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Thermal load (Load)

Last modified by Iwona Budny Bjergø on 2022/01/18 12:23

Depending on the current FEM-Design module, uniform or non-uniform temperature variation can be added to the structural elements as loads.

FEM-Design ModuleTemperature VariationLoad Command
1582555877428-975.pngNon-uniform temperature in Beams1583337972551-581.png  Line temperature variation
Non-uniform temperature in Plates1583337991589-319.png  Surface temperature variation
1582555973562-928.png 1582557800048-361.pngUniform temperature in Walls1583337991589-319.png  Surface temperature variation
1582554329138-224.pngUniform/Non-uniform temperature in bar elements1583337972551-581.png  Line temperature variation
Uniform/Non-uniform temperature in planar elements1583337991589-319.png  Surface temperature variation
1582554910943-252.pngUniform/Non-uniform temperature in bar elements1583337981481-967.png  Line temperature variation

Table: Temperature load types by FEM-Design modules

Line Temperature variation

PropertyValue
Default Short CommandLTL
Icon1583337981481-967.png
  • Non-Uniform Temperature Variation in Beams
    In 1583338105555-226.png  Plate module, non-uniform temperature variation can be defined along beam action line or a part of it. The absolute value of the temperature has to be the same in the top and bottom cords:

    |dttop| = |dtbottom|

    So the meaning of the temperature variation is the following:

    |dt| = ±|dttop-dtbottom| = ±2 x |dttop|

    1583396976365-679.png

    The temperature variation can be linearly variable along the action line, so it can be different in the start and end point of the action line.

  • Uniform/Non-Uniform Temperature Variation in Bar Elements
    In 1583396996282-480.png  3D Structure and 1583397004039-964.png  3D Frame modules, uniform or non-uniform temperature variation can be defined along beam and column action lines or a part of them. The temperature values can be different in the top (t) and bottom (t’) cords.
    1583397030869-913.png
    The temperature variation can be linearly variable along the action line, so it can be different in the start and end point of the action line.

Depending on the current FEM-Design module, temperature load can be easily added to bar elements. The load properties and definition tools are available on the tool palette of the 1583397118461-766.png  Line temperature variation load.

1583397129399-145.png

Figure: Tool palettes of Line temperature variation load

Definition steps

  1. Select the load case from the load case drop-down list from 1583397143775-819.png  tabmenu, which you would like to add the new load(s) to.
    If you have not defined a load case yet, you can also define and set at the  Default settings by giving a load case name.
    The load will be displayed on the layer assigned to the selected load case and in the layer’s color.
  2. Set the temperature values at the start and end point of the “load” action line to the current temperature unit (that can be set at Settings > Units) in the tool palette or at 1583397189418-748.png  Default settings. If you inactivate the arrow ( 1583397179342-461.png  ) next to the temperature fields, you can type different temperature values in the “1” and “2” fields.
    1583397198960-763.png
    Figure: Settings dialogs (the meaning of the “t” values)
  3. Define the direction of the plane you would like to place the thermal load (only in 3D modules).
  4. Add the thermal to its belonging bar element by selecting it with 1583398392694-683.png .
    Or, choose a method for the action line definition (geometry) and define the thermal load. Use this method, if you would like to place the load on a part of the bar element.

    With the special tool called Object’s local system (1583398415317-771.png , only in 3D modules) you can set the load’s plane direction directly to a selected axis of the bar element’s local system in the tool palette and by the clicking on the bar element. So, with this tool, you can merge 3rd and 4th steps to one step, if the direction of the thermal load plane is equal to a required axis direction of the assigned bar element’s local system.

    1583398439125-131.png
    Figure: Different ways of thermal load definition

Optional steps:

  1. Modify the load properties (the host load case and temperature values with the 1583398485294-999.png  Properties tool of the Line temperature variation load tool palette.
  2. Modify the direction of the thermal load plane with the editing tools (Editing Loads).
  3. Set the display settings of the thermal load (Load Display Settings).

Surface Temperature variation

PropertyValue
Default Short CommandLTS
Icon1583337991589-319.png
  • Non-Uniform Temperature Variation in Plates
    In 1583398554689-506.png  Plate module, non-uniform temperature variation can be defined in plate region or a part of it. The absolute value of the temperature has to be the same in the top and bottom cords:

    |dttop| = |dtbottom|

    So the meaning of the temperature variation is the following:

    |dt| = ±|dttop-dtbottom| = ±2 x |dttop|

    The temperature variation can be linearly variable along the action plane. Temperature value in 3 region points defines the linearly variable temperature in a plate object.
  • Uniform Temperature Variation in Walls
    In 1583403731784-962.png  Wall module and 1583403739222-253.png  Plane Strain modules, uniform temperature load can be defined in wall region or a part of it:

    tsi= ttop = tbottom

    1583403750167-625.png

    The temperature variation can be linearly variable along the action plane. Temperature value in 3 region points defines the linearly variable temperature in a wall object.
  • Uniform/Non-Uniform Temperature Variation in Planar Elements
    In 1583403843740-281.png  3D Structure module, uniform or non-uniform temperature variation can be defined in plate, wall and shell regions or a part of them. The temperature values can be different in the top (t’) and bottom (t) cords.

    1583403872316-426.png
    The temperature variation can be linearly variable along the action plane. Temperature value in 3 region points defines the linearly variable temperature in a plate, wall or shell object.

Depending on the current FEM-Design module, temperature load can be easily added to planar objects. The load properties and definition tools are available on the tool palette of the 1583403901437-184.png  Surface support motion load.

1583403895376-878.png

Figure: Tool palettes of Surface temperature variation load

Definition steps

  1. Select the load case from the load case drop-down list from Loads tabmenu, which you would like to add the new load(s) to.
    If you have not defined a load case yet, you can also define and set at the 1583403915616-172.png  Default settings by giving a load case name.
    The load will be displayed on the layer assigned to the selected load case and in the layer’s color.
  2. First, define temperature variation constant along the load action plane. Set the motion value in the “t1” fields according to the current temperature unit (that can be set at Settings > Units) in the tool palette or at 1583403947241-964.png  Default settings.
    1582804849244-917.pngThe local z’ axis of the surface element (plate, wall) points to the “top” surface temperature (t’) in 1583403984698-364.png  3D Structure module.

    1583403994426-214.png

    Figure: Settings dialogs (the meaning of the “t” values)

  3. Add the thermal load to its belonging surface element by selecting it with 1583404022531-868.png .
    Or, choose a method for the action surface definition (geometry) and define the surface thermal load. Use this method, if you would like to place the load on a part of the surface element. In this case set the working plane into the element’s plane.

1583404044306-283.png

Figure: Different ways of surface thermal load definition

Optional steps:

  1. Use the 1583404079914-439.png  Variable intensity tool, if you would like to define variable surface thermal load. Set the new temperature values (dt1/t1/ts1, dt2/t2/ts2 and dt3/t3/ts3). If you inactivate the arrows ( 1583404094594-519.png  ) next to the value fields, you can type different values by the t fields. Select the constant surface temperature load that you would like to modify being variable. Give the position of the three temperature values. You may click outside the surface load’s action plane too.
  2. Place a hole/opening in a surface thermal load. Use the 1583404109017-194.png  Hole tool of the Surface temperature variation load.
  3. Modify the load properties (the host load case and temperature values with the image-20200305085457-35.png  Properties tool of the Surface support motion load tool palette.
  4. Set the display settings of the thermal load (Load Display Settings).