김경종
360 lines
19 KiB
Markdown
360 lines
19 KiB
Markdown
<!-- source-page: 161 -->
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The \*FILM PROPERTY option must appear in the model definition portion of the input file.
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Abaqus/CAE Usage: Interaction module:
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Create Interaction Property: Name: film property table name and Film condition
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Create Interaction: Surface film condition or Concentrated film condition: select region: Definition: Property Reference and Film interaction property: film property table name
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# Modifying or removing film conditions
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Film conditions can be added, modified, or removed as described in “Applying loads: overview,” Section 34.4.1.
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# Specifying time-dependent film conditions
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For a uniform film both the sink temperature and the film coefficient can be varied with time by referring to amplitude definitions. One amplitude curve defines the variation of the sink temperature, , with time. Another amplitude curve defines the variation of the film coefficient, h, with time. See “Prescribed conditions: overview,” Section 34.1.1, and “Amplitude curves,” Section 34.1.2, for more information.
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Input File Usage: Use the following options to define time-dependent film conditions:
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```txt
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*AMPLITUDE, NAME=temp_amp
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*AMPLITUDE, NAME=h_amp
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*FILM, AMPLITUDE=temp_amp, FILM AMPLITUDE=h_amp
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*SFILM, AMPLITUDE=temp_amp, FILM AMPLITUDE=h_amp
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*CFILM, AMPLITUDE=temp_amp, FILM AMPLITUDE=h_amp
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```
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Abaqus/CAE Usage: Use the following input to define time-dependent film conditions. If you select an analytical field to define the interaction, the analytical field affects only the film coefficient.
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```txt
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Interaction module:
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Create Amplitude: Name: h_amp
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Create Amplitude: Name: temp_amp
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Create Interaction: Surface film condition or Concentrated film condition: select region: Definition: Embedded Coefficient or select an analytical field: Film coefficient amplitude: h_amp and Sink amplitude: temp_amp
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```
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# Examples
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A uniform, time-dependent film condition can be defined for face 2 of element 3 by
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```txt
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*AMPLITUDE, NAME=sink
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0.0, 0.5, 1.0, 0.9
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*AMPLITUDE, NAME=famp
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```
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<!-- source-page: 162 -->
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```txt
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0.0, 1.0, 1.0, 22.0
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...
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*STEP
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** For an Abaqus/Standard analysis:
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*HEAT TRANSFER
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** For an Abaqus/Explicit analysis:
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*DYNAMIC TEMPERATURE-DISPLACEMENT, EXPLICIT
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...
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*FILM, AMPLITITUDE=sink, FILM AMPLITITUDE=famp
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3, F2, 90.0, 2.0
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```
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A uniform, temperature-dependent film coefficient and a time-dependent sink temperature can be defined for face 2 of element 3 by
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```txt
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*AMPLITUDE, NAME=sink
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0.0, 0.5, 1.0, 0.9
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*FILM PROPERTY, NAME=filmp
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2.0, 80.0
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2.3, 90.0
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8.5, 180.0
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...
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*STEP
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** For an Abaqus/Standard analysis:
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*HEAT TRANSFER
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** For an Abaqus/Explicit analysis:
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*DYNAMIC TEMPERATURE-DISPLACEMENT, EXPLICIT
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...
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*FILM, AMPLITUDE=sink
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3, F2, 90.0, filmp
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```
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A uniform, temperature-dependent film coefficient and a time-dependent sink temperature can be defined for node 2, where the nodal area is 50, by
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```txt
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*AMPLITUDE, NAME=sink
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0.0, 0.5, 1.0, 0.9
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*FILM PROPERTY, NAME=filmp
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2.0, 80.0
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2.3, 90.0
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8.5, 180.0
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...
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*STEP
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** For an Abaqus/Standard analysis:
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*HEAT TRANSFER
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** For an Abaqus/Explicit analysis:
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```
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<!-- source-page: 163 -->
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```txt
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*DYNAMIC TEMPERATURE-DISPLACEMENT, EXPLICIT
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...
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*CFILM, AMPLITUDE=sink,
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2, 50, 90.0, filmp
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```
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# Defining nonuniform film conditions in a user subroutine
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In Abaqus/Standard a nonuniform film coefficient can be defined as a function of position, time, temperature, etc. in user subroutine FILM for element-based, surface-based, as well as node-based film conditions. Amplitude references are ignored if a nonuniform film is prescribed.
