Correction of defects in topology optimization results

In some cases, the topology optimization results contain small irregularities that are generally not desired. In order to deal with them, the filtering of the material distribution as well as the possibility to remove small unconnected components are implemented

Filtering and repair parameters of Tosca Structure.smooth

Parameter

Value

Description

Supported by

TAe

GUI

TExt

TS.pre

TS.smooth

RESULT_FILTERING

off: no filtering

moderate: one filtering cycle

full: 5 filtering cycles

default: off

Defines the number of filtering cycles that are applied in order to make the material distribution homogeneous

a

x

x

-

COMPONENT_LIMITING_SIZE

Real value between 0 and 0.5

Default: 0

Defines the minimal allowed relative size of a connected component (calculated using its number of faces). All components with the relative size below this value are removed. Default: 0

a

x

x

x

The result filtering averages the material values ("densities") in the places where it affects the isosurface most, and therefore it may account for large changes of the surface geometry.

See the following figures for the influence of the result filtering on the geometry in various cases.

No result filtering (left)

moderate result filtering (one cycle) (right)

  


Small isolated components are removed


Narrow "bridges" are removed


Narrow caverns and small holes (including the holes inside the model) are removed

When the parameter COMPONENT_LIMITING_SIZE is set to a positive number, all connected components with the number of faces below the product <number of all faces> * COMPONENT_LIMITING_SIZE are removed. By definition, in a connected component, each two faces can be connected by a chain of other faces, so that two consequent faces in the chain have a common side.

Important:

Note that only the connectivity of the surface is checked; a hole inside the model that is completely surrounded by material is considered as a separate connected component. The removal of small connected components takes place directly after the isocut.

If more than one connected component remains, the user gets a message:

where N is the number of remaining connected components (each inner hole counts as a component as well).