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Inventor simulation contacts explanation - non video

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Message 1 of 9
mantena.engineering
1600 Views, 8 Replies

Inventor simulation contacts explanation - non video

Hi

 

I struggle to find an explanation on the contacts in simulation. I have the **** simulation 2010 book but it does not even mention anything. I need this so hard as i keep getting random soft spring attached somewhere and i do not accept that.

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Message 2 of 9

Attach your file(s) here.

It sounds like you are missing a constraint (which might be perfectly acceptable - the reason for the soft spring).


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Message 3 of 9

I just want a paper with an explanation of the different contact options. I have no paper or pdf with explanations.

Message 4 of 9

Hi Matso,

 

The way contacts work is they have a normal and tangential stiffness with respect to the face pair.  Each contact type takes advantage of different combinations of these stiffnesses and directions.  You can think of the contact having many small springs connecting the two faces.  The 'sliding' is analagous to the tangential direction(s), and 'separation' to the normal direction.

 

A bonded type has “infinite” stiffness between the mating faces in both normal and tangential directions. 

 

The separation contact has zero stiffness between the faces in the tangential direction (allows sliding).  It doesn’t allow penetration, but allows separation.  Therefore, it has an infinite stiffness in the “inward” normal direction and zero stiffness in the “outward” normal direction.

 

Sliding  / No Separation has zero tangential stiffness, but infinite stiffness in both inward and outward normal directions.

 

Separation / No Sliding has an infinite stiffness in the inward normal direction, and zero stiffness in the outward normal direction, with an infinite stiffness in the tangential direction.

 

Hope this helps!

 

Best regards,

-Hugh



Hugh Henderson
QA Engineer (Fusion Simulation)
Message 5 of 9

Hi

 

Have a look at MG13520-4 i still get soft spring added.. I have bonded contact on bolt to nut. Everything else is separation.

https://dl.dropboxusercontent.com/u/72823890/Jobb/MG13520.zip

Message 6 of 9

Hi matso,

 

  The with separation contacts, the bolted connection is still able to rotate with respect to the plate and square tube.  This is why we get the soft spring message.  From an FEA solver standpoint, it has an open DOF that needs to be 'locked out' by a soft spring in order to solve the equations.

 

Best regards,

-Hugh



Hugh Henderson
QA Engineer (Fusion Simulation)
Message 7 of 9

What is DOF?

Message 8 of 9

Degree of Freedom


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Message 9 of 9
AMIRHOSSEINGMI
in reply to: henderh

Hello
What is the meaning of infinite stiffness? for example, when we wanna define a spring contact and we have infinite value in either tangential or normal, what magnitude should be written in the blank fields?

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