Work Locally
Save models on a local drive not a network location. If the CAD model is on a network drive, transfer the model to Autodesk Simulation, and then use the Save As command to save the FEA model to the local computer.
CAD models are solid models with surface information or wire frame models. The CAD solid models can be automatically meshed using the capabilities of the Autodesk Simulation user interface. Wire frame models cannot be meshed automatically (except for flat, 2D models) and are typically used for line elements or as edges of hand meshed models.
A CAD model cannot be opened from the user interface or transferred from the CAD package to the user interface if any of the following conditions are true:
If any of the above are true, the import will be aborted. In some cases, you are informed that they first need to convert their legacy model by opening it. After the old model is converted, the new CAD model can be imported.
When dealing with CAD solid models, follow these guidelines to avoid FEA modeling issues.
| Guideline | Notes |
| Use the proper element type. |
CAD solid models are generally used to generate brick elements, but parts with thin walls do not always give the best results with brick elements. Thin-walled models may give more accurate results if used to generate plate elements. This may influence how much detail is put into the CAD solid model. |
| Remove parts that are not relevant to the stress calculations. | Simplify complicated assemblies by eliminating some parts. The only reason some parts are in an assembly is to prevent other parts from moving in a particular direction. Replace them by properly constraining the model. Other parts are simply there to connect two parts together, such as screws and pins. These types of connections can be simulated more efficiently by connecting the nodes of the parts together (replacing the screw) or by using other element types, like beam and truss elements (replacing the pin). |
| Remove unnecessary details. | Many assemblies have small features such as fillets or holes that will not affect the results. To accurately represent such features, they will require a finer mesh size in those areas, which could result in significantly more elements. Remove these features to reduce the analysis time. Most complex features can be suppressed in the CAD software by selecting the Simplify Model command. You can suppress features individually or globally in the model through the use of sliders. |
| Split surfaces |
Many loads in Autodesk Simulation are applied to surfaces of a model. If a load applies to only a portion of a large face, split the surface in the CAD software. It places the region to be loaded on a unique face which will remain a unique surface. (Check the documentation for your CAD software. See split lines, imprint, split face, split part, and project geometry.) Another use of splitting a surface would be to control how the surfaces are created along a cylindrical hole. Most CAD packages create two semicircular surfaces. and rotate them 90 degrees from how you would need them to properly apply a load. |