Create Gas Body

Allows you to define and simulate a gas body at a certain pressure within a confined space, particularly for applications like Insulated Glass Units (IGUs)

  1. In the Project Tree, open the Assembly workbench.
  2. In the Assembly workbench toolbar, select Create liquid or gas body > Gas.
  3. In the modeling window, carefully select the faces of your parts that define the boundaries of the gas volume.
    Note: Gas body can only be applied to faces.
    Important: For accurate simulation, the faces selected for a gas body should be from two different parts facing each other. This feature is primarily intended to simulate gas at a specific pressure in narrow gaps, such as those found in insulated glass units (IGUs).
  4. Optional: If desired, select the Add tangent faces checkbox. This will automatically select all faces tangent to your initially selected faces, which can be useful for quickly defining continuous gas boundaries.
  5. From the Pressure units drop down menu, specify units for the gas pressure.
  6. For Pressure, enter a value for the initial pressure of the gas.
  7. Click OK.
Key Considerations and Technical Details
  • Intended Use Case: The primary application for the gas body feature is to model the gas trapped between panes in insulated glass units. This requires the selected faces to be opposing surfaces from two distinct components that form a closed or nearly closed cavity.
  • Boyle's Law Adherence: Gas bodies created in SimSolid obey Boyle's Law. This fundamental gas law states that for a fixed amount of an ideal gas kept at a constant temperature, pressure and volume are inversely proportional.

    Mathematically this is expressed as:

    P 1 V 1 = P 2 V 2

    Where,

    P1and V1
    Initial pressure and volume
    P2 and V2
    Final pressure and volume
    • Implication: As the structural components enclosing the gas deform, the volume of the gas changes, and SimSolid automatically adjusts the pressure within the gas body according to Boyle's Law. This allows for the simulation of pressure-volume coupling effects.
  • Stiffness Contribution: Similar to liquid bodies, gas bodies contribute to the overall stiffness of the system. This stiffness arises from pressure exerted by the gas on the enclosing surfaces, which changes as the volume deforms.
  • Exclusion of Internal Components: If there are internal components within the gas volume that do not define its primary boundary or contribute to volume change, their faces should not be selected for the gas body. The gas body should represent the gas confined between the principal enclosing surfaces.

Comments

  1. Faces selected for the gas body should be from two different parts facing each other, as this feature is used to simulate gas at certain pressure in insulated glass units (IGUs).
  2. Gas bodies created in SimSolid obey Boyle’s law.