Problem with creating surface by 'comp' command in CGX

1

Hi there,

My intention was going to apply a 3D bolt pretension by a surface and a node. I partitioned a cylinder by a plane in Salome and made a face group of the interface ‘pret’ and a bottom face of cylinder ‘bot’. Then I exported the mesh as unv file and coverted to inp file.

In cgx, I used ‘comp nodeset do’ and ‘send nodeset abq surf’ to export surfaces. I succeeded with the ‘bot’ surface, as shown below, however, in pret.surf file, the element faces was empty. I don’t know why, probably due to partition? How could I create such a surface for bolt pretension? Thanks in advance.

image

Best regards,
William

2

Hello,
maybe you can post what is in your set pret,
if you ask with prnt se !?
than we can have a look ?
maybe there is something missing in your set ?
wbr

3

Hi Dichtstoff,

Thanks for your reply.

I can see from cgx help document for command send that it probably doesn’t work for such an internal face due to partition operation. But then could it be possible by other command/approach if I am going to generate such a surface to apply pretension card?

send top abq sur
will write the elements in set top together with the face-nr (Important: Only
free surfaces of the mesh are regarded, internal faces are unknown and can not
be identified).

I attached my prnt se for your information.

internal_face
internal_face1193×623 65.3 KB

BR, William

4

Hello ,

i don’t see no reason why it should not work with both sets.
but for better understand i recommend you always to have a look
on your sets after each command!
where you get the (surf)faces? from the elements in your set !?
you have to fill your set with elements (from nodes) and from elements you
get the (surf)faces !?. Maybe you have to use the commands often (twice)
or you have to use comp set up !?
you have to play a little bit and check always
with prnt se and plot f bot

wbr

wbr

5

Hello William,
you identified the problem correctly. Unfortunately cgx does not create internal element faces and can not deal with them. I see only the possibility to create a set of the relevant elements. Then write this elements with the send command to the filesystem (send set frd c)and open this file again in a second cgx session. There you create a set of the now visible faces (qadd set t1) and export them in the usual way.

Best regards,
Klaus

1 Like
6

Thank you very much Klaus, finally I got succeeded according to your suggestion.

hcpy_1
hcpy_1784×656 30.8 KB

7

In my analyzes, I divide the bolt into two parts A and B, then:

  1. create a mesh from part “A” ,
  2. send the surface,
  3. create a mesh from part “B”,
  4. and finally connect both meshes.

mesh S_A
COMP pre do
COMP pre do
SEND pre abq sur
mesh S_B
merg n Bolt
send abq Bolt

pre

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