Tutorial: Optimizing Topology - Minimize Mass

Set up a mounting bracket model and run topography optimization to minimize the mass of the bracket.

In this lesson you will learn how to:
  • Create fasteners and define contacts
  • Create local forces in the X and Y directions
  • Create local displacement constraints
  • Define multiple load cases
  • Apply a symmetry plane
  • Run a topology optimization to minimize mass


Open the Mounting Bracket Model

  1. Press F7 to open the Demo Browser.
  2. Double-click the Mounting_Bracket.stmod file to load it in the modeling window.
  3. Set the display units in the Unit System Selector to MMKS (mm kg N s).
  4. Use the right mouse button and the middle mouse button to pan and rotate the view so the mounting bracket is positioned as shown below:


Create Fasteners and Define Contacts

  1. Right-click on the large solid and select Design Space.


    Note: Notice the solid bosses within the larger solid. This model has already been partitioned to facilitate proper loading and connections, which is recommended when running an optimization.
  2. On the Structures ribbon, select the Fasteners tool.


  3. Locations with aligned holes where fasteners can be placed are shown in red. On the guide bar, click the Create All Fasteners button to create fasteners in all of the red locations.
  4. Click Aligned Holes on the guide bar and select Single Holes from the dropdown menu.


  5. In the modeling window, select the four single holes on the 2D plate. Because the holes are single, the fasteners are created as grounded bolts.


  6. Next, select the Contacts tool.


  7. Select the large flat contact between the design space and the plate, then choose Contacting on the microdialog.


  8. Right-click and mouse through the check mark to exit, or double-right-click.

Create Forces in the Local System

  1. Press F2 to open the Model Browser.
  2. Right-click the part named Loading Partition and select Isolate from the context menu.
  3. Right-click System 1 and select Show from the context menu.
  4. Select the Force tool on the Loads icon.


  5. Select the inner surface of the Loading Partition part and enter 1000 N for the force value.


  6. On the microdialog, click the icon and select System 1 from the dropdown menu.


  7. On the microdialog, click X to align the force with the X axis of the local system.
  8. On the Loading Partition part, select the same inner surface to create a second force and enter 2000 N for the force value.


  9. In the microdialog, click the icon and select System 1 from the dropdown menu.
  10. In the microdialog, click the Y button to align the force with the Y axis of the local system.


  11. Right-click and mouse through the check mark to exit, or double-right-click.
    Note: when you are finished with this step, Force 1 will be aligned with local X and have a value of 1000 N and Force 2 will be aligned with local Y and have a value of 2000 N.

Create Displacement Constraints in the Local System

Note: Displacement constraints are typically obtained by running an analysis of the full design space.
  1. Select the Displacement Constraint tool on the Disps icon.


  2. Select the inner surface of the Loading Partition.
  3. In the microdialog, enter 0.8 mm for the displacement constraint.
  4. Click the icon and select System 1 from the dropdown menu.
  5. Click the X button to align the displacement constraint with the X axis of the local system.
  6. Repeat steps 2 - 4 to create a second displacement constraint, then click the Y button to align it with the local system's Y axis.


  7. Right-click and mouse through the check mark to exit, or double-right-click.

Create Load Cases

  1. Select the List Load Cases tool on the Loads icon to open the Load Cases table.
  2. Right-click in the header area of the table and select New Load Case from the context menu to create Load Case 2. You should now have two load cases.
  3. For Load Case 1, ensure that the following items are selected:
    • Displacement Constraint 1
    • Force 1
    • Fastener 7
    • Fastener 8
    • Fastener 9
    • Fastener 10
  4. For Load Case 2, ensure that the following items are selected:
    • Displacement Constraint 2
    • Force 2
    • Fastener 7
    • Fastener 8
    • Fastener 9
    • Fastener 10


  5. Close the Load Cases table.

Add Symmetry Planes

  1. Press the A key to display all. If necessary, press the F key to fit the model in the modeling window.
  2. Select the Symmetric Controls tool on the Shape Controls icon.


  3. Select the Symmetric tool from the secondary ribbon.


  4. Select the bracket in the modeling window. Shape Controls 1 is added to the Shape Controls folder in the Model Browser.




  5. Click the transparent red planes aligned with the Y and Z axes to deselect them.


  6. Right-click and mouse through the check mark to exit, or double-right-click.

Run an Optimization to Minimize Mass

  1. Select the Run Optimization tool on the Optimize icon.


  2. In the Run Optimization window, enter a Name for the optimization run.
  3. Select Minimize Mass for the Objective.
  4. Confirm that the Minimum safety factor is set to 1.5.
  5. Confirm that the Thickness Constraints Minimum is set to 40 mm.


  6. Click Run. A green check mark appears in the Run Status window when the optimization is complete.


    Note: If you don't want to wait for the run to complete, double-click the Mounting_Bracket_run.stmod file in the Demo Browser to open it in the modeling window, then click Show Analysis Results on the Analyze icon to load the results.
  7. In the Run Status window, double-click the name of the run to view the results. The optimized shape is displayed in the modeling window and is listed as an alternative in the Shape Explorer.


  8. Drag the topology slider on the Shape Explorer until all sections are continuous and solid.
You have completed the tutorial.