Tech Briefs

Effective Meshes using the Size Function Option

In many problems, it is very important to be able to mesh densely in certain areas and more coarsely in other areas — like in the analysis of the helmet above, where the contact area requires a fine mesh.

ADINA 8.4 has powerful capabilities to achieve mesh gradation, in particular when ADINA-M is used. Here we feature the new Size Function option that gives great flexibility in defining mesh densities. The option is particularly useful when the densities have to be applied in specific areas of the model.

There are a number of size function types available:

  • near a point in space,
  • near an axis (straight line),
  • near a plane,
  • in and near a hexahedron of any shape,
  • in and near a bounding box, and
  • any combination of the above.

The hexahedron size function type is particularly effective for three-dimensional contact problems where the contact area is expected to be inside a hexahedron. The analysis of the helmet above involves contact modeling and makes use of the hexahedron size function.

The setup of the model is shown in the next figure. The anvil (green) is assumed to hit the helmet within the volume defined by the yellow hexahedron (size function), and this is where a finer mesh is desired. The tetrahedral mesh obtained is the mesh shown at the top of this web page.

The next figure is a closeup to show the (automatic) smooth mesh size gradation from very fine to coarse.