Learning Forum

[guy-hermann.youdom-yimbi.1]

Hello everyone, I'm trying to create a rigid region by issuing the CERIG command. I've created components to easily select the independent and the dependent node.

I got a message saying that the independent node is not selected and the CERIG command is ignored. But when I checked my components, they contained the node they should contain.

Could we help me find the problem there.

 

I have another problem with my element selection using Real constant as a driver parameters.

When I issued

ESEL,s,REAL,,NB_1,NB_2,1

I got a different number of elements when I added

ESEL,R,TYPE,,nb_3,nb_4,1

But this type is only related to these real constant.

Thanks for helping me 

[dlooman]

Usually when this happens to me it's because the master node isn't selected.  In your two element selection commands one has ESEL,s and one has ESEL,R.  The 2nd command, a "reselect" won't give the same elements if they aren't all currently selected.

[guy-hermann.youdom-yimbi.1]

Does that means that I have to select that node before issuing the CERIG command?

By the way I have issued ALLSEL before the CERIG command.

For the selection problem, according to what I read on Ansys documentation the reselect command shouldn't change.

Is it possible that if we issue a reselect command with a result which doesn't change the set already selected we got problems?

Thanks 

[dlooman]

If you issued allsel before the cerig command how is it possible that the independent node wasn't selected!?  If you say there is a one to one correspondence between the element real constant set number and the element type numbers you specified, the only explanation is that the second one was a reselect.  Why didn't you use ESEL,s for the type numbers like you did for the real constant numbers?

[guy-hermann.youdom-yimbi.1]

There is no one to one correspondence between real constant and elements type. But when I selected just using the real constant I got a number of elements more than what I've expected. That's why I added the ESEL,R,Type,,, then I got the good number of elements in that case in my selection.

The problem is that all the elements with the real constant that I first selected just have the type I've applied into the reselect command. So I was expected to get the same number of elements.

For the CERIG command, yes I've applied the ALLSEL before and I got a warning message saying that the independent node is not selected. I don't understand why ... Is there any other resources that I could look to better understand the different functions in APDL other than the command reference book? Thanks 

[dlooman]

Just the ESEL command documentation.  You might have to use elist, rlist, etlist to debug it.  Can you share your complete CERIG command?

[guy-hermann.youdom-yimbi.1]

That's my CERIG command 

ALLSEL

CERIG,noeud_directeur_ext_1,noeud_conducteur_ext_1,all

Knowing that inside that components names I have the independent node and the dependent node. I've checked that

[dlooman]

I reproduced the issue with a test.  CERIG is an old command and apparently component names aren't supported.  You'll have do something like:

cmsel,s,noeud_directeur_ext        ! node nnnnn

cmsel,a,noeud_conducteur_ext

CERIG,nnnnn,all,all

[guy-hermann.youdom-yimbi.1]

I was sure something were not normal... Since I used that I've been through that kind of issue a lot 

Thank you

[guy-hermann.youdom-yimbi.1]

I tried to use the method that you have proposed but that doesn't work too.

It works only when the dependent node applies is the first one. If I put another number I got the same issue saying that the independent node is not selected.

Is there something else that I could try? Thanks in advance