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

Launch HyperMesh

  1. Launch HyperMesh.
  2. In the New Session window, select HyperMesh from the list of tools.
  3. For Profile, select OptiStruct.
  4. Click Create Session.
    Figure 1. Create New Session


    This loads the user profile, including the appropriate template, menus, and functionalities of HyperMesh relevant for generating models for OptiStruct.

Import the Model

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

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.
    Figure 2. Create Material 1


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.
    Figure 3. Create Material 2


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.
    Figure 4. Define Property 1


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.
    Figure 5. Define Property 2


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.
    Figure 6. Assign Property


Apply Loads and Boundary Conditions

Apply Heat Flux

  1. From the menu bar select the Analyze ribbon.
  2. On the ribbon, select Heat Flux.
    Figure 7. Select Heat Flux


  3. For ELSETID click Unspecified > Create to create a SURF set.
    Figure 8. Create Heat Flux Load


  4. Choose elements of property2.
  5. Set the Q0 field to 10.0.
  6. Click OK and Close.

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 9.
    Figure 9. Inlet Nodes


    Figure 10. Create Inlet Node Set


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 11.
    Figure 11. Outlet Nodes


    Figure 12. Create Outlet Node Set


Assign Thermal Boundary Conditions

  1. From the menu bar select the Analyze ribbon.
  2. On the ribbon, select the Temp Loads tool.
    Figure 13. Select Temperature Load Tool


  3. From the dialog, click nodes > and select by set.
  4. Select inlet (nodes 131 to 151).
  5. For load types, select SPC.
  6. For value, enter 0.0.
  7. Click Create and Close.

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 > INLTVEL.
    Figure 14. Create Inlet Velocity


  5. For ELSETID, select Unspecified > to open advanced selection.
  6. In the dialog, select inletvel (SURF set).
  7. For Value, enter 50.0.
    Figure 15. Define Inlet Velocity


    Figure 16. Inlet Velocity


Create Outlet Pressure

  1. In the Model Browser, Create > Load.
  2. For Load type, select SPCP.
  3. For GSETID, select Unspecified > to open advanced selection.
  4. In the dialog, select outlet from the list.
  5. For D, enter 0.1.
  6. 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 auto2.
    4. For INLTVEL, specify auto2.

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 17. Select Topology


  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.
    Figure 18. Create Design Variable


Create Responses

  1. On the menu bar, select the Optimize ribbon.
  2. On the ribbon, select Responses.
    Figure 19. Select Response


  3. For Name, enter VOLFRAC.
  4. For Response Type, select volumefrac from the drop-down menu.
    Figure 20. Create Optimization Response
  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).
      Figure 21. Create Third Optimization Response


  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 22. Select Objectives


  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.
    Figure 23. Create Objective


Create Constraints

  1. On the menu bar, select the Optimize ribbon.
  2. On the ribbon, select Constraints.
    Figure 24. Select Constraints


  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.
    Figure 25. Create Optimization Constraints


  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.
      Figure 26. Create Second Optimization Constraint


  9. Click Close.

Submit the Job

Run OptiStruct.

  1. From the Analyze ribbon, click Run OptiStruct Solver.
    Figure 27. Select Run OptiStruct Solver


  2. Select the directory where you want to write the OptiStruct model file.
  3. For File name, enter PCB.
    The .fem filename extension is the recommended extension for Bulk Data Format input decks.
  4. Click Save.
  5. Click Export.
  6. For run options, toggle optimization.
  7. In the Altair Compute Console, click Run.
    If the job is successful, an "ANALYSIS COMPLETED" message appears in the Compute Console Solver View Message Log. New results files are in the directory where the model file was written. The PCB.out file is a good place to look for error messages that could help debug the input deck if any errors are present.

View the Results

  1. Open the results in HyperView.
  2. HyperView, select Contour .
  3. In the first drop-down menu, for Results Type, select Element Densities (v).
  4. Click Apply.
    Figure 28. Contour Plot for Element Densities and Grid Temperatures