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NX Simulation 7.5 3D Mesh bad quality

[ Edited ]

Hi,

 

I'm creating a 3D mesh (CTETRA10) using shell elements. However after creating 3D elements some of them have failed on Element shape check (Jacobian ratio , zero).
How to improve 3D mesh in order to achieve good quality mesh, or how to create 3d mesh from 2D elements using threshold values ?

 

EDIT:

I've forgot to add that 2D elements quality is ok.

 

 

thanks for help

8 REPLIES

Re: NX Simulation 7.5 3D Mesh bad quality

Hey Tom

 

well, first of all which elements are not good enough? first layer? internal layers? Is it 'warning elements'? Are you using different sizes in 2D and 3D meshes?

 

then you should play with parametres like transition element size, or base element size. You can also try another options like Mesh Settings.

 

Regards

Pavel 

Re: NX Simulation 7.5 3D Mesh bad quality

Hi Pavel,

Thanks for feedback.

In 3D mesh the failed elemetns are in first layer. To generate 3D mesh from 2D mesh I'm using Element Growth Rate from 0 to 100 (i've checked various numbers) but failed elements always occur.

Unfortunatly Element Growth Rate is only one option avaible in creating Solid mesh from shell form. 

Where I can find paramater  like transition element size, or base element size. or mesh settings ?

 

regards

Tom

Re: NX Simulation 7.5 3D Mesh bad quality

[ Edited ]

Hey Tom, i am confused now. Do you have the geometryat all? I thought you were using 3D tetra mesh based on seed 2D mesh...

 

Regards

Pavel

Re: NX Simulation 7.5 3D Mesh bad quality

Hi,

 

I have geometry of model.

  • At first I've created 2d mesh  using 2D mapped mesh / 2D mesh and mesh controls to mesh  all geometry.
  • Second I've checked the 2D elements quality / outlines and normals 
  • Third using 2D mesh i've created 3D mesh using Solid from shell mesh. But in this case there is no option to control 3D mesh (only Element growth rate)

regards

Tom

Re: NX Simulation 7.5 3D Mesh bad quality

well in this case let me advise you a better way to mesh your geometry. Just tick off 'Export mesh to Solver' when doing 2D mesh. And then use general 3D tetra meshing command. You will have a lot of different options and your seed 2D mesh will be taken into account

 

Regards

Pavel

Re: NX Simulation 7.5 3D Mesh bad quality

If I've undertood well.

 

I'm creating 2D mesh using 2D mesh / 2D mepped mesh with option Export mesh to solver.

And to generate 3D mesh I need to use 3D tetrathedral mesh with all options.

But please tell me the outline layer will be the same as my 2d mesh ? 

Solution
Solution
Accepted by topic author tom_gwin
‎08-26-2015 04:32 AM

Re: NX Simulation 7.5 3D Mesh bad quality

if you want 2D mesh just to guide your 3D mesh then switch OFF Export mesh to solver in 2D mesh command

And YES when you generate 3D tet mesh afterwards your 2D mesh will be the basement for the out layer. They will match. That's what we call seed mesh, so your 2D is a seed mesh for 3D mesh

 

Regards

Pavel

Re: NX Simulation 7.5 3D Mesh bad quality

Hi,
I did what you suggested and the results are much better.
Now I can control 3D mesh creation.
Thanks for support.

 

Regards
Tom