Learning Forum

[Mattvieir]

Hey guys, i need to understand better how to deal with midsurfaces and I hope you can help me. When you convert a solid model to a shell model, most times you’ll get some gaps between the surfaces, but the way people deal with those gaps varies and I want to understand when to use each method.

In this example the author trimmed the excess from the back plate, and altered the bottom plate (the one with the holes) so it meets perfectly with the bottom flange of the beam. I’ve seen several examples like this on, where you trim and extend midsurfaces to neatly fit each other.

[1shan]

Hello Array,
A good mesh and mesh connectivity is essential to obtain an accurate result. When 2 parts mate it is not always possible to get a good mesh on both parts and ensure connectivity at the same time and that is the reason why contacts are used. In 2D modelling the first approach is to extract mid surface, do the geometry cleanup (close gaps, trim intersecting surfaces, delete duplicate surfaces which is necessary for a good connected/conformal mesh) and then create a good mesh. Now, when you do this you may or may not get a mesh which is well connected across edges/faces. In cases where you don't, some additional settings are needed to enforce the mesh connectivity. This is when the local mesh controls like "mesh connectivity, node merge, contact match" are used. Now in many cases even doing this may not work, (elements might become distorted or you may end up with a low quality mesh)then you need to go for contacts.
Also, the thickness of a 2D element is just a geometric representation. The values are computed at the mid surface nodes and are intra/extrapolated over the thickness. This may give you a slight error but it comes with a additional benefit of reduced computational expense.
Regards,
Ishan.

[mukildev]

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Hello Mattvieir,

Did you manage to find out the answer for the question you asked?

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