be multiplied or divided by powers of 10

w Nocu if we ket teke d = I it will be d <dmin so factor of Safety oy design factor will be compoomussed and it will be less thum 2.5 » SO, (we will take iminedicite next stemduocd size which is 1194) = d.- 514 wy now 6 = 32.m = 32 x 1000 x ( 523 ..6 = 5215.189 Psi mm© Now indused stoess $ = 6 = 5215.159. -NEW Fechod of safety po = = 25000 S215.159 ros = 4,79 mm my cwcwated Tas > 2.5 50 given condition cupol be scarishied. spacrescd Funciona dicmeter = 5 (from table No. 17). and the resucing design Feictoy = 4.79. Mote :- Now These is no cmy stem dened size between 1 cmd sin Thurs way we com not use 1-12.
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