Source model preparation
Domain partitioning

In structural topology optimization various

have to be assigned to individual volume or surface regions of the structure under consideration. In order to be able to impose such requirements, the whole structural domain of the source model has to be partitioned into regions.

Example

The figure below shows an example of a model, partitioned into three volume regions:

Figure. A model with three different volume regions: free, fixed, and excluded.

Volume regions

ProTOp can extract geometrical volume regions data exclusively from finite elements and their material pointers. More precisely, finite elements belonging to a distinguished material define what is called a material region. Each material region is regarded as an imported volume region that can be used in further processing.

NOTE. Each source model volume region must have a distinguished material assigned to, even if the properties of all materials are the same.

In preparing the source model, the process of creating volume regions and assigning materials depends on the chosen modeler. For Creo®, Simulia® Abaqus, SolidWorks® Simulation and SIEMENS NX™ some tips are assembled in the tables below.

Table. Tips on creating volume regions and assigning materials.
PTC Creo® Simulia® Abaqus
  • Create simulation Volume Regions in the Simulation application
  • Define a list of used Materials
  • Create a Material Assignment to Volumes or Models
  • Create Cell partitions in the Part module
  • Create and define Materials and corresponding Sections in the Property module
  • Assign Sections to Partitions
SolidWorks® SIEMENS NX™
  • In the Model module use Split from the Direct Editing ribbon to create multiple bodies from a single body
  • Optionally edit or add custom materials/libraries; use Apply/Edit Material in the Simulation module
  • Apply Materials to Solid Bodies
  • Divide a body into multiple bodies by using Split Body in the Feature ribbon of the Part Modeling module
  • Optionally use Manage Materials; use Copy or Create New Material in the Properties ribbon of the FEM module
  • Assign materials to Bodies

Note that ProTOp can import and optimize a single part FEA model only. Therefore, separated volume regions must be connected into a single part.

Table. Tips on connecting separated volume regions or assembly parts.
PTC Creo® Simulia® Abaqus
  • In the Simulation application set Bonded and Merge Coincident Nodes in the Model Setup dialog box as Default Interface settings
  • Use single part to create the FEA model
SolidWorks® SIEMENS NX™
  • In the Simulation module define Contact; Contact type: Bonded; Components: Global contact; Options: Compatible mesh
  • Use Mesh Mating to connect separated solid bodies and their associated FE meshes with Mesh Mating Type, Glue-Coincident (Automatic Creation is recommended) in the FEM module

Features and limitations

Surface regions

ProTOp can extract geometrical surface regions data exclusively from finite elements and their loading data. More precisely, finite element faces belonging to a distinguished fictive surface load define what is called an imported surface region and can be used in further processing.

NOTE. Each source model surface region must have a distinguished fictive surface load assigned to, even if the properties of all loads are the same.

To create fictive surface loads ...

Features and limitations

Example

The figure below illustrates a situation in PTC® Creo® where the 'geometry-export' load case was defined in addition to two actual load cases.

Figure. Two actual load cases and one 'geometry-export' load case, defined in PTC® Creo®

After import of this FEA model into ProTOp, the situation would be like shown below, i.e., the 'geometry-export' load case is not considered as an actual load case.

Figure. List of actual load cases - without the 'geometry-export' load case.