Creating the Physics Continuum for the Solid Components

Set up the continuum for the solid components.

The first physics continuum that you create is used to model all the solid components of the graphics card and the fan casings:
  1. Create a physics continuum.
  2. Rename the continuum to Solid Components.
  3. For the physics continuum, Continua > Solid Components, select the following models in order:
    Group Box Model
    Space Three Dimensional
    Time Steady
    Material Multi-Component Solid
    Multi-Component Solid Multi-Part Solid
    Optional Models Segregated Solid Energy
    Gradients (Selected automatically)
    Equation of State Constant Density
  4. Click Close.
  5. To review the models, open the Solid Components > Models node.


Multiple solid parts are modeled in the Solid Components continuum. Some parts are made of different materials. To define these materials in the multi-part solid model:
  1. Expand the Continua > Solid Components > Models > Multi-Part Solid node.
  2. Right-click the Solids node and choose Select Mixture Components....


  3. In the Select Mixture Components dialog, expand the Material Databases > Standard > Solids node.
  4. Select any four materials from the list.
    The materials that you choose here are not important — you will change the material properties for these selections in the subsequent steps.
  5. Click Apply and then Close.
  6. Rename the materials to ABS, Aluminum, Alumina, and Silicon.


  7. Edit the Multi-Part Solid node and set the material properties as follows:
    Node Property Setting
    ABS
    Material Properties
    Density > Constant Value 1050 kg/m^3
    Specific Heat > Constant Value 2050 J/kg-k
    Thermal Conductivity > Constant Value 2.5 W/m-K
    Node Property Setting
    Aluminum
    Material Properties
    Density > Constant Value 2700 kg/m^3
    Specific Heat > Constant Value 896 J/kg-k
    Thermal Conductivity > Constant Value 167 W/m-K
    Node Property Setting
    Alumina
    Material Properties
    Density > Constant Value 3960 kg/m^3
    Specific Heat > Constant Value 850 J/kg-k
    Thermal Conductivity > Constant Value 30 W/m-K
    Node Property Setting
    Silicon
    Material Properties
    Density > Constant Value 2330 kg/m^3
    Specific Heat > Constant Value 700 J/kg-k
    Thermal Conductivity > Constant Value 124 W/m-K
  8. Click Close.
The PCB is constructed from layers of FR-4 glass-reinforced laminate and copper foil. As a result, the PCB has the same thermal conductivity within the same layer but a different thermal conductivity between layers.

Add a material for the PCB to the mixture of solids:

  1. Right-click the Solids node and choose Select Mixture Components....
  2. In the Select Mixture Components dialog, expand the Material Databases > Standard > Solids node, and select any material from the list.
  3. Click Apply and then Close.
  4. Rename the new material to FR-4 + Copper.
  5. Expand the FR-4 + Copper > Material Properties node and set the material properties as follows:
    Node Property Setting
    FR-4 + Copper
    Material Properties
    Density > Constant Value 33 kg/m^3
    Specific Heat > Constant Value 37 J/kg-k
    Thermal Conductivity Method Orthotropic
To define the orthotropic thermal conductivity of the PCB:
  1. Expand the FR-4 + Copper > Material Properties > Thermal Conductivity > Orthotropic node and set the following properties:
    Node Property Setting
    k11 > Constant Value 10.0 W/m-k
    k22 > Constant Value 0.5 W/m-k
    k33 > Constant Value 10.0 W/m-k