Tutorial: Tet-Dominant Mesh Algorithm

This article provides a step-by-step meshing tutorial using the Tet-dominant algorithm. The geometry is a bearing block, which will be meshed using different refinement strategies.

tet-dominant mesh tutorial with simscale documentation — Figure 1: Tet-dominant mesh of the bearing block.

Overview

This meshing tutorial teaches how to:

Create meshes using the Tet-dominant algorithm.
apply different types of local refinements.
create topological entity sets in SimScale.

Note

The usual workflow in SimScale is the following:

Preparing the CAD model for the simulation;
Setting up the simulation;
Creating the mesh;
Run the simulation and analyze the results.

Since this is a meshing tutorial, it will fully focus on the third step.

1. Prepare the CAD Model and Select the Analysis Type

First of all click the button below. It will copy the tutorial project containing the geometry into your own workbench.

Import tutorial into workbench

The following picture demonstrates what should be visible after importing the tutorial project.

bearing block geometry in a static analysis — Figure 2: Imported CAD model of a bearing block in the SimScale workbench.

1.1 Getting Started

After importing a geometry into the workbench, the first step is to click on the geometry to start setting up the simulations.

1.2 Create the Simulation

creating a new simulation — Figure 3: Creating a new simulation.

Hitting the ‘Create Simulation’ button leads to the following options:

library of analysis types available within simscale — Figure 4: Analysis types available in SimScale.

Choose Static as the analysis type and Create the Simulation.

As this tutorial explains how to mesh, we will overstep the simulation setup, and proceed directly to the meshing.

2. Mesh

The Tet-dominant meshing tool will be used to mesh the bearing block. A total of 3 different meshes will be created, making use of different refinement techniques.

With local refinements, the goal is to achieve a better resolution of the fillets. Make sure to check this documentation page for the Tet-dominant algorithm settings.

2.1 First Mesh: Automatic Sizing

To create a mesh, click on Mesh in the simulation tree. A tab with options will open. Change the Algorithm to Tet-dominant.

For the first mesh, sizing will be fully automatic, as shown below:

tet-dominant settings for a bearing block geometry — Figure 5: Tet-dominant settings for the first mesh. Cell sizing is completely automatic.

The resulting mesh will have about 137K cells and look like this:

tetrahedral mesh using default settings — Figure 6: Tet-dominant mesh using automatic sizing. Fineness was set to coarse.

This mesh shows a reasonable discretization of the geometry. However, some parts such as the small radii are not represented accurately in every detail. The number of layers in the radii is only 2.

For the second mesh, a local element size refinement will be applied to the fillets.

Before jumping into the mesh settings, let’s create a topological entity set for the fillet faces. With topological entity sets, the user can select a predefined group of faces in a single click.

In order to create a topological entity set for the fillets, please follow the steps below:

Select all 14 fillet faces;
In the right-hand side panel, click on the ‘+ button’ next to Topological Entity Sets;
Name the newly created set appropriately, e.g. “Fillets”.

creating a topological entity set to quickly select a group of faces — Figure 7: Creating a topological entity set. Groups of faces can be selected in the right-hand side panel.

Proceed as below to create and set up the second mesh.

creating a new tet-dominant mesh — Figure 8: Steps to create a new mesh.

The main settings for the second mesh are exactly the same from the first one.

main settings for the second tet-dominant mesh — Figure 9: Main settings for the second Tet-dominant mesh.

Now, next to Refinements, click on the ‘+ button’ and create a Local element size refinement. This refinement allows the user to specify different refinement settings to the desired faces.

local element size refinement being applied to fillets — Figure 10: Local element size refinement. The user can specify different fineness levels to desired faces.

The second mesh is ready to be generated. After completion, it will be just short of 205k cells. Due to the local refinement, fillets are more accurately captured.

bearing block geometry with a local refinement for the fillets — Figure 11: The second mesh. The resolution within the fillets has improved.

2.3 Third Mesh: Manual Sizing

The third mesh will have manual sizing, to improve the fillets’ discretization even further. Please create a new mesh and set it up as below:

manual sizing for a tet-dominant mesh — Figure 12: Tet-dominant mesh using manual sizing.

The result is a mesh with around 119k cells. Cell density on the fillets is higher than in the previous meshes.

tet-dominant mesh with manual sizing — Figure 13: Third mesh, showing a good discretization of fillets.

3. Comparing the Meshes

Now that the three meshes are ready, we can compare them side-by-side. The picture below shows a comparison of the meshes, focusing on the fillets.

highlight of fillets using different refinements in the tet-dominant meshes — Figure 14: Comparing the discretization of fillets.

Coarse mesh with automatic cell sizing;
Coarse mesh with moderate local refinement on the fillets;
Manual mesh sizing.

Congratulations! You have finished the Tet-dominant meshing tutorial!

Have a look at the finished project

Note

If you have questions or suggestions, please reach out either via the forum or contact us directly.

Last updated: May 8th, 2020

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Documentation

Tutorial: Tet-Dominant Mesh Algorithm

Overview