displacement below support

Posted by: vermaccio

displacement below support - 10/22/19 12:35 PM

I have a shoe support resting on something that moves, how can i set a displacement of this type? I don t need to put displacement on support node because shoe friction can limit the displacement. Maybe ican use a cnode on shoe/suport node and then the cnode is connected to a vertical pipe having the wished displacement?
Posted by: Michael_Fletcher

Re: displacement below support - 10/22/19 02:03 PM

You're not wrong, but I can also suggest the following:

Apply a CNODE to your support to a CNODE that is otherwise unused in the model.

Apply a displacement to the same element that contains the support.

Specify a displacement on the CNODE instead of either node that otherwise forms your element.
Posted by: vermaccio

Re: displacement below support - 10/22/19 03:44 PM

If i well understood:
I have pipe and node 10. At node 10 i have a shoe (+z support) having friction 0.3. In system there is no node 14. In node 10 i insert cnode 14. In node 10 i also insert displacement for node 14.

More, if i have many nodes where same displacement apply, i will insert in all nodes the cnode 14 but i will set displacement for node 14 only in one node (examoke node 10).
Posted by: vermaccio

Re: displacement below support - 10/23/19 01:10 AM

if i apply same cnode in two nodes , the line graphic "breaks" and the two node ends in the same point. so i have to set a different cnode for each node. where is the problem? i am using caesar 2016.
Posted by: Sigma

Re: displacement below support - 10/23/19 02:38 AM

This may be because Connect Geometry Through CNodes in configuration file is set True.
IMHO for multiple restraints having such displacements, it is better to have different CNodes and apply displacements through CNodes. I hope the parent line is large enough and not influenced by the reactions from the line under consideration.
Posted by: Michael_Fletcher

Re: displacement below support - 10/24/19 09:52 AM

Offhandedly, I couldn't say either what would happen if you modeled your entire system to be CNODEd to the same node (e.g. 14) and turned off the connect geometry through cnodes option.

Thus I would concur with Sigma - you should CNODE all the supports and add a new node number for each one, and apply the displacement each time.

It's cases such as these that you will benefit from a node numbering plan.