Urgent help please!!!

[help7]

hello!
can someone help me how to restrain a pneumatic cylinder? It's a cylinder which will have internal pressure and end-plates... right now i'm just modeling the cylinder with no end plates so that i may verify the hoop and axial stresses....but how do i restrain my ends if i want to analyze the WHOLE cylinder since it's not symmetrical.

thank you!!!

 

[EngAddict]

Not really a recommended post title there.

How are the ends attached in reality? That should guide you to set up suitable contacts. If you model them touching they will be automatically bonded by your global contact type.

 

[MikeHalloran]

What advice did you get when you posted that exact problem before? Did you do that?





Mike Halloran
Pembroke Pines, FL, USA

 

[help7]

The cylinder has end plates attached ... but I'm supposed to check my work by analazying the cylinder alone so that I can check that the hoop stress is twice as the axial when it has internal pressure .... so that I can move on to add the end plates and nozzles that it has in the middle of the cylinder.

I know how to get the hoop and axial stress by modeling a quarter of a cylinder, but since in reality the cylinder has nozzles, it makes the cylinder assymetrical....hence I would like to analyze the whole cylinder with internal pressure...but I'm not sure how to restrain the ends, because if I fix both ends, my axial is way more than my hoop stress....I also tried using fixtures for "cylindrical surface" or something like that...and I played aroudn selecting and unselecting the "Translations" part....but I still did not get a reliable answer.

 

[EngAddict]

I believe you are not allowed to post requests for help with school projects here.

Go through the help files. You are on the right track though, just don't fix both ends. Maybe look up pressure thrust.

 

[help7]

this is not for school we just need some help to figure out this SolidWorks fixtures

 

[EngAddict]

... but I'm supposed to check my work by analazying the cylinder alone so that I can check that the hoop stress is twice as the axial when it has internal pressure ....

Sounds like a school project, not an industry check. If I am running a check I will compare PD/2t with the hoop stress from FEA and also check with displacement formula. That is enough to ensure my loads are accurate. You check boundary conditions by making sure your reactions or contacts is the same as your applied load. Of course you need to be able to work out which restraints represent your desired analysis..

But none of this has anything to do with SolidWorks fixtures, it is just basic FEA.