The selected temperature set will be used to determine initial temperature
distribution.
MATERIAL
The selected temperature set will be used to determine temperature-dependent material
properties indicated on the MATTi Bulk Data Entries.
In addition, the SUBCASE ID of a Thermal Analysis
SUBCASE can be specified. The calculated temperature field is then
used to determine temperature-dependent material properties indicated on the
MATTi Bulk Data Entries.
This is only allowed for Linear Analysis. For Nonlinear Analysis,
TEMP(LOAD) will be used to update the temperature
dependent material.
LOAD
The selected temperature set will be used to determine an equivalent static load.
For Nonlinear Analysis, this temperature set will also be used to update the
temperature dependent material.
BOTH (Default)
Both MATERIAL and LOAD will use the same temperature
set.
SUBTYPE
<HTIME,TEMPT>
HTIME
Selects all the output time steps of a transient thermal subcase. This option is
supported for linear and Nonlinear Static Analysis.
TEMPT
Selects this option, where Grid-temperature is provided from either an external file
or an internal transient thermal subcase. This option is only supported for nonlinear
static or nonlinear transient subcases.
option
<SID>
No
default
SID
Set identification number of TEMP,
TEMPD, TEMPADD or TEMPT Bulk Data Entries. This
can also reference a Transient Heat Transfer subcase or a TSTRU Subcase Information Entry.
subtype_option
<ALL, Blank>
No
default
ALL
When SUBTYPE field is set to HTIME, the
subtype_option should be set to ALL.
Blank
When SUBTYPE field is set to TEMPT, then
subtype_option should be Blank.
Comments
The total load applied will be the sum of
external (LOAD command), thermal
(TEMP(LOAD/BOTH), or
DLOAD (via TLOAD#) command) and constrained displacement
(SPC command) loads.
Note:TEMPADD is supported for any
solution type/analysis where TEMP/TEMPD Bulk Data is
supported.
The comments below provide more detailed
information, while this table can provide a quick overview of the support for ways in which
temperature is included at the subcase level for different solution sequences.
TEMP(INIT)
TEMP(MAT)
TEMP(BOTH)
TEMP(LOAD)
TEMP(LOAD,HTIME)
(OSTTS)
TEMP(LOAD,TEMPT)
(OSTTS)
TEMP/TEMPD/TEMPADD Bulk via TLOAD# on DLOAD Subcase 1
Linear Static Analysis
Yes
Yes
Yes
Yes
Yes
No
NA
Linear Transient Analysis
Yes
Yes2
No
No
No
No
Yes2
Nonlinear Static Analysis
Yes
No
No
Yes
Yes
Yes
Yes
Nonlinear Transient Analysis
Yes
No
No
No
No
Yes
Yes
Explicit Dynamic Analysis
Yes
No
No
No
No
No
No
1 Typically, TEMP(INIT),
TEMP(MAT), TEMP(BOTH),
and TEMP(LOAD) refer to an ID of
TEMP/TEMPD/TEMPADD. While
DLOAD in the Subcase can reference TLOADi which
reference TEMP/TEMPD/TEMPADD in the
EXCITEID field and use TEMP or 3 in the
TYPE field.
2 If
TEMP(MAT) and
TEMP/TEMPD/TEMPADD via
TLOAD# are used for Linear Transient, then
TEMP(MAT) is used to identify temperature-dependent
material (MATT#).
The following table provides information on how
temperature loading and temperature-dependent material can be included in the model. This
table is a quick overview and more detailed information in the comments below:
Linear Static Analysis
Linear Transient Analysis
Nonlinear Static Analysis
Nonlinear Transient Analysis
Explicit Dynamic Analysis
Initial Temperature
TEMP(INIT) or TREF on
MATi
TEMP(INIT) or TREF on
MATi
TEMP(INIT) or TREF on
MATi
TEMP(INIT) or TREF on
MATi
TEMP(INIT) referencing Temperature field for
TABLEMD lookup for material update. 17
Temperature Loading
TEMP(LOAD), or
TEMP(BOTH)
TEMP/TEMPD/TEMPADD Bulk
Data via TLOAD# Bulk through DLOAD Subcase
Entry
TEMP(LOAD),TEMP/TEMPD/TEMPADD
Bulk Data via TLOAD# Bulk through DLOAD Subcase
Entry
TEMP/TEMPD/TEMPADD Bulk
Data via TLOAD# Bulk through DLOAD Subcase Entry.
