ansys.mapdl.core.Mapdl.tbft#

Mapdl.tbft(oper='', matid='', option1='', option2='', option3='', option4='', option5='', option6='', option7='', option10='', **kwargs)#

Performs material curve-fitting operations.

Mechanical APDL Command: TBFT

Parameters:

operstr

The operation to perform:

Operation Set 1 (Curve-Fitting) - - - - - - - - - - - - - - - - - - - - -
FADD - Define a constitutive model.
FDEL - Delete a constitutive model.
FSET - Write data related to a constitutive model to the database (same as tb command).
SET - Initialize coefficients of a constitutive model for nonlinear curve-fitting procedure.
CDEL - Deletes coefficients at current reference temperature. Applicable only for temperature- dependent coefficients.
AINI - Automatically initialize coefficients based on elastic properties and experimental data.
SOLVE - Solve for coefficients.
PSOLVE - Custom multistep solve for coefficients.
FIX - Fix (hold constant) the coefficient you specify in Option4.
Operation Set 2 (Experimental Data) - - - - - - - - - - - - - - - - - - - - -
EADD - Add experimental data.
EDEL - Delete experimental data.
Other Operations - - - - - - - - - - - - - - - - - - - - -
LIST - List all data associated with the material model represented by the material ID number ( MATID ).

matidstr

Material reference identification number. (Same as tb, MATID.) Valid value is any number n, where 0 < n < 100,000. Default = 1.

option1str

AML - For curve-fitting function operations ( Oper = Operation Set 1), this value specifies the category.

UNIA - For adding or deleting your experiment (Operation Set 2), this value specifies the experimental data type.

option2str

For curve-fitting function operations ( Oper = Operation Set 1), this value specifies the constitutive model type. The only valid value is GENR (generic).

To obtain experimental data ( Oper = EADD in Operation Set 2) from a file, specify any valid file name. (You can either specify the entire path filename . extension string here and leave Option3 and Option4 blank, or specify filename here, extension in Option3, and path in Option4.)

option3str

For curve-fitting function operations ( Oper = Operation Set 1), specify a unique name for your curve-fitting model.

For obtaining experimental data ( Oper = EADD in Operation Set 2) from a file specified in Option2, specify the file extension.

option4str

When fixing a specific coefficient to a desired value ( Oper = FIX), this value specifies the index of that coefficient. Valid values vary from 1 to n, where n is the total number of coefficients. Default = 1.

For Oper = SET, see tmftableoperset.

You can also specify TREF to indicate the reference temperature, or COMP for a partial/complete solution (only for bulk, only for shear, or all coefficients).

If Oper = SOLVE, this value specifies the curve-fitting procedure. Valid values are 0 for non- normalized least squares curve-fitting procedure, and 1 for normalized least squares curve- fitting procedure.

For obtaining experimental data ( Oper = EADD) from a file specified in Option2, specify the path in which the file resides.

option5str

For Oper = SET, refer to the following table:

Purpose	Option4	Option5
Set the value of the coefficient	Index of coefficient	Value of coefficient
Set temperature dependency ON/OFF	TDEP	1 – ON 0 – OFF
Set reference temperature	TREF	Temperature value

If Oper = SOLVE, use this value to specify the number of iterations to be used in the calculation of the coefficients. Valid value is any positive integer. Default = 1000.

If you are specifying a coefficient to be held constant ( Oper = FIX):

1 - Fix the specified coefficient.
0 - Allow the specified coefficient to vary (disable fixing).

option6str

If Oper = SOLVE, specify the allowed tolerance in residual change to stop an iteration. Valid value is 0.0 to 1.0. Default = 0.0.

option7str

If Oper = SOLVE, specify the allowed tolerance in coefficient change to stop an iteration. Valid value is 0 to 1. Default = 0.

option10str

If Oper = SOLVE, enables parameter scaling when set to 1. Default = 0. Used for creep material curve-fitting.

