I have a piping model with support members included. The model includes the cut short function to create a prestress in the system. When I open the LOAD/STATIC ANALYSIS SETS/MODIFY STATIC ANALYSIS LOAD CASES dialog, there is a tick-box to indicate Cut-short analysis. After editing the dialog box, including ticking the Cut-short analysis box, the dialog is closed. When opened again, the Cut-short tick box is shown as not ticked?
Is this a bug, or is there possibly something else that must be done to activate the Cut-short analysis?
This is an expected behavior.
Cut short should not be added to code stresses. It should only be applied to non-code combinations ( such as support or anchor reactions) cases. You would need to have two separate analyses, one with cut short for support results and another without for code stress especially when cut short is added to GR case. If you add it to U1 case, you may be able to do that in one analysis, but still you would need to click every time on the checkbox.
When cut short is added to U1 case then you can delete Sus+U1 case and the code cases will not be affected by cut short. AutoPIPE will generate non-code combinations
and these will have cut short applied to cold GR and hot GR+T1 cases.
I agree this is an odd behavior and we may change it in the future.
Thanks. That clears up some of the confusion.
I was trying to rig this model with a cable suspension structure to provide support to a long span of pipe, so I wanted a way to preload the support cables. Sounds like I'll have to find another way to do that since it needs to be included in all the cases for code stresses as well as support reactions.
I just wanted to point out that AutoPIPE results are valid for small displacements. Also, although AutoPIPE takes into account pressure stiffening of bends, it does not take into account tension stiffening of pipes. When you have catenary structure, these are important factors to consider.