HEXA MESH

LucaC
LucaC Altair Community Member
edited October 2020 in Community Q&A

Hi everyone,
i'm a novice Hypermesh user and i'm trying to make a hexa mesh.
In the 3D panel, when i run the mesh it gives me that error 'non mappable along-faces' .
How i can solve? Is it a CAD model problem?

Thank you everyone

<?xml version="1.0" encoding="UTF-8"?>ERROR.thumb.PNG.46725616737c050ac660d639689f1844.PNG

<?xml version="1.0" encoding="UTF-8"?>ERROR.PNG

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Answers

  • Simon Križnik
    Simon Križnik Altair Community Member
    edited April 2020

    Hi,

     

    the geometry has to be properly partitioned before using automatic  hexa mesher (one volume, multisolids). In case of complex shapes, it is challenging to properly partition the solid in order to be mappable in one or more directions- it is even more challenging to strategically plan how these mappable solids come together to produce a structured mesh. Unfortnately, there is no easy fix for hexa meshing as it is the most difficult type of meshing.

     

    Refer to the following for details:



     

    https://www.altairuniversity.com/wp-content/uploads/2012/04/HM_SolidMesh_Extract.pdf

    https://altairuniversity.com/wp-content/uploads/2012/03/Bracket_Geometry.pdf

    https://blog.altair.com/art-of-map-meshing/

  • Q.Nguyen-Dai
    Q.Nguyen-Dai Altair Community Member
    edited April 2020

    When you see the message 'non mappable ...' it means that I can not do mapping hexa mesh. Sometimes I can do split more to get, but sometimes it's not possible. It's not geometrical error. Just the software can not do mapping mesh to get hexa mesh and it's mathematical.

  • LucaC
    LucaC Altair Community Member
    edited April 2020

    Thank you all for your tips. 
    I just tried to mesh my component with tetramesh and i have no problems, but when i try hexa meshing it gives me that error. 
    I look at your videos, then i mesh with hexa and run the simulation. I get a good simulation with the tetra mesh, but when i run the hexa mesh, my component gets divided, falls into pieces and this is the result of my simulation. Why I get that?

     

    Thank you everyone

     2.PNG.6ffe3f673eefedc082fa088a791b241e.PNG1.PNG.52498de8105f1168cd78aff85c8b267d.PNG

  • Ingeniorator
    Ingeniorator New Altair Community Member
    edited April 2020

    Are the nodes at the domain borders connected? Check by running equivalence.

  • Q.Nguyen-Dai
    Q.Nguyen-Dai Altair Community Member
    edited April 2020

    @LucaC share your model .hm ?

  • LucaC
    LucaC Altair Community Member
    edited April 2020

    Here is it. Could you give me some advices on my model?

     

    Unable to find an attachment - read this blog

  • Q.Nguyen-Dai
    Q.Nguyen-Dai Altair Community Member
    edited April 2020

    You have to equivalent a lot of nodes:

    nodes_equivalence.png.60f62761dbfd8844a09f756e0c110f1a.png

  • LucaC
    LucaC Altair Community Member
    edited April 2020

    How i can do that?

  • LucaC
    LucaC Altair Community Member
    edited April 2020

    I just find the equivalence option and the simulation rightly run. 
    Thank you. 

    I also have to simulate a component with 6x6x4 cells like that one i linked above. Could i duplicate mesh and then merge nodes?

  • Ingeniorator
    Ingeniorator New Altair Community Member
    edited April 2020

    Yes of course you could.

  • LucaC
    LucaC Altair Community Member
    edited April 2020
    Altair Forum User said:

    You have to equivalent a lot of nodes:

    <?xml version="1.0" encoding="UTF-8"?>nodes_equivalence.png.60f62761dbfd8844a09f756e0c110f1a.png

     



    Thank you all.
    Could you say how to see this nodes not connected?

  • Q.Nguyen-Dai
    Q.Nguyen-Dai Altair Community Member
    edited April 2020

    Tool => edges => Select elements => 'preview equiv'

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