Combined loads (Hoop stress and other loads)

[pegus]

Good day Everyone,

http://www.eng-tips.com/

I was analyzing my pipe line (ANSYS 16.0) configuration considering the spring reactions that the expansion joints that I include in my pipe line will produce.

This pipe line will have internal pressure, which it will produce hoop stress and longitudinal stress.

Can I just add the hoop stress and longitudinal stress due to internal pressure to the resultant stress (Bending, axial, torsional, etc) due to the expansion joint reactions?

I know that to apply the superposition principle the forces must have the same direction, but I believe that adding these stresses will produce a conservative result.

The reason I am asking this is because when I add too many inputs in ansys, it appears that the stresses get really high, that's why I want it to do it separately.

Is this approach ok? or what advice do you recommend?

Thanks in advance!

 

[TGS4]

If you have three apples, and you add four oranges, how many bananas do you have?

That's the exact same as the question you asked.

Stresses are tensors, and all algebra needs to be done at the component level. So, no.

 

[LittleInch]

" expansion joints that I include in my pipe line " - please explain.

Expansion joints are normally best avoided, especially on a "pipe line", but maybe you mean other things.

Your design code will tell you how to add the stresses together - which one are you using?

Expansion joints is a loose term - what do you mean?

If you've got expansion that needs relieving, then you might well be getting high stresses.



Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[racookpe1978]

I was analyzing my pipe line (ANSYS 16.0) configuration considering the spring reactions that the expansion joints that I include in my pipe line will produce.

You're backwards.

Treat the PIPES and the changes in length (and thus stress) THEY create by changes in temperature and operating conditions as the SOURCE of your stresses.
THEN, re-design your pipeline to eliminate the stresses, reduce them to less than acceptable margins.

ONLY THEN, allow an expansion joint to accept (with very expensive costs!) to accept the motion that you otherwise cannot accept.