Abaqus Release Notes  


12.6 New tools for editing orphan mesh parts

Product: Abaqus/CAE  

Benefits: You can now have Abaqus/CAE grow element edges that are smaller than a minimum criteria. You can also merge or subdivide element layers to modify an orphan mesh.

Description: When you use the Edit Mesh toolset to work with an orphan mesh, three new tools are now available:

When you use the Grow short edges tool, you specify a minimum edge size; and Abaqus/CAE lengthens any edges in the mesh that are smaller than the minimum by shortening the adjacent element edges. By default, Abaqus/CAE checks all element edges in a mesh part for short edges, but you can specify a different element domain. You can select a thickness direction and/or a reference edge to indicate that Abaqus/CAE should check for short edges in only that direction. Using a thickness direction vector also allows Abaqus/CAE to grow edges in model areas that contain adjacent short edges by progressively moving nodes in the specified direction. Without a direction vector, Abaqus/CAE treats each edge individually and cannot grow a short edge if adjusting its nodes would collapse or invert the surrounding elements. The element domain, thickness direction, and reference edge options have also been added to the existing Collapse short edges tool, and the tool can now be used with other element shapes in addition to triangular elements.

The Merge layers and Subdivide layers tools reduce or increase, respectively, the element density in an area. The newly merged or divided elements have the same element type as the originals and are members of the same element sets. You can merge a minimum of two elements and subdivide one or more elements; however, you should merge or subdivide complete element layers or an entire mesh to maintain node compatibility. Figure 12–9 shows an orphan mesh model of a gear; the main image shows the modified mesh, and the inset shows the original mesh. The Subdivide layers option was used to add more layers radially, and the Merge layers option was used to reduce the number of layers through the thickness of the gear. The modified mesh is better suited than the original to the radial loading expected for a gear.

Figure 12–9 Using merge and subdivide to improve an orphan mesh.

The element changes that you make are included in any existing element sets. For example, section assignments will be applied to new elements created by subdividing existing elements. However, existing surfaces and node sets are not extended; therefore, after editing an orphan mesh, you must verify that any node- or surface-based entities such as loads are applied correctly to the new mesh.

Abaqus/CAE Usage: 
Mesh module:
    MeshEdit: Select the Mesh category: Collapse short edges,
    Grow short edges, Merge layers, or Subdivide layers
Reference:

Abaqus/CAE User's Manual