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Simple Question, Bolt Axial Load
I trying to get an approximate value of Torque to apply to 2 bolts in a clamp to achieve 5 and 10 metric tons of clamping force and I seem to be getting an answer that is not realistic.
Here is a quick diagram. (Tube with 2 clamps and 2 bolts, with nuts)
[IMG]http://www.engineersedge.com/engineering-forum/attachment.php?attachmentid=1157&stc=1[/IMG]
Bolts are 3/8"-16 Hex Head. 304SS
Tensile Strength ~ 75000psi
Tensile Stress Area = 0.0775in^2
Therefore: Max Tensile Load (P) = 0.0775 * 75000 = 5812.5lbs.
Proof Load = 90%(P) = 5231lbs.
Typical Clamp Load = 75% Proof Load = 3923.lbs.
Torque = K x d x F
K = Nut Factor = 0.2 (Stainless steel bolt and nut with lubrication?)
d = Nominal Dia. = 3/8"
F = 3923lbs
T = 24 ft.lbs.
This torque Seems to meet recommendations I see in my industry for this type and size of fastener. But my question is, because there are 2 bolts creating this clamping force (3923lbs) would I have to apply half the torque? I.e 12ftlbs to each bolt. If torque was only applied to one bolt in this situation no axial load would be applied to the tube. Thank for all the help you can give me.