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<table><tr><td>Input File Usage:</td><td>Use the following option to define a nonuniform film coefficient for an element-based film condition:*FILMelement number or element set name, FnNUUse the following option to define a nonuniform film coefficient for a surface-based film condition:*SFILMsurface name, FNUUse the following option to define a nonuniform film coefficient for a node-based film condition:*CFILM, USERnode number or node set name, nodal area</td></tr><tr><td>Abaqus/CAE Usage:</td><td>Element-based film conditions to define a nonuniform film coefficient are not supported in Abaqus/CAE. However, similar functionality is available using surface-based film conditions. Use the following option to define a nonuniform film coefficient for a surface-based film condition:Interaction module: Create Interaction: Surface film condition:select region: Definition: User-definedUse the following option to define a nonuniform film coefficient for a node-based film condition:Interaction module: Create Interaction: Concentrated film condition:select region: Definition: User-defined</td></tr></table>
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# Prescribing boundary radiation
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Heat flux on a surface due to radiation to the environment is governed by
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$$
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q = \sigma \epsilon \big [ (\theta - \theta^ {Z}) ^ {4} - (\theta^ {0} - \theta^ {Z}) ^ {4} \big ],
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$$
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where
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q is the heat flux across the surface,
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<!-- source-page: 164 -->
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$\epsilon$ is the emissivity of the surface, $\sigma$ is the Stefan-Boltzmann constant, $\theta$ is the temperature at this point on the surface, $\theta^0$ is an ambient temperature value, and $\theta^Z$ is the value of absolute zero on the temperature scale being used.
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Heat flux due to radiation can be defined on element faces, on surfaces, or at nodes.
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# Specifying element-based radiation
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To specify element-based radiation within a heat transfer or coupled temperature-displacement step definition, you must provide the ambient temperature value, $\theta ^ { 0 }$ , and the emissivity of the surface, . The radiation is applied to element edges in two dimensions and to element faces in three dimensions. The edge or face of the element upon which the radiation occurs is identified by a radiation type label depending on the element type (see Part VI, “Elements”).
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Input File Usage: \*RADIATE element number or element set name, $ { \mathrm { R } n } , { \theta ^ { 0 } } , \epsilon$
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Abaqus/CAE Usage: Interaction module: Create Interaction: Surface radiation: select region: Radiation type: To ambient, Emissivity distribution: select an analytical field, Emissivity: , and Ambient temperature: $\theta ^ { 0 }$
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# Specifying surface-based radiation to ambient
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You can apply the radiation to a surface rather than to individual element faces. The surface that contains the element and face information is defined as described in “Element-based surface definition,” Section 2.3.2. You must specify the surface name; the radiation load type label, R (or RPOS, RNEG in the case of shells); the ambient temperature value, $\theta ^ { 0 } { } _ { ; }$ ; and the emissivity of the surface, .
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Input File Usage: \*SRADIATE surface name, $\mathrm { R } , \theta ^ { 0 } , \epsilon$
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Abaqus/CAE Usage: Interaction module: Create Interaction: Surface radiation: select region: Radiation type: To ambient, Emissivity distribution: Uniform, Emissivity: , and Ambient temperature: $\theta ^ { 0 }$
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# Specifying node-based radiation to ambient
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To specify node-based radiation within a heat transfer or coupled temperature-displacement step definition, you must provide the nodal area for a specified node number or node set; the ambient temperature value, $\theta ^ { 0 } { ; }$ ; and the emissivity of the surface, . The associated degree of freedom is 11. For shell elements where the concentrated radiation is associated with a degree of freedom other than 11, you can specify the required data for a duplicate node that is constrained to the appropriate degree of freedom of the shell node by using an equation constraint.
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Input File Usage: \*CRADIATE node number or node set name, nodal area, $\theta ^ { 0 }$ ,
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<!-- source-page: 165 -->
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Abaqus/CAE Usage: Interaction module: Create Interaction: Concentrated radiation to ambient: select region: Associated nodal area: Emissivity: and Ambient temperature: $\theta ^ { 0 }$
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# Specifying time-dependent radiation
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The user-specified value of the ambient temperature, $\theta ^ { 0 }$ , can be varied throughout the step by referring to an amplitude definition. See “Applying loads: overview,” Section 34.4.1, and “Amplitude curves,” Section 34.1.2, for details.
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# Specifying average-temperature radiation conditions
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The average-temperature radiation condition is an approximation to the cavity radiation problem, where the radiative flux per unit area into a facet is
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$$
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q _ {i} ^ {c} = \sigma \epsilon_ {i} \left(\theta_ {A V G} ^ {4} - (\theta_ {i} - \theta^ {Z}) ^ {4}\right),
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$$
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with the average temperature for the surface $\theta _ { A V G }$ being calculated as
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$$
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\theta_ {A V G} ^ {4} = \frac {1}{A _ {t o t a l}} \sum_ {j = 1} ^ {N} A _ {j} (\theta_ {j} - \theta^ {Z}) ^ {4}.
