# Questions about Meshing in Explicit Dynamics

Member Posts: 3

Hi,

I have some questions about importing meshed bodies into Explciit Dynamics and about meshing in general.

If a .nas file with a predefined mesh (containing either prism, tetrahedral, hexahedral, or combination of them) is imported into an Explicit Dynamics simulation, does ANSYS subdivide prism elements into tetrahedral elements?

When a mesh containing tetrahedral and prism elements is imported, the mesh is shown to contain Tet4 and Wed6 elements (I'm assuming tet refers to tetrahedral and wed is for wedge elements (ANSYS's term for prism elements) - is this correct?). Or are prism elements broken down into tet elements by the solver before the simulation starts?

Some other questions of interest are:

Can ANSYS take in tet-hex mixed elements? How about pyramid elements?

Can tet elements be directly connected to hex elements? Or is this an issue since tet elements have a triangular face, and hex elements have quadrilateral faces?

Does ANSYS allow for connections between half quadrilaterals (two neighboring hex elements only sharing half of a face)?

Can ANSYS accept connections between a pair of prism elements and a hex element by sharing a quadrilateral from a hex and two triangles from prisms?

Thank you.

• Posts: 11,404Member

Does ANSYS subdivide prism elements into tetrahedral elements?

Yes because the way ANSYS creates a Prism shape is by collapsing one face of a Hex Element and using duplicate nodes on two corners. Prism elements are turned into three tet elements in the Mechanical program before any input is sent to the solver.

Can ANSYS take in tet-hex mixed elements? How about pyramid elements?

Yes.

Can tet elements be directly connected to hex elements?

No, that is what pyramid elements are for.

Does ANSYS allow for connections between half quadrilaterals (two neighboring hex elements only sharing half of a face)?

You seem to be mixing up shell and solid elements. Do you mean quadratic hex elements that have midside nodes where the connection is on half a face? That is not recommended. Explicit Dynamics only works with Linear Elements, so I think the answer is Ansys would reject that as an acceptable mesh.

Can ANSYS accept connections between a pair of prism elements and a hex element by sharing a quadrilateral from a hex and two triangles from prisms?

Please show an image of what you mean.