Creating efficient CAD models for FEM simulations is not about crafting the most intricate and visually appealing designs. FEM is a computationally intensive method that necessitates meaningful and functional geometries. In this context, the principle “less is more” applies, emphasizing the importance of focusing on essential details and optimizing geometries for accurate and efficient simulations.
Main principles
To create a straightforward and problem-free geometry for your simulation, consider the following key aspects for an optimal, simulation-friendly CAD file:
- Create a single solid geometry for every separate conductor: In many CAD software programs, building the coil geometry from combined blocks is common to form a complete model. When creating geometry for simulation, these blocks should be fused to form a single solid. This helps remove unnecessary faces between blocks and simplifies geometric property setup and meshing. Coil turns that are not geometrically connected do not need to be fused but can be grouped into one partition to allow easier manipulation with the entire group.
- Simplify geometry: Computer simulations represent real physical problems through a numerical model that never ultimately represents the real world. In most cases, you can disregard specific geometrical details that have minimal impact on the result.
The most common issues and solutions
The following features can be removed or have to be fixed, as they consume a significant amount of computation time and resources without contributing considerably to the results.
Delete unnecessary elements and eliminate small details
In many cases, elements such as holding parts, dielectric tapes, and connections can be removed from the model. Small details have a negligible impact on simulation results. Still, they consume a lot of computation time, which needs to be resolved through meshing, significantly increasing the mesh element count.
Remove details such as small holes (fill in with the material) and gaps (use virtual gap model for core). Parts irrelevant to electromagnetics or heat removal from the core and windings can also be removed since heat transfer can be approximated using convective heat transfer boundary conditions.
Complex geometry turns into clean geometry. © Subhash Lathad
Resolve inaccurately connected geometrical parts
Be cautious when connecting different parts during geometry creation. Faulty connections can result in meshing problems and calculation errors. Ensure that there are no overlaps or gaps between parts.
Overlaps and gaps in imported CAD geometries. © Steven Minichiello
Ensure continuity in the magnetic component geometry
If your magnetic component features a specific channel or path, ensure it is continuous throughout the entire length to avoid meshing problems.
Terminals are not connected. © clement arnaudo
By following these tips for creating optimal CAD models, you will achieve a geometry that is easy to manipulate, mesh, and compute efficiently.
