How to apply Coupling Constrain, and Rotation of 3D Model? 1

[bhavbhuti302]

Hello Abaqus Users,

I am very new to Abaqus, and trying to rotate one gear related to other. When I try using the normal cylindrical constrain, I found that it rotates but it also expands the model. So, is there anyway I can rotate the model and other model rotates with that. Also, I feel that coupling constrain can actually help me, but I don't know how to apply coupling constrain. I tried using the abaqus manual but it's not too clear to me. Can anyone please help me to sort this problem out. I will appreciate if someone can upload very simple file having coupling constrain in it.

Thank you
Bhav

 

[rstupplebeen]

Check out OptiEng's topics. I helped him with a similar problem with rotating disks in edge contact. Start with his oldest posts and work forward. I hope this helps.

Rob Stupplebeen

 

[bhavbhuti302]

I really don't understand when you have explained about the coupling thing. And I think he didn't reply back after your answer so I am sure what he has done. Can you please explain me bit more about the same rotation. I am having similar rotation and trying to find contact stresses in the gear tooth. Thanks in advance.

 

[OptiEng]

Hi bhavbhuti302,

I hope I can help on this, I have conducted a similar problem, expect one of my surfaces is a rotating analytical rigid surface and the other is pad with a pressure applied to one side, see the cae file attached. Please take a look to see if this helps and we can discuss.

Kind Regards

 

[bhavbhuti302]

Hi OptiEng

I really appreciate for your file sharing, it gave me some hint, but I have both 3D models to rotate with respect to one another. I have 2 gear models to rotate as one is driver and other is driven and want to analyse the contact pattern of the tooth surface.

I will still try to use this trick, but I wonder if it works for 3D. Can you please help me for 3d models.

Thank you for reply.

Please check out the file attached. (I just usded normal boundary conditions, I am sorry but it takes ages to solve the analysis. I can attach .odb file if you want.) Can we talk on some messanger about this. Thank you.

 

[rstupplebeen]

I would create a reference point at the center of rotation of each gear. Tie all DOFs of the inner surfaces of the gear to these points. Constrain all DOFs of the reference points except for the rotation on the axis. Apply a torque to the one reference point. You probably need to define some more contact surfaces in your contact definition. Define all potential surfaces otherwise penetration could occur. I hope this helps.

Rob Stupplebeen

 

[bhavbhuti302]

Thank you Rob,

But when I use tie constraint, it asks me to define Master surface and slave surface, do I need to select my interacted master and slave surface or the RP that I have defined for this feature. I selected RP as master and all the nodes as slave in Tie constraint. I have some warnings like 1 node is not tied because it is out side the distance tolerance.

Bhav

 

[rstupplebeen]

Sorry I meant coupled. See attached image.

Rob Stupplebeen

 

[bhavbhuti302]

Thank you Rob,

I actually tried the same way, and now trying to see how coupling constraint works and i found really weird results on this simple ring. Please check this file I am uploading, I simply give rotation and coupling constrain, and in analysis result if you magnify it, and see the deformed and undeformed shape together then you will see it is getting expanded. I am not sure this should be the result. Can you please check this for me.

Thanks a lot...
Bhav

 

[bhavbhuti302]

See this is how it looks like after rotating with 11X magnification. I presume that the magnification should magnify deformed and undeformed shape and not just undeformed.
Also it does not give rotation step wise but gives all at once. I think I am missing something at this stage.

Thank you

 

[mosab2]

Hello Abaqus Users,

I am trying to rotate one disc (Elstic material) related to other (the same material) in 2D. When I put angular velocity (U6), I found that it rotates but it also expands the model. I was reading all messages and i did everything but in 2D but nothing, any one can help me? or have an example with file.inp?

Thank you

Mosab2

 

[bhavbhuti302]

Hi Mosab2,

I dont know if it is bug or if we are doing something wrong, but its frustrating how magnification shows expanded model. I hope someone has clue for us. Finger Crossed.

 

[mosab2]

Hi bhavbhuti302:

I don´t know why.. but really it is a little bit rare.

I will wait, becuase i don´t know what can i do..

Finger Crossed.

Thanx

 

[mosab2]

Hi bhavbhuti302:

can you send me all files but in version 6.5 o 6.7
Becuase i can not open them,

Thank you

 

[bhavbhuti302]

Well actually I dont have older version, and I can't create old version files, I am afraid. But as long as I know, I tried all possible way that I know, but nothing worked so far. All I see is expanded thing after rotation. I never tried Explicit though, I am not sure it is a good idea in that, and I don't know how to work on that either. So, again I will wait for some more time as you said.

Good luck.

Bhavbhuti

 

[amubashar]

bhavbhuti302:

I have done some modifications in your rotation.cae file and it seems to be working fine now.

 

[bhavbhuti302]

Hi amubashar,

Thank you for your effort and suggestion, It looks perfact in the 1:1 sale, but further magnification shows the expanded view, I am not too sure if it has to be like that, and also the value of U(displacement) also changes with the iterations of the step. So I am not too sure if it has to be like that, but 1:1 looks perfect though.

I will try to do that same thing on my gear model and see if it works or not. Do you have any suggestion for, if I have to rotate two gears one related to other, how can correlate them?

I really appreciate for your help.

Regards,

 

[amubashar]

If a deformation scale factor greater than one is applied, the deformed shape would look like its increased in diameter compared to the original geometry. If you measure the diameter between any two points on the disk, it remains same before and after deformation (the base distance and the deformed distance unscaled).

I don't really understand what you mean by "if I have to rotate two gears one related to other, how can correlate them?"

 

[bhavbhuti302]

Hi Amubashar,

Please check the attached file, in that, I have fixed the gear to find out the stress at contact, but I am thinking to give rotation to both instead of just pinion. In first step they just come into contact, and then I applied the torque. But instead of fixing the gear in all step, is that possible to make it rotate with the help of torque that we apply on pinion.

I hope it make sense now.

please see the attached file.

Thank you for your help and interest.

Regards,
Bhav

 

[mosab2]

Dear bhavbhuti302 and Amubashar

Can yyou send me the file not in .cae sino in .inp
so i can see how you did it.

Thank you