Could someone help me with this question?

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  • Last Post 16 December 2018
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shilan posted this 13 December 2018

Hello Ansys Team,

I am very much new in using ANSYS  Workbench. I have an internal complex shrinkage porosity in a fatigue sample.  At first, I have tried to do the mesh study without "sphere of influence". Now, I would like to enclose my defect with a sphere and then extrude a cylinder around the enclosed defect (because of the shape of fatigue sample). I  tried differet ways but unfortunately I was not  successful. Could anyone help me with this question? I will be really grateful.

To clarify the type of defect that I have, I will upload the files. Please take a look.

Attached Files

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peteroznewman posted this 14 December 2018

Hello,

The ANSYS employees are not permitted to download attachments. I opened the IGES file you attached and find 2344 surfaces that look like this:

I don't understand what you want to do with this geometry. SpaceClaim can stitch these into a solid. Then what?

kkanade posted this 14 December 2018

thanks Peter!

 

dadashilan80,

 

this looks like a mesh file or faceted data. if you are doing any fluid analysis, it would have been very simple by using fluent meshing. but as you are using ansys, you may need to create a solid out of this using spaceclaim before proceeding. please check following videos on spaceclaim which may help you to create solid body of your geometry. 

 

 

 

 

shilan posted this 14 December 2018

Hello,

 

It is the first time I use this website. I did not know that, sorry. What I need to do is to apply firs a tensile load and stud the stress concentration around this defect. If it was your question. @peteroznewman

 

Shilan

shilan posted this 14 December 2018

Thank you so much. I will lookk at those videos @kkanade.

Shilan

shilan posted this 14 December 2018

Thank you so much for those videos. 

My main goal is to study the stress concentration around this complex shape in a fatigue sample. What I have learned if I make a "Sphere of influence" around this defect, I will be able to do the "Mesh Study" in a better way. But, I don't know how to enclose this defect in a sphere.

Regards,

 

shilan posted this 14 December 2018

It is the first time I use this website. I did not know that, sorry. What I need to do is to apply first a tensile load and study the stress concentration around this defect. My question was: I do not know how to make "Shpere iof Influence" for this type of geometry. 

 Regards,

kkanade posted this 14 December 2018

'sphere of influence' is used for mesh refinement. it this you want?

 

shilan posted this 14 December 2018

Thanks for your reply. Yes, I have watched this video. However, I want my whole defect inside a sphere. So when I applied the method of this video . it did not work for me.

 

 

kkanade posted this 14 December 2018

can you please check the sizing used? can you please reduce the size for sphere of influence? 

can you please post image from meshing?

shilan posted this 14 December 2018

Here is the Mesh Study file without any sphere of influence. I think I have clarified I DO NOT know how to make the sphere around this defect!! ... sorry for any inconvenience and confusing. I will attach 4 images and 1 table respectively. In this mesh study, there is no sphere around the defect. The only thing around the defect is the cylinder which is the fatigue sample gage length.

shilan posted this 14 December 2018

Plus I can not reduce mesh size more than this.

shilan posted this 14 December 2018

shilan posted this 14 December 2018

shilan posted this 14 December 2018

and this is the mesh of the geometry itself.

 

 

 

peteroznewman posted this 15 December 2018

shilan,

Let me describe what I think you have done, so you can correct me if I am wrong. You have:

  • a cast metal cylinder physical sample to test fatigue
  • done a CT scan of that volume of metal
  • reconstructed the surface of a void inside the metal cylinder
  • exported an iges file of the surface of the void
  • created solid geometry of the metal cylinder in SpaceClaim
  • imported the iges file of the void into SpaceClaim
  • converted the surface model of the void into a solid body
  • used the Combine tool in SpaceClaim to remove the void body from the cylinder body

Now you want to do a mesh refinement study.  You need to:

  • Create a Coordinate System, use Global Coordinates to get the Origin approx. at the center of your void
  • Add a Sizing mesh control to the body of the metal cylinder with the void
  • Change the Sizing Type to Sphere of Influence
  • Select the Coordinate System made above
  • Type an Element Size
  • Type a Sphere Radius

Which part is not working for you?

I would add that in SpaceClaim, you can merge some of the facets on the void surface that are not near the "edges" of the void and are on the larger side "face" of the void.  This will help reduce the element count in the model.

For a mesh refinement study, the mesh size in the sphere of influence should start at the size of the facets of the void because your initial mesh starts at that size. You only get meaningful results when the element size is smaller than the facet size.

Regards,
Peter

shilan posted this 16 December 2018

Hello Peter,

I truly appreciate your detailed reply.

In the first part, all the steps you have mentioned are correct except that I have imported the geometry in DesignModeler not in SpaceClaim.  

I will definitely apply your recommendations to make "Sphere of Influence" and come back to you.

Sincerely,

 

Shilan

peteroznewman posted this 16 December 2018

Hello Shilan,

If my post above answered your question, please click the Is Solution link below that post to close this discussion.

Open a New Discussion for a new question. 

Regards,
Peter

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