WS4-1 WORKSHOP 4 FORCED AIR CONVECTION FROM PRINTED CIRCUIT BOARD NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation

WS4-2 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation

WS4-3 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation n Problem Description Use the previous model of the PCB with the three chips, except replace the free convection with forced convection. The forced convection is modeled using coupled advection convection. The temperature dependency of the convection coefficient will be defined using a temperature dependent field. The air temperature rises as the air traverses the circuit board.

WS4-4 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation

WS4-5 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation n Suggested Exercise Steps 1. Create a new database called forced_conv_pcb.db 2. Set solver to MSC.Nastran Thermal 3. Create surfaces for subsequent extrusion 4. Extrude the surfaces to create the solids 5. IsoMesh the solids 6. Connect the finite elements 7. Check for element free edges 8. Specify material 9. Define element properties 10. Define temperature dependent field 11. Create a curve 12. Create curve at the air stream

WS4-6 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation n Suggested Exercise Steps (Continued) 13. Mesh Curve 2 at the air stream 14. Specify material to represent air 15. Create flow tubes to represent the flowing air 16. Create coupled advection for flow stream 17. Apply heat flux 18. Define the inlet temperature 19. Perform the thermal analysis 20. Attach the results file 21. Display the temperature results 22. Quit MSC.Patran

WS4-7 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 1: Create New Database Create new data a.File: New b.Enter forced_conv_pcb.db for File name. c.Click Ok. c a b

WS4-8 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 2: Set solver to MSC.Nastran Thermal Change the tolerance a.Select Default for Tolerance. b.Select MSC.Nastran for Analysis Code. c.Select Thermal for Analysis Type. d.Click OK. c a b d

WS4-9 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 3: Create Surfaces for Subsequent Extrusion Create the surfaces representing the printed circuit board. a.Geometry: Create/Surface/XYZ b.Enter for Vector Coordinates List. c.Enter [0 0 0] for Origin Coordinates List. d.Click Apply. e.Enter for Vector coordinates List. f.Enter [1 1 0] for Origin Coordinates List. g.Click Apply. h.Enter for Vector Coordinates List. i.Enter [ ] for Origin Coordinates List. j.Click Apply. k.Enter for Vector Coordinates List. l.Enter [4 4 0] for Origin Coordinates List. m.Click Apply. c a b j i g h f d e m l k

WS4-10 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 4: Extrude the Surfaces to Create the Solids Extrude the solid a.Geometry: Create/Solid/Extrude. b.Click IsoMeshable icon for Solid Type. c.Enter [0 0 0] for Origin of Scale and Rotate. d.Enter for Translation Vector. e.Enter Surface 1 for Surface List. f.Click Apply. g.Enter for Translation Vector. h.Enter Surface 2:4 for Surface List. i.Click Apply. c a b i g h f d e

WS4-11 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 5: IsoMesh the Solids Mesh the solids to create Hex8 element a.Elements: Create/Mesh/Solid. b.Select Hex for Elem Shape. c.Select IsoMesh for Mesher. d.Select Hex8 for Topology. e.Enter Solid 1:4 for Solid List. f.Enter 0.25 for Value of Global Edge Length. g.Click Apply c a b g f d e

WS4-12 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 6: Connect the Finite Elements Equivalence the nodes to connect the elements a.Elements: Equivalence/All/Tolerance Cube. b.Enter for Equivalencing Tolerance. c.Click Apply. c a b

WS4-13 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 7: Check for Element Free Edges Use Verify to obtain the location of the element free edges a.Element: Verify/Element/Boundaries. b.Click Free Edges for Display Type. c.Click Apply. c a b

WS4-14 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 8: Specify Material Create isotropic material properties for chips and PCB a.Material: Create/Isotropic/Manual Input. b.Enter chip for Material Name. c.Click Input Properties.. d.Select Solid properties for Constitutive Model. e.Enter 2.24 for Thermal Conductivity. f.Click OK. g.Click Apply. c a b g f d e

WS4-15 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 8: Specify Material (Cont.) Create isotropic material properties a.Material: Create/Isotropic/Manual Input. b.Enter pcb for Material Name. c.Click Input Properties… d.Select Solid properties for Constitutive Model. e.Enter for Thermal Conductivity. f.Click OK. g.Click Apply. c a b g f d e

WS4-16 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 9: Define Element Properties Create the model element properties, assigning the material type to the correct region of the model. a.Properties: Create/ 3D/ Solid. b.Enter chip for Property Set Name. c.Select Standard Formulation for Option. d.Click Input Properties.. e.Click in the Material Name box and select chip under Material property Sets. f.Click OK. g.Enter Solid 2:4 for Select Members. h.Click Add. i.Click Apply. c a b i g h f d e

WS4-17 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 9: Define Element Properties (Cont.) a.Properties: Create/ 3D/ Solid b.Click pcb for Property Set Name. c.Select Standard Formulation. d.Click Input Properties… e.Click in the Material Name box and select pcb under Material Property Sets. f.Click OK. g.Enter Solid 1 for Select Members. h.Click Add. i.Click Apply. c a b i g h f d e

