TEMPG

Subcase Information Entry Selects the temperature set to be used in either material property calculations or thermal loading.

Format

TEMPG (type, SUBTYPE=subtype_option) = option

Examples

TEMPG(LOAD)=15
TEMPG(MATERIAL)=7
TEMPG(INITIAL)=7
TEMPG(LOAD,HTIME=ALL)=8
TEMPG(LOAD,TEMPT)=23

Definitions


Argument	Options	Description
`type`	<INITIAL, MATERIAL, LOAD> No default	INITIAL The selected temperature is 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.
`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, TEMPSEC, TEMPT and TEMPSEC 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 is the sum of external (LOAD command), thermal (TEMP(LOAD), or DLOAD (via TLOAD#) command) and constrained displacement (SPC command) loads.
Note: TEMPADD is supported for any solution type/analysis where TEMP/TEMPD/TEMPSEC 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.


	TEMPG(INIT)	TEMPG(MAT)	TEMPG(LOAD)	TEMPG(LOAD,HTIME) (OSTTS)	TEMPG(LOAD,TEMPT) (OSTTS)	TEMP/TEMPD/TEMPADD/TEMPSEC Bulk via TLOAD# on DLOAD Subcase ¹
Linear Static Analysis	Yes	Yes	Yes	Yes	No	NA
Linear Transient Analysis	Yes	Yes²	No	No	No	Yes²
Nonlinear Static Analysis	Yes	No	Yes	Yes	Yes	Yes
Nonlinear Transient Analysis	Yes	No	No	No	Yes	Yes

¹ Typically, TEMPG(INIT), TEMPG(MAT), and TEMPG(LOAD) refer to an ID of TEMP/TEMPD/TEMPADD/TEMPSEC. While DLOAD in the Subcase can reference TLOADi which reference TEMP/TEMPD/TEMPADD/TEMPSEC in the EXCITEID field and use TEMP or 3 in the TYPE field.

² If TEMPG(MAT) and TEMP/TEMPD/TEMPADD/TEMPSEC via TLOAD# are used for Linear Transient, then TEMPG(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
Initial Temperature	TEMPG(INIT) or `TREF` on MATi	TEMPG(INIT) or `TREF` on MATi	TEMPG(INIT) or `TREF` on MATi	TEMPG(INIT) or `TREF` on MATi
Temperature Loading	TEMPG(LOAD)	TEMP/TEMPD/TEMPADD Bulk Data via TLOAD# Bulk through DLOAD Subcase Entry	TEMPG(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.
Temperature Loading for NL Subcase in OSTTS	NA	NA	TEMPG(LOAD,HTIME) or TEMPG(LOAD,TEMPT)	TEMPG(LOAD,TEMPT)
Initial Temperature for NL Subcase in OSTTS	NA	NA	`TREF`, TEMPG(INIT)	`TREF` or TEMPG(INIT)
Temperature-dependent material	TEMPG(INIT) or TEMPG(MAT	TEMPG(INIT) or TEMPG(MAT)	TEMPG(INIT), TEMPG(LOAD), TEMPG(LOAD,TEMPT), TEMPG(LOAD,HTIME) or DLOAD (via TLOAD# + TEMP/TEMPD/TEMPADD Bulk)	TEMPG(INIT), TEMPG(LOAD,TEMPT), TEMPG(LOAD,HTIME), or DLOAD (via TLOAD# + TEMP/TEMPD/TEMPADD Bulk)

In Linear Static Analysis, TEMPG(LOAD), TEMPG(MAT), and TEMPG(INIT) can be used before the subcase level or inside the subcase. If used before the subcase level, it applies to all subcases that do not have their own corresponding command.
In Nonlinear Static Analysis TEMPG(LOAD) and TEMPG(INIT) can be used before the subcase level or inside the subcase. If used before the subcase level, it applies to all subcases that do not have their corresponding command.
Each subcase can have its own initial temperature or material temperature by defining TEMPG(INIT) or TEMPG(MAT) in the subcase section. If TEMPG(INIT) or TEMPG(MAT) is defined before the subcase level, these definitions apply to all subcase that do not have their corresponding command. TEMPG(MAT) and TEMPG(LOAD) can point to a heat transfer subcase or TEMP/TEMPD. TEMPG(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 (see 2):
$ε_{T} = A (T_{M a t}) (T_{F i n a l} - T_{I n i t i a l})$ $ε_{T} = A (T_{M a t}) (T_{F i n a l} - T_{I n i t i a l})$
Material properties are also calculated based on their corresponding temperature-dependency (wherever applicable).
Where,

$A (T_{M a t})$ $A (T_{M a t})$

Thermal expansion coefficient.

