Bend Calculation

[nilshs]

Hello,

I need some help in bend calculation. The Facts:

I have an Elbow R=5 - 8" with a wallthickness of 0.277" so now I need to now how long is the tube if it is not bended.

Or: To get a R5 8" Elbow - how long must be the tube?

Thanks for any reply.

Nils

 

[metman]

A ballpark number for nuetral axis is 0.44 (this number varies for material, temper and...)for solid material. Since maximum stresses (compressive and tensile) are at the extreme fibers, this should still give you a reasonably close guess for tubing. In other words; If your inside radius is 6" and you have an outside diameter for your tube of say 2", then .44 x 2 = .88. So your n.a. radius is 6.88. 6.88 x 3.14/4(for 90deg bend)= 5.4".

Hope this helps.