Defining Solid or Shell Models

You can define your model as a solid, as a shell, or as a mixed model. The model type determines the type of elements Creo Simulate uses to define your part.

• A shell model is a part that you model using shell elements like triangles and quadrilaterals. Typically, you use shell modeling when your part is relatively thin compared to its length and width. To meet the criteria for shell models, your part must have either a constant or a variable thickness in native or FEM modes.

You can change the elements used for modeling using Refine Model and then click the arrow next to

AutoGEM, and click Settings in native mode or click Home and then click the arrow next to

Mesh, and click Settings in FEM mode. For example, you can direct Creo Simulate to use only triangles to model your native mode shell model rather than using both triangles and quadrilaterals.

• A mixed model is a combination of both a solid and a shell model, where some areas of the model are better suited to shell elements and others are better served by solid elements.

In native mode, Creo Simulate treats all models as solid models by default. To direct Creo Simulate to treat your model as a midsurface shell model, or as a mixed model, you first need to define the model or some areas of it, using midsurface shell and then mesh and analyze the model:

• To mesh and analyze your model as a shell model, click Refine Model and then click the arrow next to

AutoGEM. Click Midsurface. The Midsurface option is selected by default when you create shell pairs, but if you start a new session with a model for which you created shells, you should check the setting. For example, if you have defined shell pairs for the surfaces in your model, but want to analyze the model as a solid without deleting the shells, click Refine Model and then click the arrow next to

AutoGEM. Click Solid.

• To mesh and analyze your model as a mixture of midsurface shells and solids, click Refine Model and then click the arrow next to

AutoGEM. Click Solid / Midsurface.

• When you create shell pairs, by default Creo Simulate creates Bonding Elements to link parts in an assembly. When you do not want to create bonding elements during AutoGEM meshing, clear the check box Create bonding elements on the Settings tab of the AutoGEM Settings dialog box.