TEMPERATURE

Format

TEMPERATURE (type, SUBTYPE=subtype_option) = option

Examples

TEMPERATURE(LOAD)=15
TEMP(MATERIAL)=7
TEMPERATURE=7
TEMPERATURE(LOAD,HTIME=ALL)=8
TEMPERATURE(LOAD,TEMPT)=23

Definitions

Comments

1. 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.
2. 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/TEMPSEC 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/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 TEMP(MAT) and TEMP/TEMPD/TEMPADD/TEMPSEC 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.	NA
   Temperature Loading for NL Subcase in OSTTS	NA	NA	TEMP(LOAD,HTIME) or TEMP(LOAD,TEMPT)	TEMP(LOAD,TEMPT)	NA
   Initial Temperature for NL Subcase in OSTTS	NA	NA	TREF, TEMP(INIT)	TREF or TEMP(INIT)	NA
   Temperature-dependent material	TEMP(INIT), TEMP(MAT), or TEMP(BOTH)	TEMP(INIT) or TEMP(MAT)	TEMP(INIT), TEMP(LOAD), TEMP(LOAD,TEMPT), TEMP(LOAD,HTIME) or DLOAD (via TLOAD# + TEMP/TEMPD/TEMPADD Bulk)	TEMP(INIT), TEMP(LOAD,TEMPT), TEMP(LOAD,HTIME), or DLOAD (via TLOAD# + TEMP/TEMPD/TEMPADD Bulk)	NA

3. 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.
4. 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.
5. 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.
6. Static and thermal loads should have unique set identification numbers.
7. In Linear Static Analysis, temperature strains and material properties are calculated as: 3

   $${\epsilon }_T=A\left(T_{Mat}\right)\left(T_{Final}-T_{Initial}\right)$$

   Material properties are also calculated based on their corresponding temperature-dependency (wherever applicable).

   Where,

   $A(T_{Mat})$

   Thermal expansion coefficient.

   The value of $A(T_{Mat})$ 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.

   $T_{Final}$

   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.

   $T_{Initial}$

   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.

8. In Nonlinear Static Analysis, temperature strains and material properties are calculated as: 4
   If PARAM, THMLSTN, 0 (Default)

   $${\epsilon }_T\left(t\right)=A\left(T_t\right)\left(T_t-T_{Initial}\right)$$

   Or, if PARAM, THMLSTN, 1

   $${\epsilon }_T=A\left(T_{Final}\right)\left(T_{Final}-T_{Ref}\right)-A\left(T_{Initial}\right)\left(T_{Initial}-T_{ref}\right)$$

   Material properties are also calculated based on their corresponding temperature-dependency (wherever applicable).

   Where,

   $A(T_t)$

   Thermal expansion coefficient.

   The value of $A(T_t)$ 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 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.

   $T_t$

   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.

   $T_{Initial}$

   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.

9. In Linear Transient Analysis, temperature strains are calculated as: 2

   $${\epsilon }_T\left(t\right)=A\left(T_{Mat}\right)\left(T_t-T_{Initial}\right)$$

   Material properties are also calculated based on their corresponding temperature-dependency (wherever applicable).
   Where,

   $A(T_{Mat})$

   Thermal expansion coefficient.

   The value of $A(T_{Mat})$ 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.

   $T_t$

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

   $T_{Initial}$

   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.

10. In Nonlinear Transient Analysis, temperature strains and material properties are calculated as: 3
    If PARAM, THMLSTN, 0 (Default)

    $${\epsilon }_T\left(t\right)=A\left(T_t\right)\left(T_t-T_{Initial}\right)$$

    Or if PARAM, THMLSTN, 1

    $${\epsilon }_T\left(t\right)=A\left(T_t\right)\left(T_t-T_{Ref}\right)-A\left(T_{Initial}\right)\left(T_{Initial}-T_{ref}\right)$$

    Material properties are also calculated based on their corresponding temperature-dependency (wherever applicable).
    Where,

    $A(T_t)$

    Thermal expansion coefficient. The value of $A(T_t)$ 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 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.

    $T_t$

    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.

    $T_{Initial}$

    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.

11. 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.
12. 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.
13. 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.
14. 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.
15. In Nonlinear Analysis, the thermal expansion coefficient $A\left(T\right)$ is a secant value. You can obtain its value from the instantaneous thermal expansion coefficient using:

    $$A\left(T\right)=\frac{1}{\left(T-T_{ini}\right)}{\displaystyle \underset{T_{ini}}{\overset{T}{\int }}\alpha \left(T\right)dT}$$

    Where,

    $T_{ini}$

    Initial temperature.

    $\alpha \left(T\right)$

    Instantaneous thermal expansion coefficient.

    $A\left(T\right)$

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

    When PARAM,THMLSTN,1 is specified, the secant thermal expansion coefficient can be obtained by:

    $$A\left(T\right)=\frac{1}{\left(T-T_{ref}\right)}{\displaystyle \underset{T_{ini}}{\overset{T}{\int }}\alpha \left(T\right)dT}+A\left(T_{ini}\right)\frac{T_{ini}-T_{ref}}{T-T_{ref}}$$

    Where, $T_{ref}$ is the reference temperature defined on the material entry.

    For the initial state, the secant thermal expansion coefficient, $A\left(T_{ini}\right)=\alpha \left(T_{ini}\right)$ .

16. 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.
17. 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.
18. This TEMP entry can also be used to point to a TEMPSEC Bulk Data Entry to reference layer-based temperature for shell elements. The loading applied with TEMPSEC can be output with OLOAD(NDIV=n)=YES.