AnsweredAssumed Answered

no penetration contact not taken into account

Question asked by Adi Pro on Jun 13, 2016
Latest reply on Jun 15, 2016 by Jim Riddell

Like • Show 0 Likes0
Comment • 4

Hello visitors,

There is an assembly composed of: a structure (1, see image) which is supported by four fixed parts (2). Contacts structure/support are

No Penetration Contact.

My goal is to observe the flextion of the structure (1).

The problem is that one of four contacts is not taken into account (there is a lack o support, a side of the structure is not supported => the stress is very low on this support) consequently there is an anormally high stress and torque on the opposite support (which is not normal).

Do you know:

1 why this contact fails?

2 and how to correct this failing contact?

thank you in advance for your ideas

P.S. I use Slidworks 2013

Adi Pro Jun 15, 2016 6:03 AM

Correct Answer

Hello James,

Your idea to study the reaction force it'is a good way to identify where the problem comes from. However I succeed to run the model in a different way:by replacing two supports by an unique support (cf picture BEFORE/AFTER)

By the way, the solver nocticed several times the message "Star stoped working" without explanation. I had to restart the PC and run the study: it worked.

Thank you for your suggestions

See the reply in context

No one else had this question

Outcomes

Jim Riddell Jun 13, 2016 4:05 PM

If you have set up the support points as non-penetration (doesn't look like an issue) and the structure deforms in such a way as to 'lift off' one of the points then there will be no stress in that area.

Depending on exact geometry, your 4th support may be holding the structure down (negative force) if they are rigidly attached in any way.

Actions

Jim Riddell @ Jim Riddell on Jun 14, 2016 6:02 AM

In order to verify the above, try fixing the contact surfaces (leaving off the off mating parts) then check the reaction forces on those surfaces and verify that the resultants are heading in the direction(s) you expect to see.

Actions

Adi Pro @ Jim Riddell on Jun 15, 2016 6:03 AM

Hello James,

By the way, the solver nocticed several times the message "Star stoped working" without explanation. I had to restart the PC and run the study: it worked.

Thank you for your suggestions

Actions

Jim Riddell @ Adi Pro on Jun 15, 2016 6:13 AM

Sometimes "Star" gets confused. As long as your results look reasonable that's what matters. It is always a good idea to do a FBD and hand calculation to check.

Actions

4 Replies

Jim Riddell Jun 13, 2016 4:05 PM
Mark Correct
Correct Answer
If you have set up the support points as non-penetration (doesn't look like an issue) and the structure deforms in such a way as to 'lift off' one of the points then there will be no stress in that area.

Depending on exact geometry, your 4th support may be holding the structure down (negative force) if they are rigidly attached in any way.
Like • Show 0 Likes0
Actions
- Jim Riddell @ Jim Riddell on Jun 14, 2016 6:02 AM
  Mark Correct
  Correct Answer
  In order to verify the above, try fixing the contact surfaces (leaving off the off mating parts) then check the reaction forces on those surfaces and verify that the resultants are heading in the direction(s) you expect to see.
  Like • Show 0 Likes0
  Actions
  - Adi Pro @ Jim Riddell on Jun 15, 2016 6:03 AM
    Unmark Correct
    Correct Answer
    Hello James,
    
    Your idea to study the reaction force it'is a good way to identify where the problem comes from. However I succeed to run the model in a different way:by replacing two supports by an unique support (cf picture BEFORE/AFTER)
    
    By the way, the solver nocticed several times the message "Star stoped working" without explanation. I had to restart the PC and run the study: it worked.
    
    Thank you for your suggestions
    Like • Show 0 Likes0
    Actions
    - Jim Riddell @ Adi Pro on Jun 15, 2016 6:13 AM
      Mark Correct
      Correct Answer
      Sometimes "Star" gets confused. As long as your results look reasonable that's what matters. It is always a good idea to do a FBD and hand calculation to check.
      Like • Show 0 Likes0
      Actions

no penetration contact not taken into account

Outcomes

Related Content

Recommended Content