Hi,
I've been trying to apply moments, and forces to a vertical vessel, but M(y) is grayed out. I've tried it on a head, and on a shell as well but it's grayed out on both of them.
How can I apply M(y)? Please help.

Thank you.

Istvan

Could you be a bit more specific, what exactly moments you are trying to apply;- wind loads, seimic loads, external nozzle loads? Are you sizing the skirt?
cheers,

Hi,
I've got nozzle loads on the nozzles, but as far as I know PVElite doesn't transfer them to the support, so I can't check the support for those load. Usually I don't do this whole thing, but this time it was a client requirement.
So there is a Force/Moment Dialog which can be accessed using the icon with 2 arrows on it, and I used that to model all the loads on the vessel. All I could do is to apply those load in the centerline.
In that dialog there are 6 fields to fill out for 3 forces and 3 moments, but M(y) is grayed out. So I can't enter all 3 forces, and 3 moments which act on the nozzle.
I'm trying to size legs, but maybe I'll have to change it to a skirt.
I hope it's clear now, and you (or anyone) can help.
Thanks
Istvan

Hi Istvan,

The loads on the Force/Moment dialog act all across the vessel crossection. In our coordinate system "Y" is up. A moment about the Y axis would produce torsion on the vessel cross-section. An entry of My is not allowed because there is no torsional stress calculation performed. In a typical vertical vessel this effect can be ignored as the resulting stresses are very small.

If that is not the case in your model, then you should be careful and consider it separately.

I have a similar issue but on a horizontal vessel, the program only allows input of forces & will not allow moments to be added(moments greyed out).
How can moments be applied to a horizontal vessel?

kdunks,

Read the notes on the Force/Moment dialog. Work out the force to generate the moment required at your given offset.