Method 1: PCB Cooling Channel using Inlet Velocity and Outlet Pressure

Launch HyperWorks

  1. Launch HyperWorks.
  2. In New Session, under HyperWorks select HyperMesh.
  3. For Profile, select OptiStruct.
  4. Click Create New Session.

Import the Model

  1. On the menu bar, select File > Import > HyperMesh Model.
  2. Navigate to and select PCB.hm.
  3. Click Open.

Set Up the Model

Define Material 1

Note: If the model loads outside of the modeling window, press F to fit to window.
  1. In the Model Browser, right-click and select Create > Material.
  2. For Name, enter material1.
  3. For Card Image, select MAT1 from the drop-down menu.
  4. Enter the following material properties:
    1. For E, enter 210000
    2. For NU (Poisson's ratio), enter 0.3.
    3. For RHO, enter 7.85e-09.
  5. Select the MAT4 check box and enter the following properties:
    1. For K (thermal conductivity), enter 44.0
    2. For CP, enter 460000000.
    3. For RHO, enter 7.8e-09.
  6. Click Close.

Define Material 2

  1. In the Model Browser, right-click and select Create > Material.
  2. For Name, enter material2.
  3. For Card Image, select MAT1 from the drop-down menu.
  4. Enter the following material properties:
    1. For E, enter 210000
    2. For NU (Poisson's ratio), enter 0.3.
    3. For RHO, enter 7.85e-09.
  5. Select the MAT4 check box and enter the following properties:
    1. For K (thermal conductivity), enter 44.0
    2. For CP, enter 460000000.
    3. For RHO, enter 7.8e-09.
  6. Select the DARCY check box and enter the following fluid material properties:
    1. KAPPA, enter 0.1.
    2. For MU, enter 1e-09.
    3. For K, enter 0.598.
    4. For CP, enter 4183000000.
    5. For RHO, enter 1e-09.
  7. Click Close.

Define Property 1

  1. In the Model Browser, double-click on Properties to open the Property Browser.
  2. In the browser, select property1.
  3. For Card Image, select PSHELL from the drop-down menu.
  4. For Material, select Unspecified > to open advanced selection.
  5. In the dialog, select material2 from the list.
  6. Click OK.
  7. For T (thickness), enter 0.5.
  8. Click Close.

Define Property 2

  1. In the Property Browser, select property2.
  2. For Card Image, select PSHELL from the drop-down menu.
  3. For Material, select Unspecified > to open advanced selection.
  4. In the dialog, select material1 from the list.
  5. Click OK.
  6. For T (thickness), enter 0.5.
  7. Click Close.

Assign a Property to a Component

  1. In the Model Browser, double-click on Components to open the Component Browser.
  2. In the browser, select auto3.
  3. For Property, select Unspecified > to open advanced selection.
  4. Select property1 from the list and click OK.
    For Material, material2 is auto-selected. If material2 is not selected, you can choose it using advanced selection.

Apply Loads and Boundary Conditions

Create Thermal Loading

  1. In the Property Browser, right-click on property2 and select Isolate.
  2. In the Model Browser, Create > Group.
  3. For name, enter group1.
  4. For Card Image, select CONDUCTION.
  5. For Secondary Entity IDs, select the elements of property2.
  6. Click OK.


    Figure 1.

Apply Heat Flux

  1. From the menu bar select the Analyze ribbon.
  2. On the ribbon, select the Flux tool.


    Figure 2.
  3. On the displayed panel, select elements > by group.
  4. Select the group1 check box and click select.
  5. For value, enter 10.0.
  6. For relative size, enter 100.0.
  7. Click create.
  8. Click return.

Create the Inlet Node Set

  1. In the Model Browser, right-click and select Create > Set.
  2. For name, enter inlet.
  3. For Card Image, select SET_GRID from the drop-down menu.
  4. For Entities, select nodes 131 to 151 as shown in Figure 3.


    Figure 3.

Create the Outlet Node Set

  1. In the Model Browser, right-click and select Create > Set.
  2. For name, enter outlet.
  3. For Card Image, select SET_GRID from the drop-down menu.
  4. For Entities, select nodes 191 to 211 as shown in Figure 4.


    Figure 4.

Assign Thermal Boundary Conditions

  1. From the menu bar select the Analyze ribbon.
  2. On the ribbon, select the Temp Loads tool.


    Figure 5.
  3. From the displayed panel, click nodes > by set and select inlet (nodes 131 to 151).
  4. For value, enter 0.0.
  5. For relative size, enter 100.0.
  6. For load types, select SPC.
  7. Click create.
  8. Click return.

