Difference between tied contact and tie constraints

General Questions
1

Good morning,

I’m working on a simple project of a hub+shaft. PrePoMax gives two options:
1- Constraints–>Tie–>Selection of master/slave surface (the surfaces of hub and shaft in contact).
2- Surface Interactions → Tied → Contact Pair → Selection of surface interaction → Selection of master/slave surface.

What’s the difference between these two type of link?

I would also know, with reference to the option 2 above, the difference between the “node to surface” and “surface to surface” method in “contact pairs”.

Thank you.

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2

Tie constraint eliminates degrees of freedom while tied contact uses the contact algorithm and thus can result in longer analysis time. In most cases they can be used interchangeably but there are exceptions: https://youtu.be/Kc9Ln8zn3PE

Those are different contact formulations. They are comprehensively described in Abaqus documentation. In short words, surface to surface formulation represents contact stresses more accurately and has several other advantages over the node to surface formulation. Thus, it’s advised to use surface to surface contact in most cases.

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3

constraint has sensitive with mesh of both surface and master/slave definitions, tied is not.

4

If your connection between parts is tied, you can also merge the geometry of the parts to create one part with a coincident mesh. You can use a compound part inside PrePoMax to do so.

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