# Compute Volumetric Eigenstrain

Computes an eigenstrain that is defined by a set of scalar material properties that summed together define the volumetric change. This also computes the derivatives of that eigenstrain with respect to a supplied set of variable dependencies.

## Description

This material computes the eigenstrain tensor based on a set of scalar material properties which when summed together define the volumetric strain. The materials taken as input to this model specify the ratio , where is the current volume and is the initial volume.

In models that use finite strain formulations, the volume change resulting from this eigenstrain will exactly equal the specified volumetric strain.

## Example Input File Syntax

[./volumetric_eigenstrain]
type = ComputeVolumetricEigenstrain
volumetric_materials = volumetric_change
eigenstrain_name = eigenstrain
args = ''
[../]

(modules/tensor_mechanics/test/tests/volumetric_eigenstrain/volumetric_eigenstrain.i)

where the volumetric material is defined as a separate material model

[./volumetric_change]
type = GenericFunctionMaterial
prop_names = volumetric_change
prop_values = t
[../]

(modules/tensor_mechanics/test/tests/volumetric_eigenstrain/volumetric_eigenstrain.i)

The eigenstrain_name parameter value must also be set for the strain calculator. When the TensorMechanics/Master Action is used, it automatically creates the strain calculator. In that case, the eigenstrain_name is specified in the Master action block, and passed in to the strain calculator as shown:

[Modules/TensorMechanics/Master]
[./master]
use_displaced_mesh = true
strain = FINITE
eigenstrain_names = eigenstrain
decomposition_method = EigenSolution #Necessary for exact solution
[../]
[]

(modules/tensor_mechanics/test/tests/volumetric_eigenstrain/volumetric_eigenstrain.i)

## Input Parameters

• eigenstrain_nameMaterial property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.

C++ Type:std::string

Options:

Description:Material property name for the eigenstrain tensor computed by this model. IMPORTANT: The name of this property must also be provided to the strain calculator.

• argsvariable dependencies for the volumetric_expansion

C++ Type:std::vector

Options:

Description:variable dependencies for the volumetric_expansion

• volumetric_materialsList of scalar materials defining the volumetric change

C++ Type:std::vector

Options:

Description:List of scalar materials defining the volumetric change

### Required Parameters

• blockThe list of block ids (SubdomainID) that this object will be applied

C++ Type:std::vector

Options:

Description:The list of block ids (SubdomainID) that this object will be applied

• boundaryThe list of boundary IDs from the mesh where this boundary condition applies

C++ Type:std::vector

Options:

Description:The list of boundary IDs from the mesh where this boundary condition applies

• computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

Default:True

C++ Type:bool

Options:

Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

• base_nameOptional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

C++ Type:std::string

Options:

Description:Optional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

### Optional Parameters

• output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)

C++ Type:std::vector

Options:

Description:List of material properties, from this material, to output (outputs must also be defined to an output type)

• outputsnone Vector of output names were you would like to restrict the output of variables(s) associated with this object

Default:none

C++ Type:std::vector

Options:

Description:Vector of output names were you would like to restrict the output of variables(s) associated with this object

### Outputs Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

Options:

Description:Set the enabled status of the MooseObject.

• use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

Default:False

C++ Type:bool

Options:

Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

• control_tagsAdds user-defined labels for accessing object parameters via control logic.

C++ Type:std::vector

Options:

Description:Adds user-defined labels for accessing object parameters via control logic.

• seed0The seed for the master random number generator

Default:0

C++ Type:unsigned int

Options:

Description:The seed for the master random number generator

• implicitTrueDetermines whether this object is calculated using an implicit or explicit form

Default:True

C++ Type:bool

Options:

Description:Determines whether this object is calculated using an implicit or explicit form

• constant_onNONEWhen ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

Default:NONE

C++ Type:MooseEnum

Options:NONE ELEMENT SUBDOMAIN

Description:When ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped