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November 2014

Geometry obstalces that can prevent meshing

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Geometry and CAD can be very complex, and sometimes the complexity of the model can hinder meshing for FEA. I present three common obstacles and solutions to overcome them.

1) Features and Details

Often features and details can be disregarded in a subsequent structural analysis with FEA.

Threads such as these is an example of how detailed a model can be, but can be disregarded in FEA. In MSC Apex Modeler, we can use the Direct Modeling technology to remove the threads.

Dips or extrusions like these can also be ignored in FEA. MSC Apex Modeler can be used to raise the surface so it is flush with the rest of the surface.

Fillets are not always necessary, and can be easily removed with defeaturing tools such as the one built into MSC Apex Modeler.

2) Extra Edges on solids

Meshers will naturally follow the edges of a solid. If a model has numerous edges, meshers will force elements to follow the edges leading to severely distorted elements. MSC Apex Modeler has a tool that allows you to suppress edges such that they do not conflict with the mesher. This results in meshes that have fewer distorted elements.

In this example, you see the elements are severely distorted, but supress operation hides the edges from the mesher.

3) Spikes through the model

In some scenarios, you may find that a sharp spike is piercing the solid geometry. These spikes are usually unintended, but may be remedied in MSC Apex Modeler as the demo below shows.

The content in this post was orignally inspired by a webinar titled Easy Editing and Repairing Solid Geometry for FEA Meshing by Mica Parks.