Pipe Shoe Modelling

Question

Hi, 
 
 Can I please have advice on what is the proper way to model the pipe shoe below and to determine the load on the support? 
 The pipe shoe will be used as guide/rest and line stop. So, the loads acting on are quite critical to determine the support is acceptable.

At the moment this is what I've done: 
 1. Added "rigid option" between point- with thermal expansion ticked. 
 For Guides: 
 
 Guide support on both end.(left and right gap-3mm), 2xEA will be install on both sides. 
 
 For Clamp/Line Stop:: 
 
 Guide support on both end (left and right gap-0mm). 
 Line stop support on both end

However, when I do that, the loads on line stop and guides seems to be unrealistic due to there are two line stop and guides acting on side by side.

Any advice on the right way of doing these? Thanks.

Mike Dattilio · Accepted Answer

Greetings, 
 At this time, you are not modeling in the structure steel. Therefore, your current approach appears to somewhat valid: 
 
 A set of guide supports, yes 
 Suggest to confirm guide support settings (gaps , friction factor, etc..) 
 Not sure that rigid pipe properties are needed as it is the carrier pipe between the supports. The only reason to model rigid properties is if you assume the pipe between the clamps to have a material where the elastic modulus will be increased by a rigid stiffness factor (typically 1000). The rigid stiffness factor can be modified by selecting Tools > Model Options > Edit Options. Otherwise, model as regular pipe. 
 If the clamps are so tight that they will resist any movement of the pipe through the support, then model with a higher fiction factor or model a single line stop. 
 
 Regards, Mike Dattilio Design Analysis Engineering Group Senior Analyst Bentley Systems Inc =============================================================================

Maciej Rydlewicz - CS Softdesk · Answer

Hi, 
 I like the direction you go with modelling. 
 1. No need to set rigid pipe - Mike described why. 
 2. If clamps are tight no movement is possible, so the friction factor does not matter unless you know the force acting on the pipe from the clamp... so I advise to... 
 3. Add a stiff line stop instead. 
 All three supports combined reflect the expected behaviour of this type of support. We should be able to build support assemblies in AutoPIPE to reflect in the model realistically what we have in piping systems. However, this option is not available in the program. So far we have to 'sculpt'. 
 4. Add steel member below - make it stiff. 
 5. Connect all 3 AP supports to one end of this member 
 6. Another end should anchored. If you want to let it move horizontally - modify anchor data. 
 7. If you need to take into account - add a short pipe (stiff, zero weight) instead of an anchor. Then Add V-stop to the second end of the pipe with a friction factor appropriate (e.g. 0.3?). Or another AutoPIPE support. 
 Remember that details are essential and the method mentioned above may or may not be appropriate to your case and requires testing. 
 You may have a combined structure loading/support reaction ready to use as a result of summing up force in V-stop. 
 If you are to fix the foot to the secondary support - instead of V-stop insert an Anchor. I believe you know what to do next... :-)

Pipe Shoe Modelling

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