The mesh can have a significant impact on the results of an analysis. A mesh that is too fine can lead to unnecessarily long solve times and increased computational costs. In contrast, a mesh that is too coarse may fail to accurately capture important thermal and metallurgical behavior.
Determining the appropriate mesh size is an important part of model development. The optimal mesh depends on the type of analysis, the component geometry, and the physical behavior being modeled. Choosing the right mesh can help achieve accurate results while keeping computational requirements manageable.
Figure 1: Comparison of fine, medium, and coarse mesh for low pressure carburization model
The image above shows how the results of a low pressure carburizing model can differ based on the mesh size at the surface of the part.
Figure 2: Comparison of carbon profile results between the fine and coarse mesh
Based on Figure 2, the coarse mesh shows a significantly higher carbon profile compared to the fine mesh. This difference can be attributed to the averaging of carbon concentration across the nodes within each element. With larger elements, the carbon concentration is averaged over a greater distance. This can spread the calculated carbon concentration farther from the surface and result in a greater predicted carbon penetration depth.
To avoid these issues, it is recommended to perform a mesh convergence study to determine a suitable element size for the part. The goal is to find a mesh that provides consistent and accurate results without unnecessarily increasing computational cost and solve time. While a mesh convergence study requires additional work at the beginning of a project, it can save significant time later. Establishing the appropriate mesh early can help avoid rerunning simulations and provide greater confidence in the final results.