Introduction
This is English translation of this article.
HyperMesh and MVD (Model Verification Director) provide shape-comparison functionality. Thus, we can compare CAD and FEM. However, comparison between grids and CAD/FEM are not supported. I considered how I can compare them. And finally, I realized that Radioss have already had a future with which Radioss can measure dictance between grids and FEM faces. The function is interface. Thus, I decided to use Radioss for this purpose. I write my test record here.
Example
Challenge
The example CAD and grids data is shown in the next figure. The blue one is the mesh on the CAD. When I meshed on the blue CAD, I carefully kept all nodes on the CAD surfaces. I did not use any meshing method by which a generated node can be off the CAD. The mesh quality is not important. Keeping all nodes on the CAD faces is the most important.
In HyperMesh, Rigid Body Mesh might be the best one for this purpose,
Around this region, there are difference between the grid and the CAD faces. The aim of this example is to find this.
In this article, we assume that the difference over 0.1mm is NG and will figure out the NG region.
Radioss Model
Download:
- SPH particles are added on the scanned grids. The material and the property are not important. Just avoiding syntax error is OK because we do not do real simulation. If unsure, you might be able to use the /MAT/ELAST and /PROP/SPH in the example model.
- The material and the shell property of the mesh on the CAD are also not important because we do no do real simulation. If unsure, you might be able to use the /MAT/VOID and /PROP/VOID in the example model.
- The tied interface, /INTER/TYPE2 is applied between the SPH grids and the shell mesh. The search distance is set to 0.1mm.
Once we run the starter, we can see the following warning and node list in the _0000.out file. The listed nods are placed over 0.1mm faraway from the shell mesh.
Post Processing
We have already obtained the target grid IDs. Now, we will review it on HyperMesh.
There might be some methods to do this. I createe a Radioss node group from the node ID list, and included the node group to the main input file.
Download the model
You can review the node group in HyperMesh,
Unfortunately, there is no official tool to generate the node group from the _0000.out file. You need to do it in your favorite texteditor or some sort of program. If you cannot but want to do it, you can ask the Siemens/Altair account manager of your organization. to develop a program for this.
Video
