3D Topology Optimization - Is it compulsory to redo geometry every time?

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  • Last Post 17 December 2018
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timlim123 posted this 13 December 2018

I am unable to mesh on the new model (after topology optimization) due to poor quality of the elements, I have tried meshing using very small element sizes without any success. 

 

My current standard of procedure after topology optimization is as follows :

1. Insert a plane then extract curves

2. Fill Geometry and pull surface to the initial thickness of the geometry

3. Suppress previous solids.

 

It is necessary to do this every single time in order to successfully mesh over the model?

A side question, anyone has any help documentation for ANSYS regarding topology optimization? I'm unable to find any.

 

Thank you for your attention and time. (I have attached an image showing what happens if you do not fix the geometry)

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kkanade posted this 14 December 2018

as ansys employees, we can not download images. can you please insert images or a sketch explaining issue with arrows. 

also procedure you have written is not clear to me. please explain procedure in detail with the help of images. 

timlim123 posted this 14 December 2018

The error for mesh quality (model of beam directly linked after topology optimization without any "fixing" of the geometry):

Error

 

Every time after executing topology optimization, I won't be able to generate a mesh onto the new model. I have watch a few videos on topology optimization and realized that everyone will "repair" their geometry before proceeding to meshing. I want a confirmation on whether is it compulsory to:

 

1. After topology optimization, you will be given a new model, I will suppress it because the model is useless as I cannot mesh it:

 

2. I will insert a plane and use the "Extract Curves" function to get the outlines of the new model:

 

 

3.  After getting the curves, I will "Fill" the curves and then use the "Pull" function to revert the model into a 3D model according to the thickness that I want.

 

I am thinking that there will definitely be a better way to do it in ANSYS or must we redo the geometry every time after topology optimization?. Are there any particular topology optimization documentation for ANSYS that I could get my hands on? 

 

Side question: I am also trying to set up a new constraint (not in the default, stiffness of the object) but I have no clue where to start.

 

Thank you for your attention kkanade, your help is much appreciated. Have a great weekend ahead.

kkanade posted this 14 December 2018

should i move this to structural mechanics category to get better answers?

timlim123 posted this 14 December 2018

Yes, sure thing. 

timlim123 posted this 16 December 2018

Has the post been shifted?

peteroznewman posted this 16 December 2018

timlim,

To answer your side question on documentation, when I type topology optim into the ANSYS Help system, I get a lot of hits.

On the question of rebuilding geometry after a Topology Optimization, yes, that is a necessary step. T.O. suggests a good shape. You need to work it into clean geometry. 

Regards,
Peter

timlim123 posted this 17 December 2018

Hi peteroznewman,

 

Thank you for the help.

 

Regarding the documentation, I have read through it completely and I still cannot figure out how to set up a response constraint that is not included in the default (mass,volume,stress,natural frequency). I want to set up a response constraint that involves the modal stiffness of the structure, any ideas on how could this be done or whether is it possible to do in ANSYS in the first place?

 

Sorry for the trouble, thank you for your answer!

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