TEMP(INIT),
TEMP(LOAD,TEMPT),
TEMP(LOAD,HTIME), or
DLOAD (via TLOAD# +
TEMP/TEMPD/TEMPADD
Bulk)
NA
In Linear Static Analysis,
TEMP(BOTH),
TEMP(LOAD), TEMP(MAT),
and TEMP(INIT) can be used before the subcase level or
inside the subcase. If used before the subcase level, it will apply to all subcases that do not
have their own corresponding command. Additionally, only the last instance of
TEMP(MAT) and
TEMP(INIT) will be used to update the corresponding
material or set the initial temperature for all subcases.
In Nonlinear Static Analysis
TEMP(LOAD) and
TEMP(INIT) can be used before the subcase level or inside
the subcase. If used before the subcase level, it will apply to all subcases that do not have
their corresponding command. Additionally, only the last instance of
TEMP(INIT) will be used to the set the initial temperature
or material properties (if TEMP(LOAD) is not present) for
all subcases.
Only one of
TEMP(MAT) or
TEMP(INIT) is allowed in any model.
TEMP(MAT), TEMP(LOAD),
and TEMP(BOTH) can point to a heat transfer subcase or
TEMP/TEMPD.
TEMP(INIT) cannot be used to reference a Heat Transfer
Subcase.
Static and thermal loads should have unique
set identification numbers.
In Linear Static Analysis, temperature strains
and material properties are calculated as: 3Figure 1.
Material properties are also calculated based on their corresponding
temperature-dependency (wherever applicable).
Where,
Thermal expansion coefficient.
The value of and temperature-dependent material properties can be defined
via the MATi or MATTi Bulk Data Entries depending on
whether temperature-dependent material are used. Temperature-dependent material are used if
TEMP(BOTH),
TEMP(MAT), or
TEMP(INIT) are specified in conjunction with
MATTi entries. If more than one or all three of
TEMP(BOTH/MAT/INIT)
are specified, then OptiStruct picks one of them for material
update based on the following priority.
TEMP(BOTH/MAT) have precedence over
TEMP(INIT). If both
TEMP(BOTH) and
TEMP(MAT) are present, then the last one is used for
material update.
If none of
TEMP(BOTH/MAT/INIT)
are specified, then the MATi material properties are used.
Load temperature defined by TEMP(LOAD) or
TEMP(BOTH).
If both TEMP(BOTH) and
TEMP(LOAD) are present, then OptiStruct picks the last one for the load temperature.
TEMP(BOTH) and
TEMP(LOAD) can be specified within the subcase in
multiple subcases. In such situations, the load temperature can vary for each subcase
depending on the entries specified within, and as mentioned previously, the last entry in
each subcase will determine the load temperature for that particular subcase.
Initial temperature defined by TEMP(INIT) or
TREF (TREF field on MATi).
TEMP(INIT) has precedence over
TREF. If TEMP(INIT) is not
specified, then TREF is used for the initial temperature.
SYSSETTING, TLOADMAT can
be used to activate TEMP(LOAD) for material update instead
of TEMP(MAT/INIT). It can also be used to
deactivate thermal loading in Structural Analysis.
In Nonlinear Static Analysis, temperature
strains and material properties are calculated as: 4
If
PARAM, THMLSTN, 0 (Default)Figure 2.
Or, if PARAM, THMLSTN, 1Figure 3.
Material properties are also calculated based on their corresponding
temperature-dependency (wherever applicable).
Where,
Thermal expansion coefficient.
