Flanges - Axial Force and Bending Moments

[RandomAxe]

What is the best way to extract loads at flanges? I have modelled all flanges as rigids with an anchor and cnode, a technique I read about on here. I want to confirm that I am interpreting the results correctly. If I have a section of pipe along the +ve X axis, say 10m length with nodes 10 to 100 and a flanged connection at nodes 40-50 (rigid) and 51 to 55 (rigid). So I have an anchor at node 50 with cnode to 51. The piping then continues along the +ve X axis. This then allows easier viewing of the flange loads via the restraints summary (global). The restraints summary reports the loads on the restraints, so looking at the restraint summary for node 50, if Fx = -100kN, am I correct in interpreting this as being in compression?

 

[saplanti]

It depends. If it is in the TO node yes. If it is in the FROM node it is in tension.
Why do not use the FLANGE CHECK option to see the equivalent stress check? This will summarise the flange loading as well as preliminary check for you.
The best is to share your C2 file with the community, they may answer better. I do not have CAESAR II with me.

 

[RandomAxe]

Thanks for the response. So if the anchor is on the 'TO' node then it is compression? That is how I have modelled it.
Do you know whether these forces include the end cap pressure force (as well as thermal)? Yes that is how I usually check flanges but I'm working on a project with custom non standard flanges and the client is requesting the axial forces and bending moments for each flange....
Thanks

 

[RandomAxe]

I have bourdon effects on (translation only).

 

[saplanti]

As I explained you need to provide the model for the discussion. However I cannot comment on it since I do not have CAESAR II with me.
My comment on the forces on the element forces only. It is not related to the support forces. You'd better model model the flange check and get forces on the flange itself if your interest is flange only. However your interest is the force on the anchor, you'd better get the forced from the restraint summary.

I see that you do not have sufficient experience on the modelling and getting the right information from the model. Either share the model with others with your target information that you need or find someone close to you that can answer/advice you what to do. Unfortunately, we cannot easily figure out what exactly you are after and the way you are working.

 

[RandomAxe]

OK thanks, I will get the model when I'm at my office tomorrow. I will provide an overview for information. I am modelling a subsea spoolpiece (well several sets) to be installed between a manifold and a PLET. It is essential an L-spool (75m straight, 20m offset), and I have modelled the seabed friction with X2,Y2,Z2 restraints. I have modelled the flanged connections at the structure tie-ins as described in my original post, and I want to determine flange loads at the interface both to check the flanges and to pass to the structural engineer designing the manifold and the PLET (note that there is a welded anchor support 1.2m inboard of the tie-in, where the models are terminated). I have ran the model for operating conditions (P+T+WAV1 etc) and planned to check the flange/tie-in loads via the restraint summary, and I was looking to confirm this approach was OK. Thanks again