Jump to content
Sixuan Chen

Any better mesh strategy to avoid element quality error?

Recommended Posts

Here is our project:

We wanna do some topology optimization on a feul door component as you can see in attached figure:

We used two surfaces to trim the oringinal solid part into 3 separate components. We wanna keep the blue and yellow unchanged and minize the weight of the red part while still satisfy some strength requirement.

 

We used tetra element and mesh the component autoly. As you can see, there are some low quality, flat and squeezed elements (white ones in the black circle) near the intersection area between design and undesign space. After I set up everything (Boundary condition, Force, Optimization settings), and click optistruct, the system operator tell me that we failed in element quality check. I think it perhaps has sth to do with the model geometry.

 

Here is the problem:

Now that we cannot change the model geometry, is there any better mesh strategy to obtain a better mesh to pass the element quality check? (I know that auto mesh is definetly not an idea choice) I tried auto tetra mesh with a smaller element size and it didn't work.

Since I'm a beginner and have to learn everything from the very beginning, can you also provide me some basic tutorial links? (Video tutorial will make life much eaiser lol)
 

project.png

Share this post


Link to post
Share on other sites
Guest
14 hours ago, Q.Nguyen-Dai said:

 

No, I see ... nothing

 

I don't SEE either :) 

 

Maybe you can use QI optimize mesh with all your quality parameters checked.

 

You can also bypass the quality issue using ControlCards>>PARAM>>elemcheck>>NO

Share this post


Link to post
Share on other sites
11 hours ago, Prakash Pagadala said:

I don't SEE either :) 

 

Maybe you can use QI optimize mesh with all your quality parameters checked.

 

You can also bypass the quality issue using ControlCards>>PARAM>>elemcheck>>NO

Oh, what do you mean by can see nothing? You mean can't see the figure?

 

Sorry....What is QI optimize mesh? Any tutorial so that I can learn?

project.png

Share this post


Link to post
Share on other sites

Here're my remarks:

  1. Because it's the same material, you can merge two solids in order to avoir bad elements
  2. Because it's not the same material and because of tangential surface, there're ALWAYS some bad elements at this zone. You can decrease element size but that does not remove all bad elements.

solid_hinge.png

Share this post


Link to post
Share on other sites
1 hour ago, Q.Nguyen-Dai said:

Here're my remarks:

  1. Because it's the same material, you can merge two solids in order to avoir bad elements
  2. Because it's not the same material and because of tangential surface, there're ALWAYS some bad elements at this zone. You can decrease element size but that does not remove all bad elements.

solid_hinge.png

Yes, the blue comp (pin) and the red comp (hinge) are the same mat, but we only wanna do topology optimization on the hinge. I think that if we merge these two components, we'll unable to do optimization separately on the hinge, am I correct?

 

For the second tip, now that bad elements always exist, does this mean we can never carry out the topo opt since we'll always fail the element quality check? How can we solve this problem? Skip the quality check, change the model geometry, or other ways?

 

Thank you!

Share this post


Link to post
Share on other sites
Guest
On 11/23/2016 at 1:19 AM, Sixuan Chen said:

Yes, the blue comp (pin) and the red comp (hinge) are the same mat, but we only wanna do topology optimization on the hinge. I think that if we merge these two components, we'll unable to do optimization separately on the hinge, am I correct?

One way is merge the components as @Q.Nguyen-Dai suggested and move the elements which falls under blue part (approximately) in to a different component and make it as a non-design space for optimization. The other way is extract faces on the hinge (where the blue part and hinge meets) and mesh in to two components.

On 11/23/2016 at 1:19 AM, Sixuan Chen said:

For the second tip, now that bad elements always exist, does this mean we can never carry out the topo opt since we'll always fail the element quality check? How can we solve this problem? Skip the quality check, change the model geometry, or other ways?

You can Bypass the element quality check. Use the control card CHECKEL>>NO

 

Goto Analysis>> Control Cards>>PARAM>>CHECKEL>>NO

Share this post


Link to post
Share on other sites

×
×
  • Create New...