This class is an implementation of a generalized Kelvin-Voigt model with constant mechanical properties. More...

#include <GeneralizedKelvinVoigtModel.h>

Inheritance diagram for GeneralizedKelvinVoigtModel:

Public Types
enum	IntegrationRule { IntegrationRule::BackwardEuler, IntegrationRule::MidPoint, IntegrationRule::Newmark, IntegrationRule::Zienkiewicz }
	Determines how theta is calculated for the time-integration system. More...

Public Member Functions
	GeneralizedKelvinVoigtModel (const InputParameters &parameters)

void	recomputeQpApparentProperties (unsigned int qp)
	Compute the apparent properties at a quadrature point. More...

bool	hasGuarantee (const MaterialPropertyName &prop_name, Guarantee guarantee)

Static Public Member Functions
static InputParameters	validParams ()

Protected Member Functions
virtual void	computeQpViscoelasticProperties ()
	This method assigns the mechanical properties of each spring and dashpot in the system. More...

virtual void	computeQpViscoelasticPropertiesInv ()
	This method computes the inverse elasticity tensor of each spring in the system (if required). More...

virtual void	computeQpApparentElasticityTensors () final
	This method computes the apparent elasticity tensor used in the internal time-stepping scheme. More...

virtual void	computeQpApparentCreepStrain () final
	This method computes the apparent creep strain corresponding to the current viscous_strain of each dashpot. More...

virtual void	updateQpViscousStrains () final
	Update the internal viscous strains at a quadrature point. More...

virtual void	initQpStatefulProperties () override

virtual void	computeQpElasticityTensor () final
	Inherited from ComputeElasticityTensorBase. More...

void	declareViscoelasticProperties ()
	Declare all necessary MaterialProperties for the model. More...

Real	computeTheta (Real dt, Real viscosity) const
	Provides theta as a function of the time step and a viscosity. More...

virtual void	computeQpProperties ()

void	issueGuarantee (const MaterialPropertyName &prop_name, Guarantee guarantee)

void	revokeGuarantee (const MaterialPropertyName &prop_name, Guarantee guarantee)

Protected Attributes
RankFourTensor	_C0
	The elasticity tensor associated with the first spring. More...

std::vector< RankFourTensor >	_Ci
	The elasticity tensor of each subsequent spring. More...

std::vector< Real >	_eta_i
	The viscosity of each dashpot. More...

RankFourTensor	_S0
	The inverse of the elasticity tensor of the first spring. More...

std::vector< RankFourTensor >	_Si
	The inverse of each subsequent spring elasticity tensor. More...

IntegrationRule	_integration_rule
	Determines how theta is computed. More...

Real	_theta
	User-defined value for theta. More...

MaterialProperty< RankFourTensor > &	_apparent_elasticity_tensor
	Apparent elasticity tensor. This is NOT the elasticity tensor of the material. More...

MaterialProperty< RankFourTensor > &	_apparent_elasticity_tensor_inv
	Inverse of the apparent elasticity tensor. More...

MaterialProperty< RankFourTensor > &	_elasticity_tensor_inv
	Instantaneous elasticity tensor. This IS the real elasticity tensor of the material. More...

bool	_need_viscoelastic_properties_inverse
	If active, indicates that we need to call computeQpViscoelasticPropertiesInv() More...

bool	_has_longterm_dashpot
	Indicates if the spring-dashpot assembly has a single dashpot not associated with a spring. More...

unsigned int	_components
	This is the number of internal variables required by the model. More...

const MaterialProperty< RankTwoTensor > &	_elastic_strain_old
	previous value of the elastic strain for update purposes More...

const MaterialProperty< RankTwoTensor > &	_creep_strain_old
	Previous value of the true creep strain for update purposes. More...

bool	_has_driving_eigenstrain
	Indicates if the model is only driven by the stress, or also by an additional eigenstrain. More...

std::string	_driving_eigenstrain_name
	Name of the eigenstrain that drives the additional creep strain. More...

bool	_force_recompute_properties
	If activated, the time-stepping scheme will be re-initialized at each step of the solver. More...

bool &	_step_zero
	checks whether we are at the first time step More...

const std::string	_base_name

std::string	_elasticity_tensor_name

MaterialProperty< RankFourTensor > &	_elasticity_tensor

MaterialProperty< Real > &	_effective_stiffness

const Function *const	_prefactor_function
	prefactor function to multiply the elasticity tensor with More...


const MaterialProperty< RankFourTensor > &	_first_elasticity_tensor_old
	old material properties required for the update of the viscoelastic strain More...

const MaterialProperty< RankFourTensor > &	_first_elasticity_tensor_inv_old


MaterialProperty< RankFourTensor > &	_first_elasticity_tensor
	Elasticity tensor of a stand-alone elastic spring in the chain. More...

