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Axisymmetric torsion

Posted Dec 5, 2022, 1:41 p.m. EST Modeling Tools & Definitions, Results & Visualization, Structural Mechanics, Modeling Workflow, Material Models Version 6.0 4 Replies

Kimberling Sanchez
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Hello everyone, I want to ask you please some questions, some are maybe basic questions because I´m a beginner. I will briefly describe what I want to do and then I will ask the questions.

COMSOL 6.0

I want to carry out a wire drawing process (basically it is to reduce the diameter of a wire by passing it through a die) and I would like to make this model in 2D-Axisymmetric (it is an important requirement), therefore I obtain the drawn wire (which includes residual stresses) in 2D-Axisymmetric.

My objective is to carry out a torsion test on this model, therefore my questions are the following:

  1. Is there the possibility of applying the torsion moment in this 2D-Axisymmetric model, using the Axisymmetric torsion tool, by check the "Include the circumferential displacement" box, taking into account that I want to make large strains in the model?

  2. Is there the possibility of converting the 2D-Axisymmetric model (r,phi,z) into a 3D model (x,y,z) to be able to apply the torque there and carry out the 3D analysis?

Is there any other option that you can suggest me?

I thank you in advance for your attention and I will be very grateful to receive your answers.

4 Replies Last Post Dec 7, 2022, 10:49 a.m. EST
Henrik Sönnerlind COMSOL Employee

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Posted: 2 years ago Dec 6, 2022, 5:04 a.m. EST

There is one limitation if you are going to use 2D axisymmetry with circumferential displacement. Since the application is wire drawing, I assume that contact is an important part of the simulation. No slip velocity in the circumferential direction is available. Thus, all friction forces will act only in the RZ-plane. But if that approximation is OK, then there is no problem with the other nonlinearities.

If you want a 3D model, then you can just do a Revolve operation on the 2D geometry. You can perform the analysis on a sector, and avoid using the full cylindrical geometry. In that case, you need to use a periodic condition between the cut boundaries.

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Henrik Sönnerlind
COMSOL
There is one limitation if you are going to use 2D axisymmetry with circumferential displacement. Since the application is wire drawing, I assume that contact is an important part of the simulation. No slip velocity in the circumferential direction is available. Thus, all friction forces will act only in the RZ-plane. But if that approximation is OK, then there is no problem with the other nonlinearities. If you want a 3D model, then you can just do a Revolve operation on the 2D geometry. You can perform the analysis on a sector, and avoid using the full cylindrical geometry. In that case, you need to use a periodic condition between the cut boundaries.
Kimberling Sanchez
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Posted: 2 years ago Dec 6, 2022, 11:02 a.m. EST

Hello Henrik,

thank you very much for your answer. In the drawing process I want to do it in normal 2D-Axisimetric, so I think there would be no problems.
On the other hand, after I want to apply the torsion on the drawn wire that I got in 2D-Axisymmetric. So from your answer I assume that in this case it is possible to use the circumferential displacement in 2D-Axisymmetric and at the same time generate large strain, correct?
I have some additional questions please:

  1. I will obtain the 2D-Axisymmetric drawn wire as the result of a study, so is it possible to use this result as a model/component to carry out another study on it (the torsion I want to apply)?
  2. Is it necessary to use rigid connectors to generate the torque? Is there any link where I can get detailed information about how to use it?

I thank you in advance for your attention!

Hello Henrik, thank you very much for your answer. In the drawing process I want to do it in normal 2D-Axisimetric, so I think there would be no problems. On the other hand, after I want to apply the torsion on the drawn wire that I got in 2D-Axisymmetric. So from your answer I assume that in this case it is possible to use the circumferential displacement in 2D-Axisymmetric and at the same time generate large strain, correct? I have some additional questions please: 1. I will obtain the 2D-Axisymmetric drawn wire as the result of a study, so is it possible to use this result as a model/component to carry out another study on it (the torsion I want to apply)? 2. Is it necessary to use rigid connectors to generate the torque? Is there any link where I can get detailed information about how to use it? I thank you in advance for your attention!
Henrik Sönnerlind COMSOL Employee

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Posted: 2 years ago Dec 7, 2022, 2:52 a.m. EST
  1. The easiest is to just continue with a second study step, and automatically start from the state from the previous study step. You can have the circumferential displacements active all the time. You can choose to constrain them in the first study step (although it would not be necessary).
  2. The Rigid Connector feature is not available for 2D axisymmetry. You can simply apply a boundary load in the phi direction, having a linear variation in the R direction.
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Henrik Sönnerlind
COMSOL
1. The easiest is to just continue with a second study step, and automatically start from the state from the previous study step. You can have the circumferential displacements active all the time. You can choose to constrain them in the first study step (although it would not be necessary). 2. The *Rigid Connector* feature is not available for 2D axisymmetry. You can simply apply a boundary load in the phi direction, having a linear variation in the *R* direction.
Kimberling Sanchez
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Posted: 2 years ago Dec 7, 2022, 10:49 a.m. EST
Updated: 2 years ago Dec 7, 2022, 1:02 p.m. EST

Hi Hendrik,

thank you very much again. One more question, maybe it's very basic because I'm a beginner. In this torque analysis, I want to rotate 5 complete turns, should I apply a constant force that generates the torque for a certain time or what would you suggest?

By the way, everything discussed about torsion in a 2D-axisymmetric model is valid for a time-dependent analysis, correct?

Thank you very much in advance!

Hi Hendrik, thank you very much again. One more question, maybe it's very basic because I'm a beginner. In this torque analysis, I want to rotate 5 complete turns, should I apply a constant force that generates the torque for a certain time or what would you suggest? By the way, everything discussed about torsion in a 2D-axisymmetric model is valid for a time-dependent analysis, correct? Thank you very much in advance!

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