Good morning.
I have to model a line supported by Hilti pipe rings.
http://www.hilti.com/holcom/page/module/product/prca_catnavigation.jsf?lang=en&nodeId=-14399
The rings are insulated with gum, so the contact between support and line occurs on the gum. The rings can't move because they are fixed by a short threaded rod to a steel profile.
I would model the support by a X and Y restraint with a friction coefficient = 0.7
What would you do?
Thank you very much

Hi Chakot,

Generally Hilti rings are of just like pipe clamps.Support can be modelled in CII as Y & X restraint with a gap if required to act as a guide.

For steel to steel, normally friction coefficient is taken as 0.3.On what basis the foresaid value is used.

Hope clarifies you

Thank you Sathishnive, I guess that the friction between gum and steel is higher than 0.3, expecially because the clamp is well thightened on the pipe. There is no gap in my clamps.
Any contribution is very appreciated;

Is any particular reason you calculate these lines with Caesar?

These supports are for cold lines.

Remember that you can consider only the disadvantages of friction.

Regards,

Dear ALL,

my model is consists of partial underground pipe of only a 5meter. i feel that first support from buried line to be a fixed support. the rest of the pipe supports are sliding between steel to steel with friction of coefficient of 0.3 and sliding between teflon to teflon with friction coefficient of 0.1.

my question is how to give input in CaesarII for fixed support ?
is it +Y without any friction or Y without any friction or Y & X without friction and gap?

please advise

Thanks & Regards

Baskar

We could be discussing terminology here ...

Assuming the "Y" axis is vertical, then:

- To me a fixed support is an anchor.
- If you pipe is just sitting on a support, that would be a +Y (specification of friction is optional).
- If the pipe is on a support and cannot move up or down, that would be a Y support (specification of friction is optional.

Friction acts in a plane perpendicular to the support, so for example, the +Y above would incur reactions in the X and Z directions if friction is applied.