MaterialProperty< RankFourTensor > *	_first_elasticity_tensor_inv


std::vector< MaterialProperty< RankFourTensor > * >	_springs_elasticity_tensors
	List of elasticity tensor of each subsequent spring in the chain. More...

std::vector< MaterialProperty< RankFourTensor > * >	_springs_elasticity_tensors_inv

std::vector< const MaterialProperty< RankFourTensor > * >	_springs_elasticity_tensors_inv_old


std::vector< MaterialProperty< Real > * >	_dashpot_viscosities
	List of viscosities of each subsequent dashpot in the chain. More...

std::vector< const MaterialProperty< Real > * >	_dashpot_viscosities_old


std::vector< MaterialProperty< RankTwoTensor > * >	_viscous_strains

std::vector< const MaterialProperty< RankTwoTensor > * >	_viscous_strains_old


MaterialProperty< RankTwoTensor > &	_apparent_creep_strain
	The apparent creep strain resulting from the internal viscous strains. More...

const MaterialProperty< RankTwoTensor > &	_apparent_creep_strain_old


const MaterialProperty< RankTwoTensor > *	_driving_eigenstrain
	Pointer to the value of the driving eigenstrain. More...

const MaterialProperty< RankTwoTensor > *	_driving_eigenstrain_old

Private Attributes
std::map< MaterialPropertyName, std::set< Guarantee > >	_guarantees

Detailed Description

This class is an implementation of a generalized Kelvin-Voigt model with constant mechanical properties.

It consists of an arbitrary number of Kelvin-Voigt units associated in series with a single spring, and an optional dashpot (this could represent a Burgers model, for example).

Definition at line 25 of file GeneralizedKelvinVoigtModel.h.

Member Enumeration Documentation

◆ IntegrationRule

enum LinearViscoelasticityBase::IntegrationRule

stronginherited

Determines how theta is calculated for the time-integration system.

Enumerator
BackwardEuler	theta = 1
MidPoint	theta = 0.5
Newmark	theta defined by the user
Zienkiewicz	theta automatically adjusted as a function of the time step and the viscosity

Definition at line 87 of file LinearViscoelasticityBase.h.

   {
     BackwardEuler,
     MidPoint,
     Newmark,
     Zienkiewicz,
   };

Constructor & Destructor Documentation

◆ GeneralizedKelvinVoigtModel()

GeneralizedKelvinVoigtModel::GeneralizedKelvinVoigtModel ( const InputParameters & parameters )

Definition at line 36 of file GeneralizedKelvinVoigtModel.C.

   : GeneralizedKelvinVoigtBase(parameters),
     _Ci(getParam<std::vector<Real>>("creep_modulus").size()),
     _eta_i(getParam<std::vector<Real>>("creep_viscosity")),
     _Si(getParam<std::vector<Real>>("creep_modulus").size())
 {
   Real young_modulus = getParam<Real>("young_modulus");
   Real poisson_ratio = getParam<Real>("poisson_ratio");
  
   _C0.fillFromInputVector({young_modulus, poisson_ratio}, RankFourTensor::symmetric_isotropic_E_nu);
   _S0 = _C0.invSymm();
  
   std::vector<Real> creep_modulus = getParam<std::vector<Real>>("creep_modulus");
   std::vector<Real> creep_ratio;
   if (isParamValid("creep_ratio"))
     creep_ratio = getParam<std::vector<Real>>("creep_ratio");
   else
     creep_ratio.resize(_Ci.size(), poisson_ratio);
  
   if (creep_modulus.size() != _Ci.size())
     mooseError("incompatible number of creep moduli and viscosities");
   if (creep_ratio.size() != _Ci.size())
     mooseError("incompatible number of creep ratios and viscosities");
   if (!(_Ci.size() == _eta_i.size() || _Ci.size() + 1 == _eta_i.size()))
     mooseError("incompatible number of creep ratios and viscosities");
  
   for (unsigned int i = 0; i < _Ci.size(); ++i)
   {
     _Ci[i].fillFromInputVector({creep_modulus[i], creep_ratio[i]},
                                RankFourTensor::symmetric_isotropic_E_nu);
     _Si[i] = _Ci[i].invSymm();
   }
  
   for (unsigned int i = 0; i < _eta_i.size(); ++i)
   {
     if (_eta_i[i] < 0 || MooseUtils::absoluteFuzzyEqual(_eta_i[i], 0.0))
       mooseError("material viscosity must be strictly > 0");
   }
  
   _components = _eta_i.size();
   _has_longterm_dashpot = (_eta_i.size() == _Ci.size() + 1);
  
   issueGuarantee(_elasticity_tensor_name, Guarantee::ISOTROPIC);
   declareViscoelasticProperties();
 }

Member Function Documentation

◆ computeQpApparentCreepStrain()

void GeneralizedKelvinVoigtBase::computeQpApparentCreepStrain ( )

finalprotectedvirtualinherited

This method computes the apparent creep strain corresponding to the current viscous_strain of each dashpot.

