Simulation Smart Models Instead of Dead Geometries

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Rigid CAE workflows slow down simulation: When every geometry change triggers manual update loops, it becomes time-consuming, error-prone, and frustrating. Ansys Workbench offers a different solution for this.

Do you know this? After the first simulation, changes are needed. When updating the geometry, painstakingly set boundary conditions, material assignments, or contacts are lost. It's particularly frustrating if complex defeaturing was previously done to prepare the model for the simulation. Every subsequent change then means manual work and potential sources of error.

Parametrization provides a solution here. It allows geometric changes to be implemented efficiently and consistently. Instead of manually updating each adjustment in the CAD software and then updating the simulation model, the model adjusts itself automatically. These intelligent geometries enable optimizations, sensitivity analyses, and automated workflows. This increases the traceability of decisions and accelerates product development. In short: those who use parametrization lay the foundation for efficient simulation processes.

Bidirectional Working With Other CAD tools

Many CAD systems offer extensive capabilities for working parametrically. Through the bidirectional CAD interface, such models can be directly integrated into the simulation tool Ansys Workbench. When a parameter change is made via the Parameter Set in Ansys, the associated CAD tool is used to update the geometry. To do this, the corresponding geometry is first loaded into a geometry cell in Ansys Workbench. For Workbench to recognize the parameters, they must be uniquely named in the CAD tool. This can be accomplished with a prefix in the parameter name, such as "ANS_". The prefix can be checked and adjusted in the "Properties". The parameters appear in Ansys Mechanical in the structure tree under Details for each body. A click on the checkbox shows a "P". This allows lengths, angles, or other dimensions to be specifically controlled and varied in studies using the Parameter Set.

History-Based Modeling Vs. Direct Modeling

History-based modeling is the standard for many CAD systems. The model is created step by step, with all features documented in the model tree. Ansys Discovery, the standard modeler from Ansys, uses a different approach: so-called Direct Modeling. This method eliminates a feature history, listing parts, surfaces, and curves in the structure tree instead. Users directly edit the existing geometry—ideal for quick defeaturing and flexible adjustments. For example, small features such as fillets, chamfers, or logos can be easily removed from the geometry. This makes preparation for simulation particularly efficient.

History Tracking in Ansys Discovery

If no CAD interface is available or the CAD model is not designed with a focus on parametric variation, history-based modeling can still be performed in Ansys Discovery using the History Tracking mode. This builds a feature history, similar to traditional CAD systems. However, caution is advised: switching back to Direct Modeling is not possible—the history will be lost. Therefore, it is worth having a strategy for the model setup before starting the tracking.

A practical feature is that after loading a geometry, it forms the first "block"—starting from scratch is not necessary, as demonstrated here with the example of motor cooling. Its base geometry is complex (windings, bearings, etc.), but the focus is on the heat sink. Therefore, with active History Tracking, the base (.step) is first imported. The prepared area of the cooling channels is then specifically modeled. Each editing step is saved as a block and remains editable. Initially, surfaces are created in the empty pocket, which are then patterned to form the channels. In the blocks, values such as spacing and thickness of the fins can be parameterized. There is even an option to establish dependencies between created parameters. For instance, the spacing in the pattern can be derived from the available length, the width, and the number of channels.

Sketches created during History Tracking can also be parameterized. By using the sketch symbol, you can switch to the sketch and edit it afterward. To make dimensions available outside of the sketch in the block, dimensions are set within the sketch. These appear in the block after the sketch is edited and can be used as parameters there. Dimensions that are not dimensioned remain hidden in the blocks. Additionally, constraints can also be applied within sketches to enforce restrictions such as parallelism, coincidence, or tangency.

What Should Be Considered With Geometry Parameters?

The choice of the right method depends on the goal: for complex geometries, a history-based approach with a clear build strategy is recommended. For simple variations, Direct Modeling is often sufficient. Initially, it can be beneficial not to fully parameterize every detail within the components but to start with a limited selection of parameters. This helps to better understand the fundamental functions and approaches while identifying potential pitfalls.

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