About Manufacturing Conditions and Geometrical Restrictions

For the topology optimization with Tosca Structure, it is possible to define constraints (DVCON_TOPO) that have a direct influence on the individual design variables (DV_TOPO). This allows the manufacturing restrictions or geometrical design aspects to be taken into consideration in the topology optimization.

See Also
In Other Guides
DV_TOPO
DVCON_TOPO

The different restrictions are listed below:

  • Frozen area
    • Element fixing by exclusion from the optimization group.
    • Element fixing by freezing elements (FROZEN).
  • Manufacturing control
    • Prevention of undercuts in the model (CAST).
      • Casting - the remaining structure can be produced by casting (MID_PLANE = POINT)
      • Forging - the remaining structure can be produced by forging (MID_PLANE = NONE)
      • Stamping - the remaining structure can be produced by stamping (MID_PLANE = STAMP)
      • Definition or automatic determination of the middle plane (MID_PLANE = AUTO)
      • Tightness of resulting structures (MID_PLANE = AUTO_TIGHT)
      • Alternative approach for demold constraints by parameterization of the design variables (FILTER_PARAM = YES)
    • Prevention of overhangs in the model (OVERHANG).
    • Enforcing a millable result (MILLING).
    • Enforcing a rib pattern (RIB_DESIGN).
  • Symmetry control
    • Area linking (LINK_TOPO)
    • Symmetry restriction (LINK_TOPO)
  • Member size control
    • Minimum member size control (MIN_MEMBER)
    • Maximum member size control (MAX_MEMBER)
Note: Manufacturing constraints might require a significant amount of additional computation. This can have a negative impact on performance, which increases with model size. To reduce the calculation time, most of the manufacturing constraint can make use of shared memory parallelization. The number of threads Tosca Structure should use must be set by the user, either with the command-line parameter --cpus x, where x is the number of threads, or the environment variable FED_OMP_NUM_THREADS. The maximum number of usable threads is given by the number of available CPUs. By default, Tosca Structure will not run in parallel and only use one thread. The manufacturing restrictions that support shared memory parallelization are MIN_MEMBER and MAX_MEMBER control, all CAST variants without the FILTER_PARAM=YES option, MILLING, and RIB_DESIGN.