Topology Optimization: About
Introduction
Flux 2D provides its users with novel topology optimization tools for the design of electromagnetic devices. This new toolset complements the free-shape optimization functions already available in Flux 2D, allowing electromagnetic designers to benefit even further from the state-of-the-art structural optimization methods offered by the Flux-OptiStruct coupling.
In Free-shape optimization, the boundaries of selected parts of an initial design are iteratively displaced and modified by the procedure. The result is an improved shape that satisfies the optimization criteria and that usually resembles the original design. Topological optimization methods, on the other hand, are based upon the addition or removal of the matter composing the parts being optimized. This process is governed by the evolution of the values of a material density function throughout the optimization procedure, and frequently leads to quite innovative shapes that may not have been previously considered. Figure 1 illustrates both approaches in the simple case of the optimization of a beam.

Topology optimization strategies implemented in Flux 2D
- the Density method and
- the LevelSet method.
Software requirements
- Altair Flux;
- Altair OptiStruct.
- In Flux Supervisor, click the Options button.
- Then, in Access paths, select Coupled Software.
- Check if the field OptiStruct scripts directory is correctly
configured:
- In Windows systems, this field should contain the folder storing the file optistruct.bat.
- Similarly, in Linux systems, this field should contain the sub-folder of the OptiStruct installation directory containing the file optistruct.sh.
- The Optistruct scripts directory can also be defined through the environment variable INSTALL_OPTISTRUCT.
Current limitations
- Unavailable in the following applications:
- Steady State AC Magnetic;
- Non-magnetic or coupled applications.
- The faces being optimized need to be finely meshed. Moreover, the following
mesh types are forbidden:
- Mesh with first order elements;
- Heterogeneous meshes (i.e., mixing triangles and quadrangles).
- Axisymmetric domains are not supported yet.
- It is not possible to perform the topology optimization in Transient magnetic applications with the Initialized by file option.
- Only faces lying on Magnetic non conducting regions and Laminated magnetic non conducting regions may be used for topology optimization. Assigning other types of region (such as Air or vacuum regions, Regions with current density, Coil conductor regions and Solid conductor regions) to faces make them incompatible with topology optimization in this version.
- Only faces on regions characterized by materials with simple B(H) magnetic properties may be used (e.g., Linear isotropic, Isotropic analytic saturation, Isotropic analytic saturation + knee adjustment, isotropic spline). Faces in regions with hysteretic, anisotropic and magnet materials are not allowed.