Notes

Warning

This function contains specificities regarding the argument definitions. Please refer to the command documentation for further explanations.

*TBFT Specifications for Hyperelastic Models*

tbft, Oper, MATID, Option1, Option2, Option3, Option4, Option5, Option6, Option7

Oper - The operation to perform:
- Operation Set 1 (Curve-Fitting) - - - - - - - - - - - - - - - - - - - - -
- FADD - Define a constitutive model for parameter fitting and import all parameters (defined previously via tb and tbdata ).
- FDEL - Delete a constitutive model.
- FSET - Write data related to a constitutive model to the database (same as tb command).
- SET - Initialize coefficients of a constitutive model for nonlinear curve-fitting procedure.
- CDEL - Deletes coefficients at current reference temperature. Applicable only for temperature dependent coefficients.
- SOLVE - Solve for coefficients.
- FIX - Fix (hold constant) the coefficient you specify in Option4.
- Operation Set 2 (Experimental Data) - - - - - - - - - - - - - - - - - - - - -
- EADD - Add experimental data.
- EDEL - Delete experimental data.
- Other Operations - - - - - - - - - - - - - - - - - - - - -
- LIST - List all data associated with the material model represented by the material ID number ( MATID )
MATID - Material reference identification number (same as MAT argument used in the tb command). Valid value is any number n, where 0 < n < 100,000. Default = 1.
Option1 - For curve-fit function operations ( Oper = FADD, FDEL, FSET, SET, CDEL, SOLVE or

FIX) this value

specifies the category (AML).

For adding or deleting your experiment ( Oper = EADD or EDEL), this value specifies the experimental data type. Valid options: UNIA (default), BIAX, SHEA, SSHE,and VOLU.

Option2 - For curve-fit function operations ( Oper = FADD, FDEL, FSET, SET, CDEL, SOLVE, or FIX), set this value to GENR.

When you need to specify a file name from which to get experimental data ( Oper = EADD), place that string here. Valid value is any file name string. You can enter the entire pathfilename.extension string and leave the next two values ( Option3 and Option4 ) blank, or you can specify the name here, the extension in the next value, and the path following.
Option3 - For Oper = FADD, FDEL, FSET, CDEL, SET, SOLVE or FIX, set this value to a user- defined name (to be used consistently in the curve-fitting process).

If a file name for experimental data is being specified in Option2 ( Oper = EADD), this value will contain the file extension.
Option4 - When you are working on a specific coefficient ( Oper = FIX), this value specifies the index of that coefficient. Valid values vary from 1 to n, where n is the total number of coefficients. Default = 1.

For Oper = SET, see tbfthypsetvals, below.

If a file name for experimental data is being specified in Option2 ( Oper = EADD), this value will contain the directory/path specification.

If Oper = SOLVE, this value specifies the curve-fitting procedure. Valid values are 0 for non- normalized least squares curve-fitting procedure, and 1 for normalized least squares curve-fitting procedure.
Option5 - When you are working on a specific coefficient ( Oper = FIX), this value

specifies the index of

that coefficient. Valid values vary from 1 to N, where N is the total number of coefficients. Default = 1.

For Oper = SET, see tbfthypsetvals, below.

Purpose	Option4	Option5
Set the value of the coefficient.	Index of coefficient	Value of that coefficient
Set temperature dependency ON/OFF Specify temperature data in the same specified via tref.	TDEP	1 – ON 0 – OFF
Set reference temperature	TREF	Temperature value

If Oper = SOLVE, use this value to specify the number of iterations to be used in the calculation of the coefficients. Valid value is any positive integer. Default = 1000.

Option6 - If Oper = SOLVE, specifies the allowed tolerance in residual change to stop an iteration. Valid value is 0.0 to 1.0. Default = 0.0.
Option7 - If Oper = SOLVE, specifies the allowed tolerance in coefficient change to stop an iteration. Valid value is 0 to 1. Default = 0.

