How to re-mesh for a proper mesh flow?

Arun_21283
Arun_21283 Altair Community Member
edited June 2021 in Community Q&A

Hello Guys,

Background: I am trying to mesh the hood design of a car for my crash and safety simulation project. 

image\\

I have ensured proper mesh flow throughout the hood, except the left corner part of the hood. I am trying to get rid of trias and rotational quads as necessary, but unfortunately I am not successful in getting proper mesh flow.  

image

I am trying to solve for the mesh with the following parameters. 

S.N Quality Criteria  Value 
1 Aspect Ratio  5
2 Skewness 45
3 Warping 15
4 Taper      0.5
5 Min. Length 2 Units
6 Max. Length 8 Units
7 Min angle Quad 45
8 Max angle Quad 135
9 Min angle Tria 20
10 Max angle Tria 120
10 Tria %  10

Software using: Hyperworks Student Edition 2021

What I have tried so far:

1. Rebuilding Mesh: Trias or irregular quads are showing up regardless. 

2. Edit element option for moving trias forward and backward. 

Is it okay to proceed with my mock crash simulation test with the mesh flow I have right now or should I redo it?

The reason why i wanted to understand is that theoretically i learnt that the mesh flow has to be good and not irregular when carrying out crash tests. Hence I was able to achieve it elsewhere in the hood except the corner. 

Please understand that the current mesh flow has tested zero errors in the warn and fail slider in my quality check.

Your comments and suggestions are very much appreciated. 

 

 

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Answers

  • Q.Nguyen-Dai
    Q.Nguyen-Dai Altair Community Member
    edited June 2021
    1. The very important criterion is "Jacobian" does not found in your table
    2. The mesh, as shown in your picture, is not bad, even good. Why need look for elsewhere?
    3. The most important criterion of an FE meshing is giving the good and realistic results. So the "beauty" of mesh is not so important.
  • Unknown
    Unknown
    edited June 2021

    You can use the "Flow Guides" feature in the "Rebuild" tool.

     

    image

  • Arun_21283
    Arun_21283 Altair Community Member
    edited June 2021
    Hakan_21046 said:

    You can use the "Flow Guides" feature in the "Rebuild" tool.

     

    image

    Is this option available in the student version of Hyperworks ? 

    I would appreciate if you could share me how to find flow guides. I clearly don't see the flow guides or the menu/ option bar like you have in my version. 

  • Unknown
    Unknown
    edited June 2021
    Arun_21283 said:

    Is this option available in the student version of Hyperworks ? 

    I would appreciate if you could share me how to find flow guides. I clearly don't see the flow guides or the menu/ option bar like you have in my version. 

    This feature is included in the Altair HyperWorks 2021 student version. But I suggest you consider Q.Nguyen-Dai's suggestions. 

  • Arun_21283
    Arun_21283 Altair Community Member
    edited June 2021
    Q.Nguyen-Dai said:

    1. The very important criterion is "Jacobian" does not found in your table
    2. The mesh, as shown in your picture, is not bad, even good. Why need look for elsewhere?
    3. The most important criterion of an FE meshing is giving the good and realistic results. So the "beauty" of mesh is not so important.

    May I know why is it an important criterion? "jacobian" . By the looks of it (picture), all the elements looked good with a jacobian default value of 0.7. Should I be worried about it? Why can't I use a jacobian value of 1 instead 0.7? 

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