It must be called after the apparent elasticity tensors have been calculated.

This method is purely virtual. Inherited classes must override it.

This method is related to the internal time-stepping scheme. It should only be overwritten by classes that inherit directly from LinearViscoelasticityBase, and that represent a different spring-dashpot assembly. See GeneralizedKelvinVoigtBase for example.

Implements LinearViscoelasticityBase.

Definition at line 88 of file GeneralizedKelvinVoigtBase.C.

 {
   _apparent_creep_strain[_qp].zero();
  
   for (unsigned int i = 0; i < _springs_elasticity_tensors.size(); ++i)
   {
     Real theta_i = computeTheta(_dt, (*_dashpot_viscosities[i])[_qp]);
     Real gamma = (*_dashpot_viscosities[i])[_qp] / (_dt * theta_i);
     _apparent_creep_strain[_qp] += (*_viscous_strains[i])[_qp] * (gamma / (1. + gamma));
   }
  
   if (_has_longterm_dashpot)
     _apparent_creep_strain[_qp] += (*_viscous_strains.back())[_qp];
  
   if (_has_driving_eigenstrain)
   {
     RankFourTensor cumulated_driving_tensor;
     cumulated_driving_tensor.zero();
     for (unsigned int i = 0; i < _springs_elasticity_tensors.size(); ++i)
     {
       double theta_i = computeTheta(_dt, (*_dashpot_viscosities[i])[_qp]);
       double gamma = (*_dashpot_viscosities[i])[_qp] / (_dt * theta_i);
       cumulated_driving_tensor += (*_springs_elasticity_tensors_inv[i])[_qp] / (1. + gamma);
     }
  
     _apparent_creep_strain[_qp] +=
         (_elasticity_tensor[_qp] * cumulated_driving_tensor) * (*_driving_eigenstrain)[_qp];
  
     if (_has_longterm_dashpot)
     {
       double theta_i = computeTheta(_dt, (*_dashpot_viscosities.back())[_qp]);
       double gamma = (*_dashpot_viscosities.back())[_qp] / (_dt * theta_i);
       _apparent_creep_strain[_qp] += (*_driving_eigenstrain)[_qp] / gamma;
     }
   }
 }

◆ computeQpApparentElasticityTensors()

void GeneralizedKelvinVoigtBase::computeQpApparentElasticityTensors ( )

finalprotectedvirtualinherited

This method computes the apparent elasticity tensor used in the internal time-stepping scheme.

It is called after the mechanical properties have been set, and before the apparent creep strains are calculated.

This method is also responsible for calculating the instantaneous elasticity tensor, and the inverse of both the apparent and instantaneous elasticity tensors.

This method is purely virtual. Inherited classes must override it.

This method is related to the internal time-stepping scheme. It should only be overwritten by classes that inherit directly from LinearViscoelasticityBase, and that represent a different spring-dashpot assembly. See GeneralizedKelvinVoigtBase for example.

Implements LinearViscoelasticityBase.

Definition at line 63 of file GeneralizedKelvinVoigtBase.C.

 {
   _elasticity_tensor[_qp] = _first_elasticity_tensor[_qp];
   _elasticity_tensor_inv[_qp] = (*_first_elasticity_tensor_inv)[_qp];
   _apparent_elasticity_tensor_inv[_qp] = (*_first_elasticity_tensor_inv)[_qp];
  
   for (unsigned int i = 0; i < _springs_elasticity_tensors.size(); ++i)
   {
     Real theta_i = computeTheta(_dt, (*_dashpot_viscosities[i])[_qp]);
     Real gamma = (*_dashpot_viscosities[i])[_qp] / (_dt * theta_i);
     _apparent_elasticity_tensor_inv[_qp] +=
         (*_springs_elasticity_tensors_inv[i])[_qp] / (1. + gamma);
   }
  
   if (_has_longterm_dashpot)
   {
     Real theta_i = computeTheta(_dt, (*_dashpot_viscosities.back())[_qp]);
     Real gamma = (*_dashpot_viscosities.back())[_qp] / (_dt * theta_i);
     _apparent_elasticity_tensor_inv[_qp] += (*_first_elasticity_tensor_inv)[_qp] / gamma;
   }
  
   _apparent_elasticity_tensor[_qp] = _apparent_elasticity_tensor_inv[_qp].invSymm();
 }

◆ computeQpElasticityTensor()

void LinearViscoelasticityBase::computeQpElasticityTensor ( )

finalprotectedvirtualinherited

Inherited from ComputeElasticityTensorBase.

Implements ComputeElasticityTensorBase.

Definition at line 192 of file LinearViscoelasticityBase.C.

