Meshing Components using Batch-Mesh Technique

Meshing Sheet Metal Components using Batch-Mesh Operation

Objective:

To mesh sheet metal components of simple geometry using batch-mesh technique, for the specified criteria and assign non-linear material to the meshed elements (switching to Radioss profile).

Procedure:

Step 1. Open the Hypermesh in Radioss user profile mode, and import the given geometry (provided STEP or IGES files).

Step 2. Now to perform batch mesh operation, we require two files.

• Parameter file (.PARAM) - This file contains all the information and specifications to perform the surface cleanup and topology repair.
• Criteria file (.CRITERIA) - This file has all the meshing specifications and the quality criterion parameters to perform meshing.

These two files are then created as per the required specifications by selecting the appropriate options and by feeding specified quality criteria values and topology repair parameters. The created files are then saved so that they can be reused for the other model also.

Step 3. Now after importing the geometry, the solids are deleted and the batch-mesh operation is performed for one component after another, by just selecting the surfaces of the components to be meshed and feeding the created parameter and criteria files.

Step 4. Once the time-consuming automatic process is done, the midsurface and the mesh are generated.

The mesh generated for the hood and fender geometry are shown in the respective snapshots.

Step 5. The extracted midsurface however is not perfect and may have some issues (like in the figure below) and discrepancies and this can lead to element failure in meshes. These issues needs to be repaired manually to avert any geomtrical discrepancies or element failure.

Step 6. The regular custom normal, free edge, equivalence and node dependency checks are done. Once the element failure and other errors are rectified, appropriate thickness of the component needs to be assigned to the mesh elements. Switch to 2D detailed representation view, to visualise and verify the thickness assigned to the mesh elements.

Step 7. To assign non-linear material property to the elements, switch to Radioss user profile. And the material card is then created with the provided non-linear material paramters such as different stress values and other material property parameters.

Result:

The elements were meshed by batch-mesh method with the specified meshing requirement criteria and no element failure is ensured, also respecting and adhering to the best practices.

The mesh obtained has a high concentration of tria elements and multiple instances of opposite trias are also seen, which can be easily cleared by manual cleanup processes.

The mesh obtained for hood components have a 1.7% tria element percentage and zero element failure.

The fender component mesh has a tria percentage of 4.6% and no element failure.