Hi MoverZ
Yes I could have mention that load , movement relation applicable for variable spring only. constant spring as it state always constant load.

Regarding "realistic representation" I like to say realistic approximation representation.

Caesar default do not consider bourdon effect, does not mean that effect is not present there for metallic piping, I like to consider it under approximation.

Code (B31.1/B31.3) ask Appendix D note-7 for Large bore thin wall thickness pipe , but I think Caesar consider it irrespective of pipe OD & thickness. I don't see we need to be very serious of it.

I have asked to set "Pressure Stiffening" -"No" just to cross check how variation of load came into picture, not to apply in real analysis.


Even if somebody use that, still can argue for pipe diameter & thickness limit because Code has not specify clearly the limit.
I already cross check, it is not going to create huge error in calculation.

You are right to say we should not "finding ways to hide or ignore effects." but still can go for realistic approximation , as long as we understand what assumption we are considering & what could the possible impact.