Why HyperMesh selects nodes within the same component to equivalence ?

ECor
ECor Altair Community Member
edited December 2022 in Community Q&A

Hello !

I am attaching some stiffeners to a tank (Img a). I'll leave images attached to better explain the problem.

I made sure that the stiffeners' mesh is coincident with the tank's mesh. Then, I copied the surface and element so I have the four stiffeners I need.
When I select the elements and I click on 'preview equiv', HM selects also all the nodes on some of the stiffeners (Img b). If I carry out the equivalence anyway the free edges on these elements disappear (Img c). 

Do you know why is HM doing this ? 

I have tried varying the tolerance but it did not change anything. I do not also understand why it only happens in the external stiffeners and not in all of them.

 

Thanks in advance !

Cordially,

                EC

img.png 846.3K
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Best Answer

  • PaulAltair
    PaulAltair
    Altair Employee
    edited December 2022 Answer ✓

    I think the clue here is where you state 'I copied the surface and element', what I think you have done is accidentally make more than one duplicate of your stiffeners, but have left some of them exactly coincident with the originals... hence at any tolerance, however low, they would be equivalenced, and there are no free edges after equivalencing as you now have duplicate equivlanced elements in those locations (so no free edges)

    If you check for duplicate elements now (after equivalencing) those stiffeners with no free edges should light up, then you can delete the duplicate elements

    Paul

Answers

  • Adriano A. Koga
    Adriano A. Koga
    Altair Employee
    edited November 2022

    what is the tolerance value that you're using in your case? Isn't it too high?

  • PaulAltair
    PaulAltair
    Altair Employee
    edited December 2022 Answer ✓

    I think the clue here is where you state 'I copied the surface and element', what I think you have done is accidentally make more than one duplicate of your stiffeners, but have left some of them exactly coincident with the originals... hence at any tolerance, however low, they would be equivalenced, and there are no free edges after equivalencing as you now have duplicate equivlanced elements in those locations (so no free edges)

    If you check for duplicate elements now (after equivalencing) those stiffeners with no free edges should light up, then you can delete the duplicate elements

    Paul

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