Modelling friction at supports during dynamic analysis of piping systems (Caesar II)

[nipra03]

I would like to receive feedback about the benefits of including friction of supports in dynamic analysis - from analysts experienced in this.

A view I have heard is that including a factor for damping is sufficient and hence you do not need to include for friction while doing dynamic analysis.

My issue is that for large diamter piping (> 24" dia.) the friction force (assuming coefficient of 0.3) at the supports can be quite significant in magnitude and should be significant in reducing the dynamic forces and DLF (dynamic load factor)in say a Response spectrum analysis for a hydraulic hammer case.

hoping for a quick feedback.

 

[DSB123]

IMHO forget about friction in a dynamic sense especially if the dynamic loads include vertical loads. You never know when the support is actually in contact with the support or guide and what normal force is applicable between pipe and support steel. The results will be meaningless and no-where near the reality. It's bad enough trying to apply friction for the normal thermal/operational load cases due to not knowing the exact load distribution on the supports (due to fabrication tolerances and pipe tolerances)

 

[RandomAxe]

It's a linear analysis so gaps and friction are ignored.