The value of and temperature-dependent material properties can be defined
via the MATi or MATTi Bulk Data Entries depending on
whether temperature-dependent materials are used. Temperature-dependent materials are used
if TEMP(LOAD),
TEMP(INIT), or DLOAD(via
TLOAD# and TEMP/TEMPD/TEMPADD Bulk Data Entries) is
specified, in conjunction with MATTi entries. If
TEMP(LOAD) or DLOAD (via
TLOAD#) is not specified, then
TEMP(INIT) is used. If none of these are specified,
the MATi material properties are used.
Load temperature defined by TEMP(LOAD) or
DLOAD(via TLOAD# and
TEMP/TEMPD/TEMPADD Bulk Data Entries).
TEMP(LOAD) can be specified within the subcase in
multiple subcases. In such situations, the load temperature can vary for each subcase
depending on the entries specified within, and the last entry in each subcase will
determine the load temperature for that particular subcase.
Initial temperature defined by TEMP(INIT), or
TREF (TREF field on MATi).
TEMP(INIT) has precedence over
TREF.
TEMP(MAT),
TEMP(BOTH) cannot be used in Nonlinear Static Analysis
subcases. OptiStruct will error out, if they are specified inside
Nonlinear Static Analysis subcases. If TEMP(MAT) or
TEMP(BOTH) are specified outside Nonlinear Static
Subcases (either globally or in subcases of other solution sequences), then
TEMP(LOAD) should be defined inside the Nonlinear Static
Subcases in the model.
In Linear Transient Analysis, temperature strains are calculated as: 2Figure 4.
Material properties are also calculated based on their corresponding
temperature-dependency (wherever applicable).
Where,
Thermal expansion coefficient.
The value of and temperature-dependent material properties can be defined
via the MATi or MATTi Bulk Data Entries depending on
whether temperature-dependent material are used. Temperature-dependent material are used if
TEMP(MAT) or
TEMP(INIT) are specified in conjunction with
MATTi entries. If both TEMP(MAT)
and TEMP(INIT) are specified,
TEMP(MAT) has precedence over
TEMP(INIT).
If neither TEMP(MAT/INIT) are specified, then the
MATi material properties are used.
Temperature at time t defined via TEMP/TEMP/TEMPD Bulk Data Entries
via the TLOAD# Bulk Data Entry on a DLOAD Subcase
Information Entry.
Initial temperature defined by TEMP(INIT) or
TREF (TREF field on MATi).
TEMP(INIT) has precedence over
TREF.
If TEMP(INIT) is not specified, then
TREF is used for the initial temperature.
In Nonlinear Transient Analysis, temperature strains and material properties are
calculated as: 3
If PARAM, THMLSTN, 0 (Default)Figure 5.
Or if PARAM, THMLSTN, 1Figure 6.
Material properties are also calculated based on their corresponding
temperature-dependency (wherever applicable).
Where,
Thermal expansion coefficient. The value of and temperature-dependent material properties can be defined
via the MATi or MATTi Bulk Data Entries depending on
whether temperature-dependent materials are used. Temperature-dependent materials are used
if TEMP(LOAD),
TEMP(INIT), or DLOAD(via
TLOAD# and TEMP/TEMPD/TEMPADD Bulk Data Entries) is
specified, in conjunction with MATTi entries. If
TEMP(LOAD) or DLOAD (via
TLOAD#) is not specified, then
TEMP(INIT) is used. If none of these are specified,
the MATi material properties are used.
Load temperature defined by TEMP(LOAD) or
DLOAD (via TLOAD# and
TEMP/TEMPD/TEMPADD Bulk Data Entries).
TEMP(LOAD) can be specified within the subcase in
multiple subcases. In such situations, the load temperature can vary for each subcase
depending on the entries specified within, and the last entry in each subcase will
determine the load temperature for that particular subcase.
Initial temperature defined by TEMP(INIT),
TREF (TREF field on MATi), or
TEMPT Bulk Data Entry. TEMP(INIT)
has precedence over TREF and TEMPT. If
TEMP(INIT) is not specified:
In a model with subcase continuation, the initial temperature is determined by the
first subcase in the series. The determination follows the following rules.