For the supported list of material models, see.

This table summarizes the format for hyperelastic curve-fitting operations via tbft :

Hyperelastic Model Command Summary#

This command contains some tables and extra information which can be inspected in the original documentation pointed above.

*TBFT Specifications for Viscoelastic Models*

tbft, Oper, MATID, Option1, Option2, Option3, Option4, Option5, Option6, Option7

Oper - The operation to perform:
- Operation Set 1 (Curve-Fitting) - - - - - - - - - - - - - - - - - - - - -
- FADD - Define a constitutive model.
- FDEL - Delete a constitutive model.
- FSET - Write data related to a constitutive model to the database (same as tb command).
- SET - Initialize coefficients of a constitutive model for nonlinear curve-fitting procedure.
- CDEL - Deletes coefficients at current reference temperature. Applicable only for temperature dependent coefficients.
- SOLVE - Solve for coefficients.
- FIX - Fix (hold constant) the coefficient you specify in Option4.
- Operation Set 2 (Experimental Data) - - - - - - - - - - - - - - - - - - - - -
- EADD - Add experimental data.
- EDEL - Delete experimental data.
- Other Operations - - - - - - - - - - - - - - - - - - - - -
- LIST - List all data associated with the material model represented by the material ID number ( MATID )
MATID - Material reference identification number (same as MAT argument used in the tb command). Valid value is any number n, where 0 < n < 100,000. Default = 1.
Option1 - For curve-fitting function operations ( Oper = FADD, FDEL, FSET, SET, CDEL,

SOLVE, or FIX), this

value is set to AML.

For adding or deleting your experiment ( Oper = EADD or EDEL), this value specifies the experiment type. Valid options: SDEC (Shear Modulus vs. Time/Freq) or BDEC (Bulk Modulus vs. Time/Freq).

Option2 - For curve-fitting function operations ( Oper = FADD, FDEL, FSET, SET, CDEL, SOLVE, or FIX), this value is set to GENR.

When you need to specify a file name from which to get experimental data ( Oper = EADD), place that string here. Valid value is any file name string. You can enter the entire pathfilename.extension string and leave the next two values ( Option3 and Option4 ) blank, or you can specify the name here, the extension in the next value, and the path following.
Option3 - For Oper = FADD, FDEL, FSET, CDEL, SET, SOLVE, or FIX, set this value to any user-defined name (to be used consistently during the curve-fitting process).

If a file name for experimental data is being specified in Option2 ( Oper = EADD), this value will contain the file extension.
Option4 - When you are working on a specific coefficient ( Oper = FIX), this value specifies the index of that coefficient. Valid values vary from 1 to n, where n is the total number of coefficients. Default = 1.

For Oper = SET, see tbftvscsetvals below.

You can also specify TREF to indicate the reference temperature.

If a file name for experimental data is being specified in Option2 ( Oper = EADD), this value will contain the directory/path specification.

If Oper = SOLVE, this value specifies the curve-fitting procedure. Valid values are 0 for non- normalized least squares curve-fitting procedure, and 1 for normalized least squares curve-fitting procedure.

Option5 - For Oper = SET, see tbftvscsetvals below.

Purpose	Option4	Option5
Set the value of the coefficient	Index of coefficient	Value of coefficient
Set temperature dependency ON/OFF	TDEP	1 for ON and 0 for OFF
Set reference temperature	TREF	Temperature value

If Oper = SOLVE, use this value to specify the number of iterations to be used in the calculation of the coefficients. Valid value is any positive integer. Default = 1000.

If you are specifying a coefficient to be held constant ( Oper = FIX):

1 - Fix the specified coefficient.
0 - Allow the specified coefficient to vary (disable fixing).

Option6 - If Oper = SOLVE, specifies the allowed tolerance in residual change to stop an iteration. Valid value is 0.0 to 1.0. Default = 0.0.
Option7 - If Oper = SOLVE, specifies the allowed tolerance in coefficient change to stop an iteration. Valid value is 0 to 1. Default = 0.

