# *EXPANSION

 Specify thermal or field expansion. This option is used to define thermal expansion or field expansion in Abaqus/Standard for a material or for the behavior of a gasket. In an Abaqus/Standard analysis spatially varying thermal expansion can be defined for solid continuum elements using a distribution (Distribution definition).
 Related Topics *TRS In Other Guides Thermal expansion Field expansion UEXPAN VUEXPAN

ProductsAbaqus/StandardAbaqus/ExplicitAbaqus/CAE

TypeModel data

LevelModel

Abaqus/CAEProperty module

## Optional parameters

DEPENDENCIES

This parameter applies only to Abaqus/Standard and Abaqus/Explicit analyses.

Set this parameter equal to the number of field variables, in addition to temperature, on which the coefficients depend. If this parameter is omitted, it is assumed that the thermal expansion is constant or depends only on temperature.

This parameter is not relevant if the USER parameter is included or if in an Abaqus/Standard analysis spatially varying thermal expansion is defined using a distribution (see Distribution definition).

FIELD

This parameter applies only to Abaqus/Standard analyses.

Set this parameter equal to the predefined field variable number for which field expansion is being defined.

LIQUID
This parameter applies only to Abaqus/Standard analyses.

Include this parameter if the thermal expansion of the liquid is being defined for the TNM model.

PORE FLUID

This parameter applies only to Abaqus/Standard analyses.

Include this parameter if the thermal expansion of the pore fluid in a porous medium is being defined. The thermal expansion of a fluid must be isotropic, so TYPE=ORTHO and TYPE=ANISO cannot be used if this parameter is included.

PROPERTIES

This parameter applies only to Abaqus/Explicit analyses.

Set this parameter equal to the number of properties being entered. The properties are available for use in user subroutine VUEXPAN. The default is PROPERTIES=0.
TYPE

Set TYPE=ISO (default) to define isotropic expansion.

Set TYPE=ORTHO to define orthotropic expansion.

Set TYPE=ANISO to define fully anisotropic expansion in an Abaqus/Standard analysis. In Abaqus/Explicit fully anisotropic expansion is supported only with user-defined expansion.

Set TYPE=SHORT FIBER to define laminate material properties for each layer in each shell element. This parameter setting is applicable only when using Abaqus/Standard in conjunction with the abaqus moldflow execution procedure. Any data lines will be ignored. Material properties will be read from the ASCII neutral file identified as jobid.shf. See Translating Moldflow data to Abaqus input files for more information.

In an Abaqus/Standard analysis spatially varying isotropic, orthotropic, or anisotropic expansion can be defined using a distribution. When using a distribution, the TYPE parameter must be used to indicate the level of anisotropy of thermal expansion. The level of anisotropy must be consistent with that defined in the distribution. See Distribution definition.

USER

Include this parameter to indicate that user subroutine UEXPAN in Abaqus/Standard and VUEXPAN in Abaqus/Explicit will be used to define increments of thermal strain. The TYPE parameter should be used to indicate the level of anisotropy of thermal expansion. The PORE FLUID parameter can also be used to indicate that the thermal expansion of the pore fluid is being defined.

The DEPENDENCIES and ZERO parameters are not relevant if this parameter is used.

ZERO

If the thermal expansion is temperature- or field-variable-dependent, set this parameter equal to the value of $θ0$. The default is ZERO=0.

This parameter is not relevant if the USER parameter is included.

## Data lines to define isotropic thermal expansion coefficients (TYPE=ISO with USER parameter omitted)

First line
1. $α$ in Abaqus/Standard or Abaqus/Explicit analysis. (Units of $θ$−1.)

2. Temperature.

3. First field variable.

4. Etc., up to six field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than six)
1. Seventh field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the thermal expansion coefficient as a function of temperature and other predefined field variables.

## Data lines to define orthotropic thermal expansion coefficients (TYPE=ORTHO with USER parameter omitted)

First line
1. $α11$. (Units of $θ$−1.)

2. $α22$.

3. $α33$. (Not used for plane stress and shell cases.)

4. Temperature.

5. First field variable.

6. Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four)
1. Fifth field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the thermal expansion coefficients as functions of temperature and other predefined field variables.

## Data lines to define anisotropic thermal expansion coefficients (TYPE=ANISO with USER parameter omitted)

First line
1. $α11$. (Units of $θ$−1.)

2. $α22$.

3. $α33$. (Not used for plane stress and shell cases.)

4. $α12$.

5. $α13$. (Not used for plane stress and shell cases.)

6. $α23$. (Not used for plane stress and shell cases.)

7. Temperature.

8. First field variable.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than one)
1. Second field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the thermal expansion coefficients as functions of temperature and other predefined field variables.

## Data line to define spatially varying thermal expansion in an Abaqus/Standard analysis using a distribution

First (and only) line
1. Distribution name. The data defined in the distribution must be in units of $θ$−1 and must be consistent with the level of anisotropy prescribed by the TYPE parameter.

## To define thermal expansion by a user subroutine (USER parameter included)

No data lines are used with this option when the USER parameter is specified. Instead, user subroutine UEXPAN must be used to define the thermal expansion. In Abaqus/Explicit data lines can be used to specify user properties that are passed in user subroutine VUEXPAN to define the thermal expansion.

## Data lines to define isotropic field expansion coefficients (TYPE=ISO with USER parameter omitted)

First line
1. $αf$. (Units of $F⁢Vn$−1.)

2. Temperature.

3. First field variable.

4. Etc., up to six field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than six)
1. Seventh field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the field expansion coefficient as a function of temperature and other predefined field variables.

## Data lines to define orthotropic field expansion coefficients (TYPE=ORTHO with USER parameter omitted)

First line
1. $αf11$. (Units of $F⁢Vn$−1.)

2. $αf22$.

3. $αf33$.

4. Temperature.

5. First field variable.

6. Etc., up to four field variables.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than four)
1. Fifth field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the field expansion coefficients as functions of temperature and other predefined field variables.

## Data lines to define anisotropic field expansion coefficients (TYPE=ANISO with USER parameter omitted)

First line
1. $αf11$. (Units of $F⁢Vn$−1.)

2. $αf22$.

3. $αf33$. (Not used for plane stress case.)

4. $αf12$.

5. $αf13$.

6. $αf23$.

7. Temperature.

8. First field variable.

Subsequent lines (only needed if the DEPENDENCIES parameter has a value greater than one)
1. Second field variable.

2. Etc., up to eight field variables per line.

Repeat this set of data lines as often as necessary to define the field expansion coefficients as functions of temperature and other predefined field variables.

## To define field expansion by a user subroutine (USER parameter included)

No data lines are used with this option when the USER parameter is specified. Instead, user subroutine UEXPAN must be used to define the field expansion.