# Uvar element = document.getElementById("moose-equation-74d690e6-6d96-4a9f-8bd6-bce607842e36");katex.render("_3", element, {displayMode:false,throwOnError:false});Sivar element = document.getElementById("moose-equation-c1a1a01d-e197-4b07-9427-63e2fa377998");katex.render("_5", element, {displayMode:false,throwOnError:false});UN Fuel Thermal Expansion Eigenstrain

Calculates eigenstrain due to isotropic thermal expansion in U3Si5UN fuel using a correlation from the IFR Handbook

## Description

The thermal expansion of U3Si5UN fuel is modeled as U3Si5UNThermalExpansionEigenstrain with the correlation from IFR Property Evaluation Working Group (1988): (1) where is the temperature (K) and is the stress free temperature thermal expansion strain. The coefficients through are given in Table 1.

Table 1: Values of Coefficients

Thermal Expansion CoefficientCoefficient Value
3.80635E-11
-7.55591E-08
5.75170E-05
-1.19940E-02

## Example Input Syntax


[./thermal_expansion]
type = U3Si5UNThermalExpansionEigenstrain
temperature = temperature
stress_free_temperature = 300.0
eigenstrain_name = thermal_expansion
[../]
(test/tests/tensor_mechanics/u3si2un_eigenstrains/thermal_expansion.i)

The eigenstrain_name parameter value must also be set for the strain calculator, and an example parameter setting in the Tensor Mechanics Master Action is shown below:


[Modules]
[./TensorMechanics]
[./Master]
[./all]
strain = SMALL
incremental = true
eigenstrain_names = 'thermal_expansion'
generate_output = 'strain_yy strain_xx strain_zz'
[../]
[../]
[../]
[]
(test/tests/tensor_mechanics/u3si2un_eigenstrains/thermal_expansion.i)

## Input Parameters

• stress_free_temperatureStress free temperature (does not produce thermal expansion stress) for thermal eigenstrain calculation; if you are unsure of what value to use for the stress_free_temperature, set this parameter equal to to the initial temperature for the fuel

C++ Type:double

Description:Stress free temperature (does not produce thermal expansion stress) for thermal eigenstrain calculation; if you are unsure of what value to use for the stress_free_temperature, set this parameter equal to to the initial temperature for the fuel

• temperatureCoupled temperature

C++ Type:std::vector

Description:Coupled temperature

• 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

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.

### Required Parameters

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

C++ Type:std::vector

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

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.

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

C++ Type:std::vector

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

• 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

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

### Optional Parameters

• enableTrueSet the enabled status of the MooseObject.

Default:True

C++ Type:bool

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

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

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

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

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

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

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

C++ Type:std::vector

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

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

## References

1. Compiled by: IFR Property Evaluation Working Group. Metallic fuels handbook. Argonne National Laboratory, June 1988.[BibTeX]