Slip Joint

I modelled the slip joint as like what mentioned in the application Guide, but the results are totally different...is the model shown in th application guide is right ?...and also there is not a clear idea how to model..plz can any one suggest how to model the slip joint in CII...is it correct to model like a axial expasion joint instead of slip joint..

The slip joint is simply two co-located nodes (in the center of the joint) that are restrained together in all degrees of freedom except torsion, usually rigidly, except for the axial direction which contains a finite stiffness representing the packing resistance to movement. For example, suppose my pipe is running in the X-direction and I have my slip joint on one pipe node 100 and adjacent pipe node 101. You would then have:

X2, Y, Z, RY, and RZ restraints at node 100 with Cnode 101. Only the X2 restraint would have a stiffness K1, a breakaway force Fy, and a low stiffness K2. All other restraints can be modeled as rigid.

thnx brown, but i didn't get it what exactly you are saying. So can u send me the slip joint modelled file, it will be easy for me. My id is krish_arunachalam@yahoo.co.in

Attached is a very simple slip joint model. There is overlapping pipe of 500 mm in this one, representing one pipe slipping inside the other with packing material between them. The pipe runs in the X-direction, so we have restraints on Node 30 with Cnode 50 including Y, Z, Ry, X2 (with stiffness and breakaway force), and Rz (defined on element 40-50 because no room on this spreadsheet). Run this file and look at the output and you will see that there is relative axial movement between nodes 30 and 50. No other relative movement is seen. Then look at the same file with the slip joint removed. Especially review the axial forces on the anchors in these two files. I am not claiming the numbers I used for this are representative, just illustrating an example of how to model the slip joint.

Brown i couln't download the file..think there is problem in downloading.

I have sent it to you in e-mail.

is it possible to send me this files??

my email is: kacperekj@o2.pl

Thank you very much,

Regards,
JK

But, Loren, for the slip Joint should have the pressure force added, I don' think you take this into consideration! why?

Mr. L. Brown,

Brown i couln't download the file. There is problem in downloading.
Is it possible to send me this files?

My email is osvaldo.tadeu@ajato.com.br

Thank you.