Create Inlet Velocity

  1. In the Model Browser, right-click and select Create > Load Collector.
    A default load collector displays in the Entity Editor.
  2. For Name, enter auto2.
  3. Close the window.
  4. In the Load Browser, right-click and select Create > Flow Velocity > INLETVL.
  5. For ELSETID, select Unspecified > to open advanced selection.
  6. In the dialog, select inletvel (SURF set).
  7. For Value, enter 50.0.


    Figure 6.

Create Outlet Pressure

  1. In the Component Browser, right-click on auto1 and select Make current from the context menu.
  2. In the Model Browser, Create > Load.
  3. For Load type, select SPCP.
  4. For GSETID, select Unspecified > to open advanced selection.
  5. In the dialog, select outlet from the list.
  6. For D, enter 0.1.
  7. Click Close.

Create a Subcase

  1. In the Model Browser, right-click and select Create > Load Step.
  2. For Name, enter CPU loading.
  3. For Analysis Type, select Heat Transfer (Steady State) from the drop-down menu.
  4. For the following selections, use Unspecified > to open advanced selection.
    1. For SPC, specify auto1.
    2. For LOAD, specify auto1.
    3. For SPCP, specify auto1.
    4. For INLTVEL, specify auto2.
  5. Click Close.

Set Up the Optimization

Create the Topology Design Space

  1. On the menu bar, select the Optimize ribbon.
  2. On the ribbon, select Topology.


    Figure 7.
  3. For Name, enter designvar.
  4. For Property Type, select PSHELL from the drop-down menu.
  5. From List of Properties, select Unspecified > to open advanced selection.
  6. In the dialog, select property1.
  7. Under Parameters, For Mindim, enter 5.0.
  8. Click Close.

Create Responses

  1. On the menu bar, select the Optimize ribbon.
  2. On the ribbon, select Responses.


    Figure 8.
  3. For Name, enter VOLFRAC.
  4. For Response Type, select volumfrac from the drop-down menu.
  5. Click Close.
  6. Create a second response.
    1. For Name, enter tcomp.
    2. For Response Type, select thermal compliance from the drop-down menu.
  7. Create a third response
    1. For Name, enter pressure.
    2. For Response Type, select flowpres from the drop-down menu.
    3. For List of Nodes, select the nodes of the inlet (nodes 131 to 151).
  8. Create a fourth response.
    1. For Name, enter average.
    2. For Response Type, select function from the drop-down menu.
    3. For Function, select avg from the drop-down menu.
    4. For Response List, select Optimization Responses > to open advanced selection.
    5. In the dialog, choose pressure and click OK.
  9. Click Close.

Create the Objective

  1. On the menu bar, select the Optimize ribbon.
  2. On the ribbon, select Objectives.


    Figure 9.
  3. For Objective Type, select Minimize.
  4. For Response Id, select Unspecified > to open advanced selection.
  5. In the dialog, select tcomp.
  6. For Loadstep Id, open advanced selection and choose CPU loading.

Create Constraints

  1. On the menu bar, select the Optimize ribbon.
  2. On the ribbon, select Constraints.


    Figure 10.
  3. For Name, enter volconst.
  4. For Response, select Unspecified > to open advanced selection.
  5. In the dialog, select VOLFRAC.
  6. For Lower Options, select Lower Bound from the drop-down menu.
  7. In the Lower Bound text box, enter 0.8.
  8. Create another constraint.
    1. For Name, enter presConst.
    2. For Response, open advanced selection and choose average.
    3. For List of Loadsteps, open advanced selection and choose CPU loading.
    4. For Upper Options, select Upper Bound from the drop-down menu.
    5. In the Upper Bound text box, enter 0.1002.
  9. Click Close.

Run the Optimization

  1. From the Analysis page, click OptiStruct.
  2. Click save as.
  3. In the Save As dialog, specify location to write the OptiStruct model file and enter PCB for filename.
    For OptiStruct input decks, .fem is the recommended extension.
  4. Click Save.
    The input file field displays the filename and location specified in the Save As dialog.
  5. Set the export options toggle to all.
  6. Set the run options toggle to optimization.
  7. Set the memory options toggle to memory default.
  8. Click OptiStruct to run the optimization.
    The following message appears in the window at the completion of the job:
    OPTIMIZATION HAS CONVERGED.
FEASIBLE DESIGN (ALL CONSTRAINTS SATISFIED).
    OptiStruct also reports error messages if any exist. The file PCB.out can be opened in a text editor to find details regarding any errors. This file is written to the same directory as the .fem file.

View the Results

  1. In the Solver window, select Results to open the results in HyperView.
  2. HyperView, select Contour .
  3. In the first drop-down menu, for Results Type, select Element Densities.
  4. Click Apply.
    Figure 11.