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$$
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The average temperature in the cavity is computed at the beginning of each increment and held constant over the increment. Therefore, the average-temperature radiation condition has some dependency on the increment size, and you need to ensure that the increment size you use is appropriate for your model. If you see large changes in temperature over an increment, you may need to reduce the increment size.
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Input File Usage: Use the following option to define the average-temperature radiation condition on a surface:
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\*SRADIATE
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surface name, AVG, ,
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Abaqus/CAE Usage: Interaction module: Create Interaction: Surface radiation: select the surface region: Radiation type: Cavity approximation (3D only), Emissivity:
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# Specifying the value of absolute zero
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You can specify the value of absolute zero, $\theta ^ { Z }$ , on the temperature scale being used; you must specify this value as model data. By default, the value of absolute zero is 0.0.
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Input File Usage: \*PHYSICAL CONSTANTS, ABSOLUTE ZERO=
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Abaqus/CAE Usage: Any module: Model→Edit Attributes→model\_name: Absolute zero temperature: $\theta ^ { Z }$
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<!-- source-page: 166 -->
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# Specifying the value of the Stefan-Boltzmann constant
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If boundary radiation is prescribed, you must specify the Stefan-Boltzmann constant, ; this value must be specified as model data.
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Input File Usage: \*PHYSICAL CONSTANTS, STEFAN BOLTZMANN=
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Abaqus/CAE Usage: Any module: Model→Edit Attributes→model\_name:
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Stefan-Boltzmann constant:
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# Modifying or removing boundary radiation
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Boundary radiation conditions can be added, modified, or removed as described in “Applying loads: overview,” Section 34.4.1.
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<!-- source-page: 167 -->
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# 34.4.5 ELECTROMAGNETIC LOADS
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Products: Abaqus/Standard Abaqus/CAE
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# References
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• “Prescribed conditions: overview,” Section 34.1.1
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• “Applying loads: overview,” Section 34.4.1
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• \*CECHARGE
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• \*CECURRENT
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• \*DECHARGE
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• \*DECURRENT
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• \*DSECHARGE
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• \*DSECURRENT
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• “Defining a concentrated current,” Section 16.9.25 of the Abaqus/CAE User’s Guide, in the HTML version of this guide
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• “Defining a surface current,” Section 16.9.26 of the Abaqus/CAE User’s Guide, in the HTML version of this guide
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• “Defining a body current,” Section 16.9.27 of the Abaqus/CAE User’s Guide, in the HTML version of this guide
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• “Defining a surface current density,” Section 16.9.28 of the Abaqus/CAE User’s Guide, in the HTML version of this guide
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• “Defining a body current density,” Section 16.9.29 of the Abaqus/CAE User’s Guide, in the HTML version of this guide
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• “Defining a concentrated charge,” Section 16.9.30 of the Abaqus/CAE User’s Guide, in the HTML version of this guide
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• “Defining a surface charge,” Section 16.9.31 of the Abaqus/CAE User’s Guide, in the HTML version of this guide
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• “Defining a body charge,” Section 16.9.32 of the Abaqus/CAE User’s Guide, in the HTML version of this guide
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# Overview
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As outlined in “Prescribed conditions: overview,” Section 34.1.1, electromagnetic loads can be applied in “Piezoelectric analysis,” Section 6.7.2; “Coupled thermal-electrical analysis,” Section 6.7.3; “Fully coupled thermal-electrical-structural analysis,” Section 6.7.4; “Eddy current analysis,” Section 6.7.5; and “Magnetostatic analysis,” Section 6.7.6.
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<!-- source-page: 168 -->
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The types of electromagnetic loads available depend on the analysis being performed, as described in the sections below. See “Applying loads: overview,” Section 34.4.1, for general information that applies to all types of loading.
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# Defining time-dependent electromagnetic loads
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The prescribed magnitude of a concentrated or a distributed electromagnetic load can vary with time during a step according to an amplitude definition, as described in “Prescribed conditions: overview,” Section 34.1.1. If different variations are needed for different loads, each load can refer to its own amplitude definition.
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In a time-harmonic eddy current analysis all loads are assumed to be time-harmonic.
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# Modifying electromagnetic loads
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Concentrated or distributed electromagnetic loads can be added, modified, or removed as described in “Applying loads: overview,” Section 34.4.1.
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# Prescribing electromagnetic loads for piezoelectric analyses
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In a piezoelectric analysis a concentrated electric charge can be prescribed at nodes, a distributed electric surface charge can be defined on element faces and surfaces, and a distributed electric body charge can be defined on elements.
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# Specifying concentrated electric charge
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To specify a concentrated electric charge, specify the node or node set and the magnitude of the charge.