This table summarizes the format for viscoelastic curve-fitting operations via tbft :

Viscoelastic Model Command Summary#

This command contains some tables and extra information which can be inspected in the original documentation pointed above.

*TBFT Specifications for Chaboche Kinematic Hardening Plasticity Models*

tbft, Oper, MATID, Option1, Option2, Option3, Option4, Option5, Option6, Option7, -, -, Option10

Oper - The operation to perform:
- Operation Set 1 (Curve-Fitting) - - - - - - - - - - - - - - - - - - - - -
- FCASE - Define a case/constitutive model for plasticity.
- FADD - Define a constitutive model.
- FDEL - Delete a constitutive model.
- FSET - Write data related to a constitutive model to the database (same as tb command).
- SET - Initialize coefficients of a constitutive model for nonlinear curve-fitting procedure.
- CDEL - Deletes coefficients at current reference temperature. Applicable only for temperature- dependent coefficients.
- SOLVE - Solve for coefficients.
- FIX - Fix (hold constant) the coefficient you specify in Option4.
- Operation Set 2 (Experimental Data) - - - - - - - - - - - - - - - - - - - - -
- EADD - Add experimental data.
- EDEL - Delete experimental data.
- Other Operations - - - - - - - - - - - - - - - - - - - - -
- LIST - List all data associated with the material model represented by the material ID number ( MATID ).
MATID - Material reference identification number (same as MAT argument used in the tb command). Valid value is any number greater than zero (default = 1) but less than 100,000.
Option1 - For Oper = FCASE, set to either NEW or FINI. The command tbft,FCASE, MATID,NEW initializes a new curve-fitting case. (The tbft,FADD commands described next are always issued between tbft,FCASE, MATID,NEW and tbft,FCASE, MATID,FINI commands.) After issuing tbft,FCASE, MATID,FINI, the Chaboche model is created and is ready to be used to perform other curve-fitting operations. For more information, see Material Curve-Fitting

For Oper = FADD, set to PLAS to add options/parameters for the new case being created (via tbft,FCASE, MATID,NEW, which must be issued before the tbft,FADD command). This operation specifies the order of the Chaboche kinematic model.

For other curve-fitting function operations ( Oper = FDEL, FSET, SET, CDEL, SOLVE or FIX), set to CASE.

For adding or deleting your experiment ( Oper = EADD or EDEL), this option specifies the experiment type. The only valid option is UNIA (plastic strain vs. true stress).
Option2 - For Oper = FCASE (defining your Chaboche case), set to CPLA.

For Oper = FDEL, FSET, SET, CDEL, SOLVE, or FIX (curve-fitting function operations), this value specifies the case name being operated on.

For Oper = FADD (specifying options for the plasticity model), valid options are:
- CHAB – Chaboche kinematic hardening (required for any defined curve-fitting case)
- BISO – Bilinear isotropic hardening (optional)
- MISO – Multilinear isotropic hardening (optional)
- VOCE – Nonlinear isotropic hardening, Voce model (optional)
- The tbft,FADD command can be issued twice, once to specify the order of the Chaboche model, and again to specify the isotropic hardening option. (Only one of the options BISO, MISO or VOCE can be used in a single curve-fitting case, and none of those options are required.)
For Oper = EADD (specifying a file name from which to get experimental data), place that string here. A valid entry is any file name string. You can either:
- Enter the entire pathfilename.extension string and leave the next two values ( Option3 and Option4 ) blank, or
- Specify the name here, the extension in the next value, and the path in the following value.
Option3 - For Oper = FCASE, this value specifies the case name.

For Oper = FADD, this value specifies either:
- The order of the Chaboche kinematic hardening model ( Option2 = CHAB), or
- The number of terms in the MISO model ( Option2 = MISO).
If a file name for experimental data is being specified in Option2 ( Oper = EADD), this value contains the file extension.
Option4 - When fixing a specific coefficient to a desired value ( Oper = FIX), this value specifies the index of that coefficient. Valid values vary from 1 to n, where n is the total number of coefficients. Default = 1.

