Refinement

There are many situations where you are more concerned with the accuracy in certain areas of a model than others. Therefore, you will want to have a fine mesh in those areas to ensure accurate results. However, if you create the surface mesh of the entire model with a fine mesh size, you may spend unneeded time analyzing the fine mesh in regions where the results are not as important to you.

The solution to this problem is to use refinement points. A refinement point specifies a region or volume of space in which a finer mesh will be generated. These can be added in the FEA Editor environment using the following methods.

Refine an entire surface

Note: Applicable to CAD solid models only.

Use the following steps to specify a finer mesh over an entire surface of your CAD model.

1. Click SelectionSelectSurfaces and select one or more surfaces on which the same refinement parameters are appropriate.
2. Click MeshRefinementAdd to Selection, or right-click in the graphics window and click AddSurface Refinement. The surface refinement dialog box displays.
3. Specify the appropriate refinement parameters.
4. Click OK to complete the definition. A new entry displays under the MeshesSurface Refinement node in the browser.
5. Generate the mesh.

Refine around a point in space

Note: Applicable to CAD solid model meshes, surface mesh enhancement, and 2D mesh generation.

Use refinement points to refine the mesh within a sphere around each refinement point. Any elements within the sphere are refined, including elements on different parts.

Use the following steps to specify a finer mesh around a point.

1. Specify the location of the refinement points using one of the following methods.
   • If a mesh exists, click SelectionSelectVertices and select one or more vertices around which the same refinement parameters are appropriate. Click MeshRefinementAdd to Selection, or right-click in the graphics windows and click AddRefinement Points.
   • If you know the coordinate of the refinement point, such as the center of a hole, right-click in the graphics windows and click AddRefinement Points.
   • If you are working in a drawing plane, for 2D mesh generation, right-click in the plane at the appropriate location and click AddRefinement Points.

   The surface refinement dialog box displays.

   Note: To use the right-click context menu, ensure that you do not have any objects selected.
2. Specify the appropriate refinement parameters.
3. Click OK to complete the definition. A black dot displays on the model.
   Tip: Click MeshRefinementVisibility to display the refinement points as black dots on your model. Click Visibility again to hide the refinement points.
4. Generate the mesh.

Modify or delete a refinement

To change the parameters for existing refinement points, select the points on your model, right-click, and click Edit. The appropriate refinement dialog box displays. For surface and edge refinements, right-click the appropriate node in the browser and click Edit. You can also edit multiple refinements simultaneously, however, when you can only change fields with the same input - fields with conflicting input are unavailable.

To makes changes in the Refinement Point Browser, click MeshRefinementSpecify Nodes. You can change parameters (double-click the appropriate cell), delete individual points (highlight rows and click Remove), or delete all points (click Clear).

To delete an existing refinement, select the refinement, right-click, and click Delete.

Refinement parameters

In the refinement dialog box, set the refinement parameters appropriate to your analysis.

• X, Y, Z specifies the coordinates of your refinement point. If you have multiple vertices selected, the coordinate fields are unavailable.
• Effective radius specifies the radius of the sphere, centered about the refinement point, within which all elements are refined regardless of their parent part.
• Mesh size specifies your target side length for elements within the refinement region. Beyond the refinement region, the mesh transitions to the normal mesh size. You can only specify a value smaller than the average mesh size.
• Divide factor specifies a number by which to divide the normal mesh size.

Regardless of the refinement method you use, the mesh size you specify is approximate. As the refinement process creates a whole number of elements, you can end up with more or less elements than you expect. This variation in number of elements is most prevalent when using the divide factor method on a narrow surface.

Use automatic refinement

This command is applicable to CAD solid models only.

The Mesh Refinement Automatic command will access the Automatic Refinement Points dialog. In this dialog, you can use the slider to specify the level of refinement you want to use. Moving the slider farther to the right will result in more refinement points. When you press the Generate button, the model will be inspected for short features. Refinement points will automatically be added in these regions. If you want more or fewer refinement points, drag the slider and click the Generate button again. Once applied to the model, these automatic refinement points behave the same as any refinement point; that is, they exist at a location in space and have fixed input. (You can change the input for individual points by using Mesh Refinement Specify Nodes.)

Once the model has the desired refinement points, click the Close button on the dialog, and then re-generate the mesh (Mesh Mesh Generate 3D Mesh).

Parent topic: Meshing CAD Solid Models