Creating midsurfaces before meshing

Video: Create a midsurface

For certain types of parts, you can simplify your geometry for CAE analysis by creating a midsurface on a solid body. The commands on the Geometry Preparation group let you generate an approximation of the part's medial surface between pairs of surfaces.You can then perform your CAE analysis directly on that midsurface, rather than on the original solid model.

Midsurfaces:

• Let you simplify a model for analysis. When you create a midsurface, you can ignore fillets, rounds, or bosses that are not important for your analysis.Meshing and solving a model comprised of a solid body or bodies is usually more time and resource intensive than meshing and solving a model comprised of sheet bodies. You can create a midsurface to perform a first-pass, general analysis of the part using a 2D mesh on the midsurface.

• Are most appropriate for thin-walled parts. For more information, see Selecting appropriate parts for midsurfacing.

• Can be created either directly on the CAD geometry or on an idealized part. If you do not have write access to the original CAD part, or do not want to directly modify that geometry, you can create the midsurface on the idealized part instead.Note: If you create a midsurface on the idealized part, you must first either promote or WAVE link a body before you can create a midsurface. For more information, see Associative copy techniques for CAE workflows

• Contain information about the geometric thickness of the paired surfaces. When you mesh the midsurface, you can use the midsurface's thickness data to define the thickness of the elements in the mesh.For uniform geometry with a constant thickness, the midsurface thickness is constant.For non-uniform geometry with a varying thickness, the midsurface thickness varies.For information on overriding or ignoring the midsurface thickness values, see Shell thickness.

• Are generally created as part of a multi-step process. After you create all the necessary mid-sheets that comprise the midsurface of your part, you may need to use additional Modeling or polygon geometry commands to ensure that the midsurface is fully stitched.

The following graphic shows a solid body with a number of ribs and fillets (A). (B) shows the midsurface that was generated on that body. (C) shows the 2D mesh that was generated on the midsurface. Notice how the thickness of the original body is applied to the elements.

Note:

In general, the midsurface commands are not intended for use by designers. Because a midsurface is a simplification of exact geometry, it is usually not sufficient for detailed design applications.

Using the Geometry Preparation group

All midsurface-related commands are located on the Home tab→Geometry Preparation group. By default, this group contains the midsurface creation commands, as well as Modeling commands, such as Trim and Extend and Sew, that you can use to modify midsurfaces.

You can also customize the commands available on the Geometry Preparation group by adding commands that you commonly use in a midsurface workflow, such as Promote and Through Curves. The Geometry Preparation group is available in the Pre/Post and Modeling applications.

Selecting a Midsurface creation command

Use one of the following commands to create a midsurface:

• Midsurface by Face Pairs : Creates a midsurface halfway between sets of opposing face pairs. The face pair method is useful for creating midsurfaces for thin-walled parts with ribs. See Creating a midsurface by pairing faces for more information.

• User Defined : Designates an existing sheet body as the midsurface of a part. That is, you can manually model a sheet body to approximate the midsurface of a thin-walled part and then use that sheet body as the midsurface for your part. See Creating user-defined midsurfaces for more information.

Where do I find it?

With the part or idealized part active, Home tab→Geometry Preparation group.

How do I

Create a midsurface by face pairs

Modify the face pairs in an existing midsurface

Define a midsurface with the Offset method

Define a midsurface with the User Defined method

Insert a replacement mid-sheet into a face pair

Learn more

Selecting appropriate parts for midsurfacing

Creating a midsurface by pairing faces

Understanding face pair creation

Working with the Face Pair list

Understanding midsurface creation and trimming methods

Controlling midsurface display

Creating a midsurface with the Offset method

Creating user-defined midsurfaces

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

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Creating midsurfaces before meshing, Simcenter 3D 2021.1 Series

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