TEMPERATURE

Subcase Information Entry

TEMPERATURE – Temperature Set Selection

Description

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

Format

TEMPERATURE (type, HTIME=htime) = option

Examples

TEMPERATURE(LOAD)=15

TEMP(MATERIAL)=7

TEMPERATURE=7

TEMPERATURE(LOAD,HTIME=ALL)=8

Argument	Options	Description
type	<INITIAL, MATERIAL, LOAD, BOTH> Default = BOTH	INITIAL:	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:	Both MATERIAL and LOAD will use the same temperature set.

HTIME	htime = <ALL>	ALL	Selects all the output time steps of a transient thermal subcase.

option	<SID> No default	SID:	Set identification number of TEMP or TEMPD bulk data entries. This can also reference a Transient Heat Transfer subcase or a TSTRU subcase information entry.

Comments

1.	The total load applied will be the sum of external (LOAD command), thermal (TEMP(LOAD/BOTH) command) and constrained displacement (SPC command) loads.

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.

4.	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.

5.	Static and thermal loads should have unique set identification numbers.

6.	In linear static analysis, temperature strains and material properties are calculated as (also see comment 2).

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

Where,

•

A(T) is the thermal expansion coefficient. The value of 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 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.

•

TFinal is the 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.

•	TInitial is the 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.

7. In nonlinear static analysis, temperature strains and material properties are calculated as (also see comment 3):

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

Where,

•

A(T) is the thermal expansion coefficient. The value of A(T) and 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 is used if TEMP(LOAD) is specified in conjunction with MATTi entries. If TEMP(LOAD) is not specified, then TEMP(INIT) is used. If neither TEMP(LOAD) or TEMP(INIT) are specified then the MATi material properties are used.

•

TFinal is the load temperature defined by TEMP(LOAD). 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.

•	TInitial is the 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.

•	TEMP(MAT) and TEMP(BOTH) cannot be used in Nonlinear Static Analysis models. OptiStruct will error out, if they are specified.

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 OptiStruct 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, HTIME= ALL can be used to select temperature fields at all time steps for coupled thermal structural analysis. TEMP(INIT)or TEMP(MAT) cannot be used with HTIME. For more information, refer to One Step Transient Thermal Step Analysis.

10.

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. TEMP(INIT)cannot be used with HTIME. For more information, refer to One Step Transient Thermal Step Analysis.