5 Working With Loads On Geometry
5 Working With Loads On Geometry
5 Working With Loads On Geometry
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HyperWorks Tutorials
Modify the mesh and remap the loads to the new mesh
Step 2: Create three load collectors for constraints, forces, and pressure loads.
1. In the Model Browser, right-click in the white space of the browser list and click Create > LoadCollector.
2. In the Name: field, type constraints.
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3. Select a color.
4. For Card image: select none.
5. Click Create.
6. Similarly, create two more load collectors with names pressure and forces, assign colors to them, and select
no card images.
Different boundary conditions can now be created.
Defining loads and boundary conditions on geometry.
You can apply loads to geometric entities in a way similar to the manner in which loads are applied to mesh by
using the following panels from the Analysis page: forces, moments, constraints, pressures, and
temperatures.
In this step, you will apply constraints, pressure, and forces to geometric entities in the model. Constrain the
bottom portion of the c-channel using line data. Then create pressure loads on the top surfaces. Finally, add
forces at the eight corners of the surfaces defining the top of the c-channel (see following image).
Step 3: Fully constrain the bottom eight lines of the c-channel using the constraints
panel from the Analysis page.
1. In the Model Browser right-click the constraints load collector and pick Make Current.
2. From the menu bar select BCs > Create > Constraints to open the Constraints panel.
3. Select the create subpanel.
4. Set the entity selector to lines.
5. Select the eight lines defining the bottom portion of the c-channel.
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Lines to constrain
Step 4: Apply a pressure of 25 units normal to the top three surfaces using the
pressures panel.
1. Set pressure as your current load collector by right-clicking it in the Model browser and selecting Make
Current.
2. From the menu bar select BCs > Create > Pressures to open the Pressures panel.
3. Select the create subpanel.
4. Set the entity selector to surfs and pick the three surfaces defining the top of the c-channel.
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Step 5: Create forces at the eight corners of the three top surfaces.
1. In the Model Browser, set the current load collector to forces.
2. From the menu bar select BCs > Create > Forces to open the Forces panel.
3. Select the create subpanel.
4. Set the entity selector to points and select the eight fixed points defining the corners of the c-channels top
surfaces.
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Loads on geometry
Note:
If you sent some loads into the wrong load collector, use the Organize panel on loads to move them
into the right collector.
In this section you created various types of loads on various geometric entities: lines, surfaces and fixed point.
The ultimate goal is to have these loading conditions applied to finite elements. You will now create these
elements.
).
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Meshed c-channel
In this step, you quickly created a shell mesh on the surfaces. You can now try to map the loads that were applied
to geometric entities onto these finite elements.
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Left-click the geometry display buttons in your Model Browser so your component display changes from
this:
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to this:
.
2. From the menu bar select File > Export > Solver Deck.
3. Click the arrows (
4. Set Export: to Displayed, and export the model to your working directory as an OptiStruct deck.
Since loads applied to geometry were turned off in the Model Browser previously, only the loads mapped
previously will be exported. You may open the exported deck in any text editor to verify that no RADIOSS
FORCE card has been exported in the deck.
5. Specify a file name.
6. Click Export to export the file.
In this section you experimented with the behavior of the Export panel when it comes to loads applied to
geometry and elements. You learned that with different combinations of the all/displayed option and loads
displayed in the Model Browser, you can control what information gets exported.
Step 9: Modify the mesh and remap the loads to the new mesh.
Besides the convenience they offer, loads applied to geometry give you the flexibility of re-applying them as many
times as you want to different meshes. This feature is particularly useful when remeshing a model without deleting
complicated loads or boundary conditions. After remeshing, loads or boundary conditions that have been applied
to geometrical entities can be easily remapped to the new mesh, while loads applied to elements are
automatically deleted when the elements themselves are deleted.
In this step, remesh the surfaces and remap the loads on geometry to the new mesh.
1. Go to the Automesh panel.
2. Click surfs and select displayed.
3. For element size =, enter the value 0.5.
4. Leave all other options used earlier unchanged.
5. Click mesh.
The automesher deletes the existing elements before creating a completely new set based on the new
element size. As you exit the Automesh panel, the loads that were applied to the initial mesh are removed
since the elements are no longer there.
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New mesh
Step 10: Map all the loads on geometry to the new mesh using the load on geom panel.
1. From the menu bar select BCs > Loads on Geometry panel.
2. Click loadcols and check the boxes next to constraints, pressure, and forces.
3. Click select.
4. Click map loads.
The loading conditions initially defined for the geometric entities are now applied to the new mesh. The
various loading conditions are placed into the same load collector as the corresponding ones applied to the
geometry. Note that you did not have to display these loads to map them.
Note:
Deleting geometric entities to which loads are applied will also result in the deletion of these
loads. It will not affect any loads applied to the mesh, though.
In this step, you experimented with the remapping of loads applied to geometry onto a new mesh. Loads applied
on geometric entities can be mapped several times onto the different finite element entities attached to these
geometric entities. You took advantage of this in a situation where a mesh had to be changed, and it saved you
from having to recreate loads on the elements.
Summary
In this tutorial, you used several boundary condition creation panels to generate constraints and various loading
conditions on geometric entities. You then experimented with the mapping of these loads on geometry onto finite
elements. You also familiarized yourself with the rules that govern the export of loads on geometric entities.
No consideration to the creation of specific card images that need to accompany the various loading conditions
was given. For more information on how to generate the various loading conditions for different solvers, refer to
the Modeling / Solver Specific section of the HyperMesh tutorials.
Go to HyperMesh Tutorials.
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