5 tools for saving time when cleaning and meshing geometry

5 Tools to Reduce Time Between Your CAD Model and FE Model

      tools to reduce time between your CAD and FE model

Creating a finite element model is one of the most time consuming processes in finite element analysis.

Using CAD geometry as the basis of your model is a huge time saver, but cleaning the geometry can take forever.

Thankfully there are tools that make geometry cleanup and mesh refinement quick and easy.

In today’s post, we’re going to show you 5 tools to edit your model, leading to well shaped mesh elements and reduced the analysis time.

1. Feature Removal

REMOVING UNNECESSARY DETAILS FROM THE GEOMETRY
In general, CAD geometry contains more detail than simulation requires.

Details such as fillets, chamfers, and small holes may be insignificant to the FE model and lead to small elements that make the finite element model (FEM) larger than it has to be.

The Feature Removal Tool allows you to remove features from the model when meshing.

You can either automatically suppress features that are less than a tolerance you specifiy.

      feature removal

or manually select the edges, loops, and faces you want to remove.

feature removal CAD

This short demonstration shows the Feature Removal Tools being used to remove small holes and fillets:



2. Geometry Editing Tools

MODIFYING GEOMETRY TO CREATE WELL-SHAPED MESH ELEMENTS
The geometry editing tool is a collection of features that allow you to edit and split the geometry into regions that will create well-shaped mesh elements.

      mesh

Pad

Select a loop (usually a curve on an internal hole or slot) and set a Factor or Distance to create a “Pad” meshing pattern.

      mesh with pad

Washer

Select a circular curve and specify a Factor or Distance for Offset Type.

      mesh with washer

Point to Point

Select two points on a surface to create a line between the points that will split the surface.

      mesh, point to point

Point to Edge

Select one point on a surface and then an edge/curve on the surface to create the shortest possible straight line from the point to the edge that will split the surface.

      mesh, point to edge

Edge to Edge

Select one edge/curve on a surface, then another edge on the surface. Alternately, choose any number of edges after selecting the first edge. Lines will be created from the end points of the “second set” of edges to the first edge.
      
      edge to edge

3. Combined/Composite Curves

COMBINING CURVES TO CREATE A HIGHER QUALITY MESH
In some cases, combining several smaller curves along the edge of a surface will allow you to create a higher quality mesh on the surface.

The Combined/Composite Curves Tool allows you to combine curves by choosing the curves themselves or a point that two curves share.

The new “Composite Curve” will be used for mesh sizing purposes instead of the underlying curves.
      composite curves

4. Combined/Boundary Surfaces

COMBINING SURFACES TO CREATE A HIGHER QUALITY MESH
Similar to “composite curves”, combining several surfaces in a “Boundary Surface” can improve mesh quality.

The Combined/Boundary Conditions Tool combine selected surfaces into one boundary surface that ignores all of the internal curves during the meshing process. (This is especially useful when there are sliver surfaces next to a much larger surface.)
      
boundary surfaces

5. Mesh Sizing

INTERACTIVELY ADJUST THE SIZE OF YOUR MESH
If you are not happy with the shape of your mesh and would like to create uniform elements, you can use the Mesh Sizing Tool to adjust the size of your mesh.

When you hover over a curve, the Entity Info Pane will display the number of elements on a curve.

You can use that information update the amount of elements on the curve and resize your mesh.

Here is a quick demonstration that shows you the capabilities of the mesh sizing tool:



Conclusion

If you use geometry as the basis of your FEA model, you will still have to bring in and clean your geometry.

Hopefully the tools we showed you today will help shave valuable time off that process.

These were just a few of the geometry editing and mesh refinement tools available in Femap.

If you’d like to see more on geometry editing, you can view our article on Manipulating Geometry and Meshing or view our free webinar on YouTube: FEA Modeling from Start to Finish.

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