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Input File Usage: \*CECHARGE
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node number or node set name, , charge magnitude
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Abaqus/CAE Usage: Load module: Create Load: choose Electrical/Magnetic for the
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Category and Concentrated charge for the Types for Selected
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Step; Magnitude: charge magnitude
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# Specifying element-based distributed electric charge
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You can specify a distributed surface charge (on element faces) or a distributed body charge (charge per unit volume). For an element-based surface charge you must identify the face of the element upon which the charge is prescribed in the charge label. The distributed charge types available depend on the element type. Part VI, “Elements,” lists the distributed charges that are available for particular elements.
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Input File Usage: \*DECHARGE
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element number or element set name, charge label, charge magnitude
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where charge label is ESn or EBF
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<!-- source-page: 169 -->
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Abaqus/CAE Usage: Use the following input to define a distributed surface charge on element faces:
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Load module: Create Load: choose Electrical/Magnetic for the Category and Surface charge for the Types for Selected Step; Distribution: select an analytical field, Magnitude: charge magnitude
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Use the following input to define a body charge:
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Load module: Create Load: choose Electrical/Magnetic for the Category and Body charge for the Types for Selected Step
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# Specifying surface-based distributed electric charge
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When you specify a distributed electric charge on a surface, the element-based surface (see “Elementbased surface definition,” Section 2.3.2) contains the element and face information. You must specify the surface name, the electric charge label, and the electric charge magnitude.
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Input File Usage: \*DSECHARGE surface name, ES, charge magnitude
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Abaqus/CAE Usage: Load module: Create Load: choose Electrical/Magnetic for the Category and Surface charge for the Types for Selected Step; Distribution: Uniform, Magnitude: charge magnitude
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# Specifying electric charge in direct-solution steady-state dynamics analysis
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In the direct-solution steady-state dynamics procedure, electric charges are given in terms of their real and imaginary components.
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Input File Usage: Use the following options to define electric charges in direct-integration steadystate dynamics analysis:
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\*CECHARGE, REAL or IMAGINARY (real or imaginary component)
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\*DECHARGE, REAL or IMAGINARY
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\*DSECHARGE, REAL or IMAGINARY
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Abaqus/CAE Usage: Load module: Create Load: choose Electrical/Magnetic for the Category and Concentrated charge, Surface charge, or Body charge for the Types for Selected Step; Magnitude: real component + imaginary component
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# Loading in mode-based and subspace-based procedures
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Electrical charge loads should be used only in conjunction with residual modes in the eigenvalue extraction step, due to the “massless” mode effect. Since the electrical potential degrees of freedom do not have any associated mass, these degrees of freedom are essentially eliminated (similar to Guyan reduction or mass condensation) during the eigenvalue extraction. The residual modes represent the static response corresponding to the electrical charge loads, which will adequately represent the potential degree of freedom in the eigenspace.
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<!-- source-page: 170 -->
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# Prescribing electromagnetic loads for coupled thermal-electrical and fully coupled thermal-electrical-structural analyses
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In a coupled thermal-electrical analysis and fully coupled thermal-electrical-structural analysis a concentrated current can be prescribed at nodes, distributed current densities can be defined on element faces and surfaces, and distributed body currents can be defined on elements.
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# Specifying concentrated current density
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To define concentrated currents, specify the node or node set and the magnitude of the current.
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Input File Usage: \*CECURRENT
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node number or node set name, , current magnitude
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Abaqus/CAE Usage: Load module: Create Load: choose Electrical/Magnetic for the
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Category and Concentrated current for the Types for Selected
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Step; Magnitude: current magnitude
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# Specifying element-based distributed current density
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You can specify distributed surface current densities (on element faces) or distributed body current densities (current per unit volume). For element-based surface current densities you must identify the face of the element upon which the current is prescribed in the current label. The distributed current types available depend on the element type. Part VI, “Elements,” lists the distributed current densities that are available for particular elements.
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Input File Usage: \*DECURRENT
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element number or element set name, current density label, current density magnitude
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where current density label is CSn, CS1, CS2, or CBF
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Abaqus/CAE Usage: Use the following input to define a distributed surface current density on element faces:
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Load module: Create Load: choose Electrical/Magnetic for the Category and Surface current for the Types for Selected Step; Distribution:
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select an analytical field, Magnitude: current density magnitude
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Use the following input to define a body current density:
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Load module: Create Load: choose Electrical/Magnetic for the Category and Body current for the Types for Selected Step
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# Specifying surface-based distributed current densities
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When you specify distributed current densities on a surface, the element-based surface (see “Elementbased surface definition,” Section 2.3.2) contains the element and face information. You must specify the surface name, the current density label, and the current density magnitude.
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