Jump to content

Optistruct - No Separation contact simulation

Recommended Posts

Dear all,


I'd like to ask you for help regarding specific contact simulation.
Please have a look at the sketch below (I know that this particular case can be easily calculated analytically :) ).


There is a L-shape profile (on the right) which is screwed in to a flange on the left.
There are two types of connection:

  • Pin connection - pins transmit shearing load (red)
  • Bolted joints which ensure flanges integrity (blue)


There is also a contact plane marked in yellow.




I have modeled pins explicitly with merged nodes between flanges as shown on the figure below.



My question is how to model the contact between blue and dark yellow elements?
Ideally it would be kind of no separation contact so both surfaces remain fixed but no shear load is transmitted.
I want the pins to carry all shear load and I'm not interested in the bolts assessment.


There is a nice presentation about optistruct contact settings - Optistruct Contacts.pdf

And even contact type "NOSEP" is described but I can't find it in my v13.


Could you please give me any advice?

Thank you in advance.




Share this post

Link to post
Share on other sites

Hi Jakubat,

if you use no separation contact, once the contact pair comes into contact, they can slide against each other without friction as you can read in the Optistruct Contacts.pdf  file page 20. So if you use "no separation" contact shear load can be transmitted, it depend only on your loading condition (see page 23).

 If you want  both surfaces remain fixed but no shear load is transmitted use FREEZE contact so that you will only transmit tension and compression. 

Have a look on this : 


Share this post

Link to post
Share on other sites


Thank you for your advice. 
I slightly disagree with the last statement - FREEZE contact type transmits all kinds of loads/motions as its described in the help and the post you  mentioned. 
If I use FREEZE type in my case there will be no point in modeling the bolts and pins. Glued surfaces are bonded and pins will not see any load at all.
Just for confirmation - I'm speaking about vertical loads right now (vertical force/dead weight) 



This means basically, that the two contact surfaces are "glued" and will transfer all loads / motions between master and slave (also known as Tied Contact).

My initial idea was to replace only the screws by the "NOSEP" contact type. Just wanted to save time :)
The problem is that I currently don't see any way to insert NOSEP contact in HyperMesh (Optistruct profile)

Share this post

Link to post
Share on other sites

Hi jakubat,

sorry for the misunderstanding, my advice was about the contact between  blue and dark yellow elements not about modeling  the pin and bolted :


And i was thinking initially that you have 2 bolted joints (red and blue) instead of pin and bolted here : 



Share this post

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

You are posting as a guest. If you have an account, please sign in.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...