ComputeEigenstrain computes an Eigenstrain that results from an initial stress. More...

#include <ComputeEigenstrainFromInitialStress.h>

Inheritance diagram for ComputeEigenstrainFromInitialStress:

Public Member Functions
	ComputeEigenstrainFromInitialStress (const InputParameters &parameters)

Protected Member Functions
virtual void	computeQpEigenstrain () override
	Compute the eigenstrain and store in _eigenstrain. More...

virtual void	initQpStatefulProperties ()

virtual void	computeQpProperties ()

Real	computeVolumetricStrainComponent (const Real volumetric_strain) const
	Helper function for models that compute the eigenstrain based on a volumetric strain. More...

Protected Attributes
const std::string	_base_name
	base_name for elasticity tensor to use to convert stress to strain More...

const MaterialProperty< RankFourTensor > &	_elasticity_tensor
	elasticity tensor used to convert stress to strain More...

const MaterialProperty< RankTwoTensor > &	_eigenstrain_old
	Stores the total eigenstrain in the previous step. More...

std::vector< Function * >	_initial_stress_fcn
	initial stress components More...

std::string	_eigenstrain_name
	Material property name for the eigenstrain tensor. More...

MaterialProperty< RankTwoTensor > &	_eigenstrain
	Stores the current total eigenstrain. More...

bool &	_step_zero
	Restartable data to check for the zeroth and first time steps for thermal calculations. More...

Detailed Description

ComputeEigenstrain computes an Eigenstrain that results from an initial stress.

Definition at line 24 of file ComputeEigenstrainFromInitialStress.h.

Constructor & Destructor Documentation

◆ ComputeEigenstrainFromInitialStress()

ComputeEigenstrainFromInitialStress::ComputeEigenstrainFromInitialStress ( const InputParameters & parameters )

Definition at line 36 of file ComputeEigenstrainFromInitialStress.C.

   : ComputeEigenstrainBase(parameters),
     _base_name(isParamValid("base_name") ? getParam<std::string>("base_name") + "_" : ""),
     _elasticity_tensor(getMaterialPropertyByName<RankFourTensor>(_base_name + "elasticity_tensor")),
     _eigenstrain_old(getMaterialPropertyOld<RankTwoTensor>(_eigenstrain_name))
 {
   const std::vector<FunctionName> & fcn_names(
       getParam<std::vector<FunctionName>>("initial_stress"));
   const unsigned num = fcn_names.size();
 
   if (num != LIBMESH_DIM * LIBMESH_DIM)
     mooseError("ComputeEigenstrainFromInitialStress: ",
                LIBMESH_DIM * LIBMESH_DIM,
                " initial stress functions must be provided.  You supplied ",
                num,
                "\n");
 
   _initial_stress_fcn.resize(num);
   for (unsigned i = 0; i < num; ++i)
     _initial_stress_fcn[i] = &getFunctionByName(fcn_names[i]);
 }

Member Function Documentation

◆ computeQpEigenstrain()

void ComputeEigenstrainFromInitialStress::computeQpEigenstrain ( )

overrideprotectedvirtual

Compute the eigenstrain and store in _eigenstrain.

Implements ComputeEigenstrainBase.

Definition at line 60 of file ComputeEigenstrainFromInitialStress.C.

 {
   if (_t_step == 1)
   {
     RankTwoTensor initial_stress;
     for (unsigned i = 0; i < LIBMESH_DIM; ++i)
       for (unsigned j = 0; j < LIBMESH_DIM; ++j)
         initial_stress(i, j) = _initial_stress_fcn[i * LIBMESH_DIM + j]->value(_t, _q_point[_qp]);
 
     _eigenstrain[_qp] = -_elasticity_tensor[_qp].invSymm() * initial_stress;
   }
   else
     _eigenstrain[_qp] = _eigenstrain_old[_qp];
 }

◆ computeQpProperties()

void ComputeEigenstrainBase::computeQpProperties ( )

protectedvirtualinherited

Definition at line 53 of file ComputeEigenstrainBase.C.

 {
   if (_t_step >= 1)
     _step_zero = false;
 
   // Skip the eigenstrain calculation in step zero because no solution is computed during
   // the zeroth step, hence computing the eigenstrain in the zeroth step would result in
   // an incorrect calculation of mechanical_strain, which is stateful.
   if (!_step_zero)
     computeQpEigenstrain();
 }

◆ computeVolumetricStrainComponent()

Real ComputeEigenstrainBase::computeVolumetricStrainComponent ( const Real volumetric_strain ) const

protectedinherited

Helper function for models that compute the eigenstrain based on a volumetric strain.

This function computes the diagonal components of the eigenstrain tensor as logarithmic strains.

Parameters

volumetric_strain The current volumetric strain to be applied

Returns: Current strain in one direction due to volumetric strain, expressed as a logarithmic strain

Definition at line 66 of file ComputeEigenstrainBase.C.

 {
   // The engineering strain in a given direction is:
   // epsilon_eng = cbrt(volumetric_strain + 1.0) - 1.0
   //
   // We need to provide this as a logarithmic strain to be consistent with the strain measure
   // used for finite strain:
   // epsilon_log = log(1.0 + epsilon_eng)
   //
   // This can be simplified down to a more direct form:
   // epsilon_log = log(cbrt(volumetric_strain + 1.0))
   // or:
   // epsilon_log = (1/3) log(volumetric_strain + 1.0)
 
   return std::log(volumetric_strain + 1.0) / 3.0;
 }

◆ initQpStatefulProperties()

void ComputeEigenstrainBase::initQpStatefulProperties ( )

protectedvirtualinherited

Reimplemented in ComputeReducedOrderEigenstrain.

Definition at line 45 of file ComputeEigenstrainBase.C.

 {
   // This property can be promoted to be stateful by other models that use it,
   // so it needs to be initalized.
   _eigenstrain[_qp].zero();
 }