For Oper = SET, see tbftvscsetvals.

You can also specify TREF to indicate the reference temperature, or COMP for a partial/complete solution (only for bulk, only for shear, or all coefficients).

If a file name for experimental data is being specified in Option2 ( Oper = EADD), this value contains the directory/path specification.

If Oper = SOLVE, this value specifies the normalized/non-normalized option. This option is not available for Chaboche curve-fitting.

Option5 - For Oper = SET, refer to the following table.

Purpose	Option4	Option5
Set the value of the coefficient	Index of coefficient	Value of coefficient
Set temperature dependency ON/OFF	TDEP	1 for ON and 0 for OFF
Set reference temperature	TREF	Temperature value

If Oper = SOLVE, use this value to specify the number of iterations to be used in the calculation of the coefficients. Valid value is any positive integer. Default = 1000.

If you are specifying a coefficient to be held constant ( Oper = FIX):

1 - Fix the specified coefficient.
0 - Allow the specified coefficient to vary (disable fixing).

Option6 - If Oper = SOLVE, specifies the allowed tolerance in residual change to stop an iteration. Valid value is 0.0 to 1.0. Default = 0.0.
Option7 - If Oper = SOLVE, specifies the allowed tolerance in coefficient change to stop an iteration. Valid value is 0 to 1. Default = 0.
- - Reserved for future use.
- - Reserved for future use.
Option10 - If Oper = SOLVE, enables parameter scaling when set to 1. Default = 0. Used for Chaboche material curve-fitting.

This table summarizes the format for Chaboche curve-fitting operations via tbft :

Chaboche Model Command Summary#

This command contains some tables and extra information which can be inspected in the original documentation pointed above.

*TBFT Specifications for Creep Models*

tbft, Oper, MATID, Option1, Option2, Option3, Option4, Option5, Option6, Option7, -, -, Option10

Oper - The operation to perform:
- Operation Set 1 (Curve-Fitting) - - - - - - - - - - - - - - - - - - - - -
- FADD - Define a constitutive model.
- FDEL - Delete a constitutive model.
- FSET - Write data related to a constitutive model to the database (same as tb command).
- SET - Initialize coefficients of a constitutive model for nonlinear curve-fitting procedure.
- CDEL - Deletes coefficients at current reference temperature. Applicable only for temperature dependent coefficients.
- SOLVE - Solve for coefficients.
- FIX - Fix (hold constant) the coefficient you specify in Option4.
- Operation Set 2 (Experimental Data) - - - - - - - - - - - - - - - - - - - - -
- EADD - Add experimental data.
- EDEL - Delete experimental data.
- Other Operations - - - - - - - - - - - - - - - - - - - - -
- LIST - List all data associated with the material model represented by the material ID number ( MATID )
MATID - Material reference identification number (same as MAT argument used in the tb command). Valid value is any number n, where 0 < n < 100,000. Default = 1.
Option1 - For curve-fit function operations ( Oper = FADD, FDEL, FSET, SET, CDEL, SOLVE or FIX) this value specifies the category (CREEP).

For adding or deleting your experiment ( Oper = EADD or EDEL), this value specifies the experimental data type (CREEP).
Option2 - For curve-fit function operations ( Oper = FADD, FDEL, FSET, SET, CDEL, SOLVE, or FIX), this value specifies constitutive model type. The valid values are listed in Creep Options below.

When you need to specify a file name from which to get experimental data ( Oper = EADD), place that string here. Valid value is any file name string. You can enter the entire pathfilename.extension string and leave the next two values ( Option3 and Option4 ) blank, or you can specify the name here, the extension in the next value, and the path following.
Option3 - If a file name for experimental data is being specified in Option2 ( Oper = EADD), this value will contain the file extension.
Option4 - When you are working on a specific coefficient ( Oper = FIX), this value, specifies the index of that coefficient. Valid values vary from 1 to n, where n is the total number of coefficients. Default = 1.

