Question

[3]. (3 marks) Figure below shows a bolted joint subjected to an external force P that fluctuates from 0 to 7 kips The steel bolt specification is 5/8"-11 UNC, SAE grade 5 material with rolled threads. The clamped members are steel of length 1.25 in each (with a total length of 2.5 in). Plain wide washers are utilized at both ends of the bolt. [a]. Using the Goodman line, determine the factor of safety guarding against fatigue failure for the two cases, (i) no pre-load is applied to the joint, (ii) a recommended pre-load is applied to the joint assuming a non-permanent connection. For the calculation of member stiffness km: neglect the frusta associated with the washers at the two ends of the bolt. For this calculation, assume that no stress concentration factor exists in the problem. [b]. Check the joint for maximum stress in the bolt not exceeding the bolt proof stress under static loading. Again, for this calculation, assume that no stress concentration factor exists in the problem. d-2.5 [c]. Repeat [a] by considering stress concentration factor in fatigue in the bolt threads. Repeat b] with theoretical stress concentration factor in the bolt threads to be the same as in fatigue (i.e., notch sensitivity, g 1)

Answer 1

d0 6250 dん: 0,5069 Ae 50-1160 Se the 2.5-소 七.7% ) E 0-2260 6) E Km= 0.478でE) = 0.1912E m 01120086

e load au. 17.289 kip A C A E ヒ 137 6-2260 226 0 2260 А.calde Seubs tilutiug all Se C Sut) alue Ja k Nso (100-765 50 (81.2-765)+1ƠDA 4.8

Patt冫 2-17 a. 0.2260 0-2260 Sulutitutiug al valuey- C 50や100 Ng 悍.28 At

nt Juade eloaol 6a = 수.SX185 x 3 14,4×103 PSİ Ac Nf 드 0.70 So (E12-o)+100 x1y