thread strength

[picasa]

a hollow pipe has threads on the outer surface. Load is exerted on the threads axially thru a flange that turns into the threads. I am calculating the maximum axial load that the pipe can take before the threads shear. I used Machinery's handbook (26th edition) - page 1490 - equation (1) to find length of engagement Le. If that length of engagement is available then the allowable axial load = Allowable axial stress*At, where At is calculated per equation (2) on page 1490. If the actual length of engagement that is available is less than Le calculated per equation (1) then the allowable axial load should be reduced by the ratio of the two lengths (available L / Le per equation (1)) . Is this approach correct? I guess I should also be looking at the allowable load that is calculated by multiplying available cross sectional area of the hollow pipe and the allowable tensile stress of the material. Please comment.

 

[EdStainless]

You need to watch the total load.
If it is rather high you will get some reduction is diameter that will reduce thread engagement. This doesn't happen with bar.

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Corrosion, every where, all the time.
Manage it or it will manage you.

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