The value of $A (T_{M a t})$ $A (T_{M a t})$ 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 TEMPG(MAT), or TEMPG(INIT) are specified in conjunction with MATTi entries.

TEMPG(MAT) has precedence over TEMPG(INIT).

If none of TEMPG(MAT/INIT) are specified, then the MATi material properties are used.

$T_{F i n a l}$ $T_{F i n a l}$

Load temperature defined by TEMPG(LOAD).

$T_{I n i t i a l}$ $T_{I n i t i a l}$

Initial temperature defined by TEMPG(INIT) or TREF (TREF field on MATi).

TEMPG(INIT) has precedence over TREF. If TEMPG(INIT) is not specified, then TREF is used for the initial temperature.
In Nonlinear Static Analysis, temperature strains and material properties are calculated as 4:
If PARAM, THMLSTN, 0 (Default)
$ε_{T} (t) = A (T_{t}) (T_{t} - T_{I n i t i a l})$ $ε_{T} (t) = A (T_{t}) (T_{t} - T_{I n i t i a l})$
Or, if PARAM, THMLSTN, 1
$ε_{T} = A (T_{F i n a l}) (T_{F i n a l} - T_{R e f}) - A (T_{I n i t i a l}) (T_{I n i t i a l} - T_{r e f})$ $ε_{T} = A (T_{F i n a l}) (T_{F i n a l} - T_{R e f}) - A (T_{I n i t i a l}) (T_{I n i t i a l} - T_{r e f})$
Material properties are also calculated based on their corresponding temperature-dependency (wherever applicable).
Where,

$A (T_{t})$ $A (T_{t})$

Thermal expansion coefficient.

The value of $A (T_{t})$ $A (T_{t})$ 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 TEMPG(LOAD), TEMPG(INIT), or DLOAD(via TLOAD# and TEMP/TEMPD/TEMPADD/TEMPSEC 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.

$T_{t}$ $T_{t}$

Load temperature defined by TEMPG(LOAD) or DLOAD(via TLOAD# and TEMP/TEMPD/TEMPADD/TEMPSEC Bulk Data Entries).

TEMPG(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.

$T_{I n i t i a l}$ $T_{I n i t i a l}$

Initial temperature defined by TEMPG(INIT), or TREF (TREF field on MATi). TEMPG(INIT) has precedence over TREF.

TEMPG(MAT) cannot be used in Nonlinear Static Analysis subcases. OptiStruct errors out if they are specified inside Nonlinear Static Analysis subcases. If TEMPG(MAT) is specified outside Nonlinear Static Subcases (either globally or in subcases of other solution sequences), then TEMPG(LOAD) should be defined inside the Nonlinear Static Subcases in the model.
In Linear Transient Analysis, temperature strains are calculated as (see 2):
$ε_{T} (t) = A (T_{M a t}) (T_{t} - T_{I n i t i a l})$ $ε_{T} (t) = A (T_{M a t}) (T_{t} - T_{I n i t i a l})$
Material properties are also calculated based on their corresponding temperature-dependency (wherever applicable).
Where,

$A (T_{M a t})$ $A (T_{M a t})$

Thermal expansion coefficient.

The value of $A (T_{M a t})$ $A (T_{M a t})$ 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 TEMPG(MAT) or TEMPG(INIT) are specified in conjunction with MATTi entries. If both TEMPG(MAT) and TEMPG(INIT) are specified, TEMPG(MAT) has precedence over TEMPG(INIT).

If neither TEMPG(MAT/INIT) are specified, then the MATi material properties are used.

$T_{t}$ $T_{t}$

Temperature at time t defined via TEMP/TEMP/TEMPD/TEMPSEC Bulk Data Entries via the TLOAD# Bulk Data Entry on a DLOAD Subcase Information Entry.

$T_{I n i t i a l}$ $T_{I n i t i a l}$

Initial temperature defined by TEMPG(INIT) or TREF (TREF field on MATi). TEMPG(INIT) has precedence over TREF.

