HM-3100 - AutoMesh PDF
HM-3100 - AutoMesh PDF
HM-3100 - AutoMesh PDF
The optimal starting point for creating a shell mesh for a part is to have geometry surfaces
defining the part. The most efficient method for creating a mesh representing the part
includes using the Automesh panel and creating a mesh directly on the part’s surfaces.
This exercise uses the channel.hm file, which can be found in the hm.zip file. Copy the file from this directory to your
working directory.
In this step you will open and view the model file, channel.hm.
2. From the menu bar, click File > (and then) Open > (and then) Model.
4. Observe the model using the different visual options available in HyperMesh (rotation, zooming, etc.).
In this step you will mesh part surfaces all at once using an element size of 5 and mixed
element types, quads and trias.
1. To open the AutoMesh panel, click Mesh > (and then) Create > (and then) 2D AutoMesh from the menu bar,
or press F12.
2. Go to the size and bias subpanel.
9. Click mesh.
HyperMesh opens the density subpanel in the meshing module. The model displays a node seeding and a
number on each surface edge.
Note: The number displayed in the graphics area is the number of elements that were created along the
edge.
At this point, you could be done using the Mesh panel to mesh the part. The mesh quality is very good.
However, you will remain in the meshing module to perform the next steps, which demonstrate how to use
various subpanels to interactively control the creation of the mesh.
1. To open the Delete panel, click on the Collectors toolbar, or press F2.
In this step you will mesh the surface having three fixed points interior to its surface.
2. Select the surface that has three fixed points interior to its surface as indicated in the following image.
Figure 1.
3. Click mesh.
HyperMesh opens the meshing module.
In this step you will fit the surface to the graphics area.
To fit the surface to the graphics area, click f or click local view >> fill in the density subpanel.
In this step you will specify a new element density along surface edges.
◦ Left-click on the edge's element density number to increase it by one, or right-click on the element's
density number to decrease it by one, or
◦ Click and hold the mouse pointer on the edge's element density number and drag your mouse up to
increase the number or down to decrease the number.
Figure 2.
3. Click mesh.
HyperMesh updates the preview mesh based on the change.
Figure 3.
In this step you will specify a new element density along surface edges.
Figure 4.
4. Click mesh.
HyperMesh updates the preview mesh based on the change.
Figure 5.
6. Click mesh.
HyperMesh updates the preview mesh based on the change.
In this step you will specify a new element size to adjust element densities along surface
edges.
3. Select the element density number of the edge indicated in the following image to calculate it based on an
element size of 7 .
HyperMesh calculates the new number to create elements as close as possible to 7.
Figure 6.
4. Click mesh.
HyperMesh updates the preview mesh based on the change.
Figure 7.
Figure 8.
In this step you will change all edge element densities to reflect the initial element size of 5.
3. Click mesh.
HyperMesh updates the preview mesh based on the change.
4. To accept the mesh and go back to the size and bias subpanel, click return.
You should still be in the Mesh panel, size and bias subpanel.
1. With the entity selector active and set to surfs, select the rib surface in the middle of the part as indicated in
the following image.
Figure 9.
3. Click mesh.
HyperMesh opens the meshing model and generates the preview mesh.
4. To fit the rib's surface to the graphics area, click local view >> rear.
Figure 10.
Step 11. Check the Mesh Quality
In this step you will check the quality of the rib's preview mesh.
2. To identify all of the elements that have an aspect ratio greater than 5, click aspect.
None of the elements fail the check, and the status bar reads, "Maximum aspect ratio found is equal to 1.75".
4. To identify all of the elements that have a jacobian less than 0.8, click jacobian.
HyperMesh identifies several elements that fail the check and outlines them in red. The status bar reads,
"Minimum jacobian found is equal to 0.75."
Figure 11.
5. Verify that none of the elements have a jacobian less than 0.7.
7. Click min angle. The minimum interior angle found among all the quad elements is 46.46.
9. Click max angle. The maximum interior angle found among the quad elements is 136.58.
Step 12. Change the Rib Mesh Pattern
In this step you will change the rib's mesh pattern by changing the mesh method used for its
surface.
1. Go to the mesh style subpanel. The edge's element density numbers have disappeared, and there is now a
small icon interior to the rib's surface. This icon indicates that HyperMesh is currently using the free
(unmapped) mesh method to mesh the surface.
Figure 12.
Figure 13.
In this step you will check the quality of the rib's preview mesh again.
2. Check for elements having an aspect ratio greater than 5. What is the highest value reported?
3. Check for elements having a jacobian less than 0.7. What is the lowest value reported? In this case, the free
(unmapped) mesh has a better jacobian than the map as rectangle mesh.
4. Check for quad elements having a min angle less than 45. What is the smallest value reported?
5. check for quad elements having a max angle greater than 135. What is the highest value reported?
In this step you will change the rib's mesh method back to free (unmapped).
4. Click mesh.
HyperMesh updates the preview mesh based on the change.
5. To accept the mesh as final and go back to the Mesh panel, click return.
In this step you will preview a mesh of all displayed, unmeshed surfaces.
You should still be in the Mesh panel, size and bias subpanel.
3. Click failed.
The status bar reads, "There are no surfaces with meshing errors."
Note: This is correct. All surfaces you selected to mesh so far have a mesh on them.
5. Click mesh.
HyperMesh opens the meshing module and generates the preview mesh.
Figure 14.
In this step you will change the element type for some surfaces to trias.
1. Go to the mesh style subpanel.
3. Under elem type, use the switch to change the mesh type to trias.
5. On the two surfaces indicated in the following image, left-click on to set their element type to trias ( ).
Figure 15.
6. Click mesh.
HyperMesh updates the preview mesh based on the change.
Figure 16.
In this step you will adjust the node spacing on surface edge (biasing).
1. Go to the biasing subpanel. The bias intensity number on each surface edge is 0.000, which is the default
number.
Note: This style corresponds to the positive slope of a straight line over the interval [0,1] of the real line.
For a positive bias intensity, smaller elements are at the start of the edge.
4. To change the biasing intensity number of the edge indicated in the following image from 0.0 to 3.0:
◦ Left-click on the edge’s biasing intensity number to increase it by 0.1, or right-click on the edge's
biasing intensity number to decrease it by 0.1, or
◦ Click and hold the mouse pointer on the edge’s biasing intensity number and drag your mouse up to
increase the number or down to decrease the number.
Figure 17.
5. Click mesh.
HyperMesh updates the preview mesh based on the change.
Figure 18.
9. Click mesh.
HyperMesh updates the preview mesh based on the change.
10. Set the bias style to bellcurve. This bias style distributes nodes along the edge in a pattern that is symmetric
across the midpoint of the edge.
Note: For a positive biasing intensity, the smaller elements are at the start and end of the edge.
12. On the same edge, click to change it from the linear bias style to the bellcurve ( ) bias style.
14. To accept the final mesh and go back to the Mesh panel, click return.
In this step you will remesh the channel's bottom two surfaces.
You should still be in the Mesh panel, size and bias subpanel.
Note: This mode is not interactive, therefore it does not take you to the meshing module. Rather, it
meshes surfaces using only the basic parameters of the AutoMesh panel. Use Interactive mode to remesh the
surfaces if you require the different options to control the created mesh.
Figure 19.
4. In the element size= field, type 10 .
5. Click mesh.
HyperMesh deletes the existing mesh on the selected surfaces and creates a new mesh.
Note: Connectivity was maintained with the surrounding, smaller mesh. This is because the break
connectivity option was not used.
Optional: From the menu bar, click File > (and then) Save > (and then) Model.