If your existing mesh is a native mesh, you should create an orphan mesh. For more information, see “Creating an orphan mesh part,” Section 17.18. You can use the following procedure to embed a layer of cohesive elements:
In the Mesh module, use the solid offset mesh tool in the Edit Mesh toolset to embed elements in an existing mesh (see “Editing the entire mesh,” Section 41.7). This approach generates a layer of hexahedral or wedge elements that share nodes with the surrounding bulk material. The offset mesh tool generates elements that are oriented consistently with a stack direction that is aligned with the offset direction. When prompted to select the element faces from which the offset mesh will be generated, select the interior element faces using the procedure described in “Selecting interior surfaces,” Section 6.2.8.
Note: When generating an embedded layer of elements, the thickness should be much less than that of the adjacent elements because the nodes are displaced when the offset layer is generated.
You can create an offset mesh from only three-dimensional element faces. As a result, you can create only hexahedral- and wedge-shaped cohesive elements using an offset mesh. For example, you cannot create quadrilateral cohesive elements by offsetting from element edges.
In the Mesh module, use the element type assignment tool to assign the cohesive element type to the cohesive region. See “Element type assignment,” Section 17.5.3, for more information.
If you want to use a finer mesh in the cohesive layer, you should construct the cohesive layer as a separate part. You should separate the mesh in the surrounding bulk material into two regions with the appropriate spacing to accommodate the cohesive layer. You can mesh the cohesive layer using the methods described in “Creating a model with cohesive elements using geometry and mesh tools,” Section 21.1.3, and tie the cohesive layer to the surrounding bulk material. For more information, see “Defining tie constraints between the cohesive layer and the surrounding bulk material,” Section 21.1.4.