If TEMPG(INIT) is not specified, then TREF is used for the initial temperature.
In Nonlinear Transient Analysis, temperature strains and material properties are calculated as (see 4):
If PARAM, THMLSTN, 0 (Default)
$ε_{T} (t) = A (T_{t}) (T_{t} - T_{I n i t i a l})$ $ε_{T} (t) = A (T_{t}) (T_{t} - T_{I n i t i a l})$
Or if PARAM, THMLSTN, 1
$ε_{T} (t) = A (T_{t}) (T_{t} - T_{R e f}) - A (T_{I n i t i a l}) (T_{I n i t i a l} - T_{r e f})$ $ε_{T} (t) = A (T_{t}) (T_{t} - T_{R e f}) - A (T_{I n i t i a l}) (T_{I n i t i a l} - T_{r e f})$
Material properties are also calculated based on their corresponding temperature-dependency (wherever applicable).
Where,

$A (T_{t})$ $A (T_{t})$

Thermal expansion coefficient. The value of $A (T_{t})$ $A (T_{t})$ 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 TEMPG(LOAD), TEMP(INIT), or DLOAD(via TLOAD# and TEMP/TEMPD/TEMPADD/TEMPSEC 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.

$T_{t}$ $T_{t}$

Load temperature defined by TEMPG(LOAD) or DLOAD (via TLOAD# and TEMP/TEMPD/TEMPADD/TEMPSEC Bulk Data Entries). TEMPG(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 determines the load temperature for that particular subcase.

$T_{I n i t i a l}$ $T_{I n i t i a l}$

Initial temperature defined by TEMPG(INIT), TREF (TREF field on MATi), or TEMPT Bulk Data Entry. TEMPG(INIT) has precedence over TREF and TEMPT. If TEMPG(INIT) is not specified TREF is used for the initial temperature.

TEMPG(MAT) and TEMPG(LOAD) cannot be used in Nonlinear Transient Analysis subcases. OptiStruct errors out if they are specified inside Nonlinear Transient Analysis subcases. If TEMPG(MAT) or TEMPG(LOAD) are specified outside Nonlinear Transient Subcases (either globally or in subcases of other solution sequences), then DLOAD (via TLOAD# and TEMP/TEMPD/TEMPADD/TEMPSEC Bulk Data Entries) should be defined inside the Nonlinear Transient Subcases in the model.
For Linear Static Subcase, TEMPG(LOAD) or TEMPG(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 is used. When TEMPG(LOAD) 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 TEMPG(INIT) or TEMPG(MAT) entry. For more information, refer to One Step Transient Thermal Stress Analysis.
For Nonlinear Static Subcase, TEMPG(LOAD) can point to heat transfer subcase. The temperature field from a steady-state heat transfer analysis is used to update thermal loading and temperature-dependent material properties. If TEMPG(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 TEMPG(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 TEMPG(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 $A (T)$ $A (T)$ is a secant value. You can obtain its value from the instantaneous thermal expansion coefficient using:
$A (T) = \frac{1}{(T - T_{i n i})} T \int T_{i n i} α (T) d T$ $A (T) = \frac{1}{(T - T_{i n i})} \int_{T_{i n i}}^{T} α (T) d T$
Where,

$T_{i n i}$ $T_{i n i}$

Initial temperature.

$α (T)$ $α (T)$

Instantaneous thermal expansion coefficient.

$A (T)$ $A (T)$

Secant thermal expansion coefficient at temperature $T$ $T$ . This is used by OptiStruct.

When PARAM,THMLSTN,1 is specified, the secant thermal expansion coefficient can be obtained by:
$A (T) = \frac{1}{(T - T_{r e f})} T \int T_{i n i} α (T) d T + A (T_{i n i}) \frac{T_{i n i} - T_{r e f}}{T - T_{r e f}}$ $A (T) = \frac{1}{(T - T_{r e f})} \int_{T_{i n i}}^{T} α (T) d T + A (T_{i n i}) \frac{T_{i n i} - T_{r e f}}{T - T_{r e f}}$
Where, $T_{r e f}$ $T_{r e f}$ is the reference temperature defined on the material entry.
For the initial state, the secant thermal expansion coefficient, $A (T_{i n i}) = α (T_{i n i})$ $A (T_{i n i}) = α (T_{i n i})$ .