Do I have to mesh the entire model in one operation?

When you mesh a selected region, Abaqus/CAE tries to preserve the existing mesh in other regions of the model if possible. However, incremental meshing may force the nodes on the boundaries of the existing mesh to move and can reduce the mesh quality along the interfaces between the regions. If your part or part instance contains a seam crack, you must mesh the part or part instance in a single operation; incremental meshing is not supported.

In some cases Abaqus/CAE cannot proceed with an incremental meshing operation and must delete all the existing meshes before proceeding:

• Incremental meshing cannot proceed if the seeding between the existing mesh and the selected region cannot be honored. You must allow Abaqus/CAE to delete the existing mesh and remesh the original regions and the selected region.

  For example, consider the part instance in Figure 1.

  Figure 1. The central region cannot be meshed incrementally.
  
  

  The central region cannot be meshed incrementally because one end has a mesh with 4 × 4 mesh pattern and the opposite end has a mesh with a 3 × 3 mesh pattern. If you try to mesh only the central region, Abaqus/CAE will detect the problem and allow you to choose between the following:

  • Remesh the regions that are already meshed and the central region to generate a compatible mesh.

  • Cancel the operation to mesh the central region.

• Incremental meshing cannot proceed if the existing mesh needs to be derived from the mesh you are trying to create. For example, consider the part instance in Figure 2.

  Figure 2. The regions must be meshed in the correct sequence.
  
  

  To create a compatible mesh between region 1 and region 2, the mesh of region 2 is derived from the mesh of the cylinder in region 1. Similarly, the mesh of region 3 is derived from the mesh of region 2, which in turn was derived from the mesh of the cylinder in region 1. As a consequence, if you mesh region 3 first, Abaqus/CAE cannot incrementally mesh regions 1 and 2. You must allow Abaqus/CAE to mesh region 1 prior to remeshing regions that were already meshed.

If incremental meshing cannot proceed, Abaqus/CAE displays a warning message prior to deleting an existing mesh.

If you want to mesh the part or assembly incrementally, you can follow a strategy that will minimize the number of times Abaqus/CAE has to delete the existing mesh. The meshing strategy depends on the topology of the regions, the element shapes, the meshing technique, and the mesh seeding.

• Changes to the seeding always propagate out to the boundaries. As a result, you should start meshing from the interior of the part or part instance and continue out to the boundaries of the part or instance.

• However, if you can identify a set of adjacent three-dimensional regions that will be meshed using the swept method, you should start meshing on one side of the part or part instance and continue the mesh through the interior to the other side of the part or instance.

• Regions that are meshed by triangles or tetrahedral elements will never force the entire mesh to be deleted during incremental meshing. The same is also true for regions that are meshed by quadrilateral-dominated elements using the advancing front algorithm. Abaqus/CAE can always remesh these regions, and you can mesh them at any time.