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Bending stress in horizontal pressure vessel saddle base plate

Bending stress in horizontal pressure vessel saddle base plate

Bending stress in horizontal pressure vessel saddle base plate

(OP)
I am looking for a correct formula for the bending stress in the saddle base plate of a horizontal pressure vessel.  The current formula I have has incorrect units.  

fb = [(6*M)/(tb^2)] is the formula I'm using (units of lb/in instead is lb/in^2), where fb = bending stress, M = bending moment, tb = base plate thickness.

I have limited access to references so I would appreciate any formula or online reference site anyone could provide.  

Also, if this is the correct formula could someone explain to me why the units are not in psi.

RE: Bending stress in horizontal pressure vessel saddle base plate

Have you found your answer to this?  I just came across your post.
I think you're on the right track and the formula that you are using is for a unit length of base plate. The formula for the section modulus is S = b*t^2 / 6, and the bending stress is M/S Substituting you get M/S = 6*M / b*(t^2)
Then if you are looking at a unit length of the base plate, b=1, you reduce to your formula 6*M/t^2 (which actually is units of psi if you leave the b=1" term in the denominator.

RE: Bending stress in horizontal pressure vessel saddle base plate

We want any help to establish a magazine

RE: Bending stress in horizontal pressure vessel saddle base plate

I am surprised that so far temperature is not mentioned in your formulas (most of my pressure vessels involve temperature).  If your pressure vessel has hot temperatures, you have a longitudinal growth that must be taken out by some longitudinal expansion (rather obvious and most likely taken care of) but there is a circumferential growth (of the shell) that causes a hogging of the saddle (the base plate will be of a lower temperature, therefore less thermal expansion, causing a hogging and bearing on the extremities of the saddle).

This may not be your case, but recently I was involved in a repair to the foundations of a rather large (thermal) vessel that was destroying its foundation.

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