For Oper = SET, see tbftcrpsetvals, below.

If a file name for experimental data is being specified in Option2 ( Oper = EADD), this value will contain the directory/path specification.

If Oper = SOLVE, this value specifies the curve-fitting procedure. Valid values are 0 for non- normalized least squares curve-fitting procedure, and 1 for normalized least squares curve-fitting procedure.
Option5 - If Oper = SOLVE, use this value to specify the number of iterations to be used

in the

calculation of the coefficients. Valid value is any positive integer. Default = 1000.

If you are specifying a coefficient to be held constant ( Oper = FIX):

1 - Fix the specified coefficient.
0 - Allow the specified coefficient to vary (disable fixing).

For Oper = SET, see tbftcrpsetvals, below.

Purpose	Option4	Option5
Set the value of the coefficient	Index of coefficient	Value of coefficient
Set temperature dependency ON When TDEP is OFF, the Arrhenius term (C4) in the strain-hardening creep equation is calculated. Because tbtemp is not included in the curve-fitting, the experimental data (in absolute temperature) must be provided via `/TEMP`. /OFF When TDEP is ON, the Arrhenius term is set to 0 and the constants are calculated separately for each temperature. The curve-fitting process uses tbtemp. You must provide the experimental data using the same units as specified via tref.	TDEP	1 – ON 0 – OFF
Set reference temperature	TREF	Temperature value

Option6 - If Oper = SOLVE, specifies the allowed tolerance in residual change to stop an iteration. Valid value is 0.0 to 1.0. Default = 0.0.
Option7 - If Oper = SOLVE, specifies the allowed tolerance in coefficient change to stop an iteration. Valid value is 0 to 1. Default = 0.
- - Reserved for future use.
- - Reserved for future use.
Option10 - If Oper = SOLVE, enables parameter scaling when set to 1. Default = 0. Used for creep material curve-fitting.

Creep Options#

Category	Name	Option
CREEP	SHAR	NA
CREEP	THAR	NA
CREEP	GEXP	NA
CREEP	GGRA	NA
CREEP	GBLA	NA
CREEP	MTHA	NA
CREEP	MSHA	NA
CREEP	GGAR	NA
CREEP	EXPO	NA
CREEP	NORT	NA
CREEP	PSTH	NA
CREEP	PSRP	NA
CREEP	GTHA	NA

This table summarizes the format for creep curve-fitting operations via tbft :

Creep Model Command Summary#

This command contains some tables and extra information which can be inspected in the original documentation pointed above.

*TBFT Specifications for Thermomechanical Fatigue (TMF)and Plasticity Model Combinations*

tbft, Oper, MATID, Option1, Option2, Option3, Option4, Option5, Option6, Option7

Oper - The operation to perform:
- Operation Set 1 (Curve-Fitting) - - - - - - - - - - - - - - - - - - - - -
- FADD - Define a constitutive model.
- FDEL - Delete a constitutive model.
- FSET - Write data related to a constitutive model to the database (same as tb command).
- SET - Initialize coefficients of a constitutive model for nonlinear curve-fitting procedure.
- CDEL - Deletes coefficients at current reference temperature. Applicable only for temperature- dependent coefficients.
- AINI - Automatically initialize coefficients based on elastic properties and experimental data.
- SOLVE - Solve for coefficients.
- PSOLVE - Custom multistep solve for coefficients.
- FIX - Fix (hold constant) the coefficient you specify in Option4.
- Operation Set 2 (Experimental Data) - - - - - - - - - - - - - - - - - - - - -
- EADD - Add experimental data.
- EDEL - Delete experimental data.
- Other Operations - - - - - - - - - - - - - - - - - - - - -
- LIST - List all data associated with the material model represented by the material ID number ( MATID ).
MATID - Material reference identification number. (Same as tb, MATID.) Valid value is any number n, where 0 < n < 100,000. Default = 1.
Option1 - AML - For curve-fitting function operations ( Oper = Operation Set 1), this value specifies the category.

