Define bolt load with normal screws in Abaqus

[SommerK]

Hello together,

in my simulation I use bolts with nuts (simplified) and normal bolts with threads that are screwed in a hole. I don't get any error messages with the screws with nuts, but I don't know exactly how to interact the normal screws with thread. Do I have to create a tie constraint between the screw shaft and the hole? I get the following error message afterwards:

-72 nodes may not be used with a multi-point constraint since they are also part of pretension section. The nodes have been identified in node set ErrNodeMPCPretenSec.

I have a suspicion that there is a problem with the condition of the tie-constraint interacting with the preload of the bolts and thus there is a double interaction. I have now set the surface for the preload of the screw further in the direction of the screw head so that the tie-constraint and the preload of the screw do not overlap. Is this the right way to go? Does anyone know this problem and maybe has a tip for me?

Thank you for your efforts!

 

[FEA way]

So the threads mentioned by you are not modeled ? Can you share a screnshot showing the bolt and the part (or parts) to which the bolt needs to be connected ? Tie constraints are sometimes used between the head/nut and the surfaces of connected parts but not between the bolt shaft and inner surfaces of the holes. There you typically have some clearance and contact defined if needed.

 

[SommerK]

Hello FEA way,

thank you for your quick respond. Yes, the threads were not modeled because I wanted to do a simplified calculation.

Here is the screenshot.

Unfortunately, I didn't find anything about it in the forum, where only the connection between a screw and a nut is discussed.

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