IS My Mesh Good Enough?

Categories // Simulation, Tips & Tricks

Making mesh adequate and reliable

Written by: Shaun Bentley, Application Engineer

SOLIDWORKS Simulation Mesh

Strictly speaking, there is no rigorous way of knowing for sure that the mesh you have chosen yields a good result, but the following techniques are some of the most popular ways that I have come across for building significant confidence that your mesh is adequate and reliable.

1) Manually Change the Mesh Size with Mesh Control

This method is probably the most straightforward and popular method. Users can test for mesh convergence by making changes to the mesh using a mesh control seen below:SOLIDWORKS Simulation Mesh Control

SOLIDWORKS Simulation Mesh Design Study

and produce a graph like the one shown below to verify that the results stabilize (in this case around 100 MPa):

Simulation Mesh Study Results Graph

2) Plot Energy Norm Error

You can use “Energy Norm Error” plots to pinpoint regions that are not converged. This type of plot can be found in the “Stress plot” Property Manager:

Simulation Energy Norm Error - Stress Plot in Property Manager

The following graphics show a coarse mesh with high energy norm error (left; average = 48%) and the associated stress results (right; max = 82.2 MPa):

SOLIDWORK Simulation Mesh Stress Graphics

Compare this to a scenario with a fine mesh with low energy norm error (left; average = 0.3%) and respective stresses (max = 100 MPa):

Simulation Fine Mesh

More details on energy norm error are shown here, where it states:

SOLIDWORKS Energy Norm Error Details

3) Adaptive Meshing

Adaptive meshing can be turned on for certain models by going to the study properties shown here:

Simulation Study Properties for Adaptive Meshing

The h-adaptive option tends to be more popular since it visually splits elements wherever there are large norm errors. There is no local option for this method, so it can be computationally expensive to run this for many loops. The P-adaptive method is also handy as a convergence check tool, where you may set it to run two loops with the following settings:

Simulation p-Adaptive Meshing Method Options

After running both loops, you should generate an adaptive convergence graph by using the option below:

Create Simulation Adaptive Meshing Convergence Graph

A poor mesh (left) and a good mesh (right) might generate graphs like you see below:

Poor and Good Mesh Graph Examples

If you think these graphs looks similar… LOOK AGAIN! The actual values on the y-axis tell the story of how a slight change in the mesh p-order can produce a large change in the results which tells me the mesh I used to create the graph on the left is dubious.

There are a variety of other tools available to check mesh quality, but the methods above seem to be the most popular.