UNIA - For adding or deleting your experiment (Operation Set 2), this value specifies the experimental data type.
Option2 - For curve-fitting function operations ( Oper = Operation Set 1), this value specifies the constitutive model type. The only valid value is GENR (generic).

To obtain experimental data ( Oper = EADD in Operation Set 2) from a file, specify any valid file name. (You can either specify the entire path filename . extension string here and leave Option3 and Option4 blank, or specify filename here, extension in Option3, and path in Option4.)
Option3 - For curve-fitting function operations ( Oper = Operation Set 1), specify a unique name for your curve-fitting model.

For obtaining experimental data ( Oper = EADD in Operation Set 2) from a file specified in Option2, specify the file extension.
Option4 - When fixing a specific coefficient to a desired value ( Oper = FIX), this value specifies the index of that coefficient. Valid values vary from 1 to n, where n is the total number of coefficients. Default = 1.

For Oper = SET, see tmftableoperset.

You can also specify TREF to indicate the reference temperature, or COMP for a partial/complete solution (only for bulk, only for shear, or all coefficients).

If Oper = SOLVE, this value specifies the curve-fitting procedure. Valid values are 0 for non- normalized least squares curve-fitting procedure, and 1 for normalized least squares curve-fitting procedure.

For obtaining experimental data ( Oper = EADD) from a file specified in Option2, specify the path in which the file resides.

Option5 - For Oper = SET, refer to the following table:

Purpose	Option4	Option5
Set the value of the coefficient	Index of coefficient	Value of coefficient
Set temperature dependency ON/OFF	TDEP	1 – ON 0 – OFF
Set reference temperature	TREF	Temperature value

If Oper = SOLVE, use this value to specify the number of iterations to be used in the calculation of the coefficients. Valid value is any positive integer. Default = 1000.

If you are specifying a coefficient to be held constant ( Oper = FIX):

1 - Fix the specified coefficient.
0 - Allow the specified coefficient to vary (disable fixing).

Option6 - If Oper = SOLVE, specify the allowed tolerance in residual change to stop an iteration. Valid value is 0.0 to 1.0. Default = 0.0.
Option7 - If Oper = SOLVE, specify the allowed tolerance in coefficient change to stop an iteration. Valid value is 0 to 1. Default = 0.

Supported Material Models#

This command contains some tables and extra information which can be inspected in the original documentation pointed above.

The tbft command provides tools for comparing experimental material data to the program- provided calculated data for various nonlinear material options. Based on curve-fitting comparisons and error norms, choose the model to use during the solution phase of the analysis according to the best fit. All of the capabilities of the tbft command are accessible interactively via the standard material GUI. For more information, see Material Curve-Fitting

Display material model data associated with both the tb command and the tbft,FSET command via tblist,ALL,ALL.

Material model data associated with the most recent tb or tbft,FSET command overwrites previous data.

Display material model data associated with both the tb command and the tbft,FSET command via tblist,ALL,ALL.

The capability to fix coefficients ( Option4 = FIX) applies only to nonlinear curve fitting (as listed in.

The uniaxial, biaxial, and shear experimental data use engineering stress. The volumetric data uses true stress. See the Material Reference for details about experimental data for creep and viscoelasticity.

The hyperelastic option AML,GENR is a generalized framework where the parameters (defined prior to issuing tbft ) are imported directly from tb and tbdata. Parameter-fitting uses this framework for the thermomechanical fatigue, geomechanical, and TNM material models.

tbft does not support saving to ( save ) and resuming from ( resume ) the database file. You must therefore rerun the curve-fitting analysis and then replot ( tbfplot ).