When you use numerical simulations, the accuracy of the results depends on the quality of the mesh. In other words, a “poor” mesh will lead to inaccurate results. Therefore, it’s crucial to ensure that the mesh is good enough to produce reliable results.
There are various ways to verify that a mesh is acceptable. One of them is to conduct a mesh independence study, which you can learn more about in this article.
However, a mesh independence study requires a lot of time and multiple models with different meshes and results. Additionally, it’s usually best to perform the study for isolated regions of the model rather than taking a global view.
Luckily, ANSYS provides several tools to measure the overall mesh quality during and after the mesh generation phase.
To access these tools, go to Mesh → Statistics → Mesh Metric, and you will see a drop-down menu like the one in the image below.
You can choose from different mesh metrics, and ANSYS will provide you with mesh statistics for the selected metric. If you need more information on these metrics, you can read this article on mesh metrics.
I will only mention two of the most commonly used metrics – Skewness and Orthogonal Quality. ANSYS has literature that can provide helpful guidelines for all mesh metrics, including these two.
Low orthogonal quality and high skewness values are generally not recommended, as shown in some ANSYS training materials. These metrics vary from 0 to 1, and the recommendations are mainly for meshes used in CFD applications. However, they can also be used for structural models to achieve a high-quality mesh.
Below is a link for ANSYS training material which goes into more details on the topic of meshing.
If you want to make sure that the mesh generated meets the specific requirements for the physics being modeled, you can activate automatic shape checking in ANSYS Workbench. Simply go to Mesh, Quality, Check Mesh Quality, and choose an option from the drop-down menu.
The options are No, Yes with Errors and Warnings, and Yes with Errors. If you choose Yes, then the meshing algorithm will ensure that the mesh meets the specific requirements for the physics being modeled.
The ANSYS Meshing User’s Guide presents the shape checking limit criterion for each option. If the results of any test are outside of the limits shown, the mesh will fail. For example, a Jacobian ratio greater than 40 computed at element nodal points will cause a mesh failure when using the Aggressive Mechanical option.
It’s important to note the differences between Standard Mechanical Shape Checking and Aggressive Mechanical Shape Checking. The aggressive option is more stringent and ensures a higher quality mesh than standard mechanical shape checking. This option is especially recommended for models with non-linear materials and plasticity modeling.
For more detailed information on meshing, check out this ANSYS training material. With these tips, you’ll be able to verify the quality of your mesh in no time!