Richard and Fellows,
Could you please share your opinion what is the Nonadvantages and limitations if we modelling the trunnion w/shoe on vertical pipe as you see in attachment?

It is up to you how detailed do you need / want to be your analysis.

For non critical situation, your model should be enough. If you are afraid that the real location of the support have a large influence on the results, then go ahead and add the trunnion. Compare the results and you will understand.

Sometimes, on critical systems, you may need to rotate the trunnion (90 deg, 180 deg)or to have a longer or shorter trunnion in order to reach acceptable results but this yu can not know until you actually model the trunnion.


Regards,

thanks Danb.
But i think when we modeled like above, we can't see the real situation in the junction of Pipe and the Trunnion.
If only for Local stress of the trunnion or the pipe shoe, we can calculate that using Kellogg method, and for the trunnion flexibility we also have our own company spreadsheet to calculate that. i'm only concern aboutthe stress at the junction of the pipe and trunnion.
once again Thanks.

It is not only for this, believe me. Sometimes the location of the support is very important, and have influence on results (e.g moment arm, a trunnion that rotate...)

Regards,

Yes danb, and in my case above you also see that it is below the Relief Valve (Closed) system, i also concern when the RV Pop Up at the first time then it will give jet force down and the Trunnion w/ shoe will experienced an axial load from this effect (in the PDMS model i don't shoe the beam that supported the Trunnion and pipe shoe).

At POP up, the forces will be one up and other backward (people that live in Northern Europe knows what I'm talking about ) so you may need a hold down.

Regards,

Yes i agree.....

As you see in the pipe shoe there is a Hold down Guide...

I can't see very well this on the 3d model(I was thinking that is a normal guide, an angle), but if is a hold down guide is good.

Regards,