Background

The reasons for mesh refinement along surfaces are rather similar to those listed for mesh refinement within volumes. What is different are the circumstances and the timing of a particular refinement engagement. Some general guidelines can be outlined as follows.

Refinement within volumes

This procedure is typically applied at the early and developed stages of the topology optimization process. At these stages complete volumes have to be addressed because the design is still changing significantly.

Refinement along material-void boundary surfaces

This procedure is typically applied at the very late stage of the topology optimization process. At this stage the topologically optimal design is more or less finalized and this refinement may improve the fine tuning of the cut surfaces within the final few optimization cycles.

Refinement along stripped surfaces

This procedure is typically applied at various stages of the shape optimization process. This refinement may prove to be very helpful to:

• reduce the distortion of near-surface elements;
• improve the geometrical smoothness of the final surface;
• improve the stress distribution uniformity at the final surface;
• improve the numerical accuracy of the stresses computed at the surface.

NOTE. Regardless of the refinement type, these procedures should always be engaged cautiously and gradually with carefully chosen refinement parameters.