# Compute Interface Stress

Stress in the plane of an interface defined by the gradient of an order parameter

## Description

The resulting stress tensor has the property of having one Eigenvector in the direction of the order parameter gradient, with an Eigenvalue of zero, and two Eigenvectors perpendicular to that direction, with an Eigenvalue , where the scalar (stress) is a supplied parameter and (v) is a given order parameter. (1)

Then two more linearly independent vectors and are generated by determining the component of with the largest magnitude. and are then set to unit vectors from the set (2) such that (3) where the operator represents integer modulo. The basis is then orthonormalized using the modified Gram-Schmidt procedure, holding constant. We construct two matrices (4) and set the stress tensor to (5) which is a basis transformation from the Eigenvector basis into the cartesian basis. The factor causes the integral over the stress tensor across the interface to evaluate the same value, regardless of interfacial width (provided the order parameter range is well defined - commonly 0 and 1 on the two sides of the interface).

## Example Input File Syntax

[./interface]
type = ComputeInterfaceStress
v = eta
stress = 3.0
[../]
(modules/tensor_mechanics/test/tests/interface_stress/test.i)

## Input Parameters

• stressInterfacial planar stress magnitude (one value to apply to all order parameters or one value per order parameter listed in 'v')

C++ Type:std::vector

Options:

Description:Interfacial planar stress magnitude (one value to apply to all order parameters or one value per order parameter listed in 'v')

### Required Parameters

• 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.

• op_range1 Range over which order parameters change across an interface. By default order parameters are assumed to vary from 0 to 1

Default:1

C++ Type:std::vector

Options:

Description:Range over which order parameters change across an interface. By default order parameters are assumed to vary from 0 to 1

• planar_stress_nameextra_stressMaterial property name for the interfacial planar stress

Default:extra_stress

C++ Type:MaterialPropertyName

Options:

Description:Material property name for the interfacial planar stress

• vOrder parameters that define the interface. The interface is the region where the gradient of this order parameter is non-zero.

C++ Type:std::vector

Options:

Description:Order parameters that define the interface. The interface is the region where the gradient of this order parameter is non-zero.

• 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

• 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

### Optional 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

• 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