WS4-18 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 10: Define Temperature Dependent Field Define temperature dependent field a.Fields: Create/Material Property/Tabular Input. b.Enter conv_temp for Field Name. c.Select Temperature for Table Definition. d.Click Input Data.. e.See Figure for Data. f.Click OK. g.Click Apply. f c a b g d e

WS4-19 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 11: Create a Curve Use two nodes to create a curve a.Geometry: Create/Curve/Point. b.Select 2 Point for Option. c.Enter Node 938 for Starting Point List. d.Enter Node 1838 for Ending Point List. e.Click Apply. c a b d e

WS4-20 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 12: Create Curve at the Air Stream Copy Curve 1 to create a curve at the air stream. a.Geometry: Transform/Curve/Translate. b.Click Cartesian in Refer. CF for Type of Transformation. c.Enter for Translation Vector. d.Enter Curve 1 for Curve List. e.Click Apply. c a b d e

WS4-21 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 13: Mesh Curve 2 at the Airstream Mesh Curve 2 to create bar elements to represent the airstream. a.Elements: Create/Mesh/Curve. b.Select Bar2 for Topology. c.Enter Curve 2 for Curve List. d.Enter 0.25 for Value of Global Edge Length. e.Click Apply. c a b d e

WS4-22 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 14: Specify Material to Represent Air Specify the material properties of air a.Material: Create/Isotropic/Manual Input. b.Enter air for Material Name. c.Click Input Properties.. d.Enter Fluid properties for Constitutive Model. e.Enter 6.66e-4 for Thermal Conductivity. f.Enter for Specific Heat. g.Enter 5.01e-5 for Density. h.Enter 1.03e-3 for Dynamic Viscosity. i.Click OK. j.Click Apply. c a b j i g h f d e

WS4-23 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 15: Create Flow Tubes to Represent the Flowing Air Define flow tube (for flowing air) properties a.Properties: Create/1D/Flow Tube. b.Enter flow_tube for Property Set Name. c.Click Input Properties… d.Click in the Material Name box and select air under Material Property Sets. e.Enter 1.0 for Hydraulic Diam at Nod f.Click OK. g.Enter Curve 2 for Select Members. h.Click Add. i.Click Apply. c a b i g h f d e

WS4-24 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 16: Create Coupled Advection for Flowstream Use the Coupled Advection Feature to simulate the forced air convection on the back surface of PCB a.Loads/BCs: Create/Convection/Element Uniform. b.Enter flow_by_plate for New Set Name. c.Select 3D for Target Element Type. d.Select 1D for Region 2. e.Click Input Data.. f.Enter 8.33e-3 for Mass Flow Rate. g.Enter f:conv_temp for Temperature Function. h.Click OK. i.Click Select Application Region… j.Select Geometry for Geometry Filter. k.Select Solid 1.6 for Select Curves of Application Region. l.Click Add. m.Click Active List of Companion Region. n.Select Curve 2 for Select Curves of Companion Region. o.Click Add. p.Click OK. q.Click Apply. c a b j i g h f d e k l m n o p q

WS4-25 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 17: Apply Heat Flux Apply heat flux to free face of chips a.Loads/BCs: Create/ Applied Heat/ Element Uniform. b.Select Normal Fluxes for Option. c.Enter heat_flux for New Set Name. d.Select 3D for Target Element Type. e.Click Input Data… f.Enter 20 for Heat Flux. g.Click OK. h.Click Select Application Region… i.Select Geometry for Geometry Filter. j.Enter Solid for Select Solid Faces. k.Click Add. l.Click OK. m.Click Apply. c a b j i g h f d e k l m

WS4-26 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 18: Define the Inlet Temperature Define the inlet temperature of the fluid(air). a.Loads/BCs: Create/Temp (Thermal)/Noda. b.Enter inlet_temp for New Set Name. c.Click Input Data… d.Enter 20 for Boundary Temperature. e.Click OK. f.Click Select Application Region… g.Click Geometry for Geometry Filter. h.Enter Point 35 for Select Geometry Entities. i.Click Add. j.Click OK. c a b j i g h f d e k

WS4-27 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 19: Perform the Thermal Analysis Perform the analysis a.Analysis: Analyze/Entire Model/Full Run. b.Enter forced_conv_pcb for Job Name. c.Click Solution Type… d.Select Steady State analysis for Solution Type. e.Click Solution Parameters… f.Select Sorted for Data Deck Echo. g.Enter 100 for Default Init Temperature. h.Click OK. i.Click OK. j.Click Apply. c a b j i g h f d e

WS4-28 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 20: Attach the Results File Attach the XDB file a.Analysis: Attach XDB/ Result Entities/ Local. b.Click Select Results File… c.Select forced_conv_pcb.xdb for File name. d.Click OK. e.Click Apply. c a b d e

WS4-29 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 21: Display the Temperature Results Display the result a.Results: Create/ Quick Plot. b.Select SC1:DEFAULT, At Non- linear 100% for Select Result Cases. c.Click Temperature for Select Fringe Result. d.Click Apply. c a b d

WS4-30 NAS104, Workshop 4, March 2004 Copyright 2004 MSC.Software Corporation Step 22: Quit MSC.Patran Quit MSC.Patran a.Select File on the Menu Bar and select Quit from the drop down menu a