For nonlinear transient subcases with
TEMP(LOAD,TEMPT), the temperature
field corresponding to HTINI defined in the TEMPT
Bulk data Entry is used as the initial temperature field.
If TEMPT format is not used, then TREF is used
for the initial temperature.
Otherwise, TREF is used for the initial temperature.
TEMP(MAT), TEMP(BOTH), and
TEMP(LOAD) cannot be used in Nonlinear Transient Analysis subcases.
OptiStruct will error out, if they are specified inside Nonlinear
Transient Analysis subcases. If TEMP(MAT), TEMP(LOAD),
or TEMP(BOTH) are specified outside Nonlinear Transient Subcases (either
globally or in subcases of other solution sequences), then DLOAD (via
TLOAD# and
TEMP/TEMPD/TEMPADD Bulk Data
Entries) should be defined inside the Nonlinear Transient Subcases in the model.
In versions prior to OptiStruct 8.0, thermal loads were selected in the Subcase Information
section using the LOAD data selector. In version
8.0, the TEMPERATURE data selector was added to perform this function. It is
possible to revert to the old behavior mode by setting the LOADTEMP option to
SHAREID in the Configuration File.
For Linear Static Subcase,
TEMP(LOAD),
TEMP(BOTH), or
TEMP(MAT) can point to a heat transfer subcase or
TSTRU ID. The temperature field from a steady-state heat transfer analysis
or at the final time step of a transient heat transfer analysis will be used. When
TEMP(LOAD) or
TEMP(BOTH) points to a transient heat transfer subcase or
TSTRU ID, TIME= ALL can be used to select
temperature fields at all time steps for coupled Thermal Structural Analysis.
HTIME= ALL cannot be defined in
TEMP(INIT) or TEMP(MAT) entry. For more
information, refer to One Step Transient Thermal Stress Analysis.
For Nonlinear Static Subcase,
TEMP(LOAD) can point to heat transfer subcase. The
temperature field from a steady-state heat transfer analysis will be used to update thermal
loading and temperature-dependent material properties. If
TEMP(LOAD) points to transient thermal subcase from
Nonlinear Static Subcase, then HTIME= ALL can be used to select
temperature fields at all time steps for coupled Thermal Structural Analysis.
HTIME=ALL cannot be defined in
the TEMP(INIT) entry. For more information, refer to One Step Transient Thermal Stress Analysis.
For Nonlinear One Step Transient Thermal
Stress Analysis, a more flexible definition on thermal load can be used by the combination of
TEMP(LOAD) and flag TEMPT. In this
format, the thermal load can be read from either an external file (HFILE)
or an internal Transient Thermal Analysis (HSUB). In this case, grid
temperature values at different time steps are predefined and mapped to the current Nonlinear
Structural Analysis. The mapping rule is defined in TEMPT card. The
referenced TEMPT card ID is defined in SUBTYPE.
TEMPT via the TEMP Subcase Information Entry can be
specified for both nonlinear static and nonlinear transient subcases.
In Nonlinear Analysis, the thermal expansion
coefficient is a secant value. You can obtain its value from the instantaneous
thermal expansion coefficient using:Figure 7.
Where,
Initial temperature.
Instantaneous thermal expansion coefficient.
Secant thermal expansion coefficient at temperature . This is used by OptiStruct.
When PARAM,THMLSTN,1 is specified, the secant thermal expansion
coefficient can be obtained by:Figure 8.
Where, is the reference temperature defined on the material
entry.
For the initial state, the secant thermal expansion coefficient, .
If an initial temperature (predefined outside of the subcases)
is different from the temperature at the very beginning of a subcase and the resulting thermal
expansion is nonzero, the thermal strain due to this temperature difference is counted.
For Explicit Dynamic Analysis (NLEXPL),
TEMP(INIT) is supported to identify temperature field for
looking up the initial material data via the TABLEMD entry referenced on the
corresponding MATS1 entry.