stiffness data for expansion bellows on pipe stress analysis 1

[rudiawan .]

friends..
i am doing pipe stress analysis, and having expansion bellows on the piping.
How to input the axial stiffness, bending stiffness, torsional stiffness on the pipe stress analysis software.
on the vendor catalog, it doesn't have it




regards
rudiawan

 

[1503-44]

0, 0, 0

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Ask the vendor or look at your data sheet.

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

 

[RVAmeche]

Vendor catalog values are just a starting point. Give your vendor the service/size/movements required and they'll give you stiffness values. Then you put those in the model and make sure your equipment loads and restraint forces and pipe stresses are still okay. You may need to iterate.

 

[1503-44]

I said 0,0,0 because you do not want pipe stress load on a bellows.
So, a bellows should not restrain the pipe in any way.
You need to allow the pipe to expand fully, so there are no restraint loads put on the bellows.
You ensure there is no rotation, from axial bending, or torque.
You may need to install axial guides on both sides of the bellows to ensure that there is no axial offset deflections that would introduce bending. The guides go on the pipe.
Only a small amount of axial displacement is acceptable.
Then you fit the bellows to the pipe.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."