 {
   if (_force_recompute_properties)
     recomputeQpApparentProperties(_qp);
 }

◆ computeQpProperties()

void ComputeElasticityTensorBase::computeQpProperties ( )

protectedvirtualinherited

Definition at line 43 of file ComputeElasticityTensorBase.C.

 {
   _effective_stiffness[_qp] = 0; // Currently overriden by ComputeIsotropicElasticityTensor
   computeQpElasticityTensor();
  
   // Multiply by prefactor
   if (_prefactor_function)
   {
     _elasticity_tensor[_qp] *= _prefactor_function->value(_t, _q_point[_qp]);
     _effective_stiffness[_qp] *= std::sqrt(_prefactor_function->value(_t, _q_point[_qp]));
   }
 }

◆ computeQpViscoelasticProperties()

void GeneralizedKelvinVoigtModel::computeQpViscoelasticProperties ( )

protectedvirtual

This method assigns the mechanical properties of each spring and dashpot in the system.

This method is purely virtual. Inherited classes must override it.

This method is related to the storage of the mechanical properties of each spring and dashpot in the system, and not the internal time-stepping procedure. Only end-user classes should override it. See GeneralizedKelvinVoigModel for example.

Implements LinearViscoelasticityBase.

Definition at line 83 of file GeneralizedKelvinVoigtModel.C.

 {
   _first_elasticity_tensor[_qp] = _C0;
  
   for (unsigned int i = 0; i < _Ci.size(); ++i)
     (*_springs_elasticity_tensors[i])[_qp] = _Ci[i];
  
   for (unsigned int i = 0; i < _eta_i.size(); ++i)
     (*_dashpot_viscosities[i])[_qp] = _eta_i[i];
 }

◆ computeQpViscoelasticPropertiesInv()

void GeneralizedKelvinVoigtModel::computeQpViscoelasticPropertiesInv ( )

protectedvirtual

This method computes the inverse elasticity tensor of each spring in the system (if required).

This method is virtual. Its default behavior computes the inverse of each tensor. It must be inherited only if there is a faster way to compute this inverse (for example, if they are known).

This method is related to the storage of the mechanical properties of each spring and dashpot in the system, and not the internal time-stepping procedure. Only end-user classes should override it. See GeneralizedKelvinVoigtModel for example.

Reimplemented from LinearViscoelasticityBase.

Definition at line 95 of file GeneralizedKelvinVoigtModel.C.

 {
   (*_first_elasticity_tensor_inv)[_qp] = _S0;
  
   for (unsigned int i = 0; i < _Si.size(); ++i)
     (*_springs_elasticity_tensors_inv[i])[_qp] = _Si[i];
 }

◆ computeTheta()

Real LinearViscoelasticityBase::computeTheta	(	Real	dt,
		Real	viscosity
	)		const

protectedinherited

Provides theta as a function of the time step and a viscosity.

Definition at line 216 of file LinearViscoelasticityBase.C.

 {
   if (MooseUtils::absoluteFuzzyEqual(dt, 0.0))
     mooseError("linear viscoelasticity cannot be integrated over a dt of ", dt);
  
   switch (_integration_rule)
   {
     case IntegrationRule::BackwardEuler:
       return 1.;
     case IntegrationRule::MidPoint:
       return 0.5;
     case IntegrationRule::Newmark:
       return _theta;
     case IntegrationRule::Zienkiewicz:
       return 1. / (1. - std::exp(-dt / viscosity)) - viscosity / dt;
     default:
       return 1.;
   }
   return 1.;
 }

Referenced by GeneralizedKelvinVoigtBase::computeQpApparentCreepStrain(), GeneralizedMaxwellBase::computeQpApparentCreepStrain(), GeneralizedKelvinVoigtBase::computeQpApparentElasticityTensors(), GeneralizedMaxwellBase::computeQpApparentElasticityTensors(), GeneralizedKelvinVoigtBase::updateQpViscousStrains(), and GeneralizedMaxwellBase::updateQpViscousStrains().

◆ declareViscoelasticProperties()

void LinearViscoelasticityBase::declareViscoelasticProperties ( )

protectedinherited

Declare all necessary MaterialProperties for the model.

This method must be called once at the end of the constructor of a final inherited class, after _components has been set. See GeneralizedKelvinVoigtModel or GeneralizedMaxwell model for example.

Definition at line 102 of file LinearViscoelasticityBase.C.

 {
   for (unsigned int i = 0; i < _components; ++i)
   {
     std::string ith = Moose::stringify(i + 1);
  
     if (!_has_longterm_dashpot || (_components > 0 && i < _components - 1))
     {
       _springs_elasticity_tensors.push_back(
           &declareProperty<RankFourTensor>(_base_name + "spring_elasticity_tensor_" + ith));
       getMaterialPropertyOld<RankFourTensor>(_base_name + "spring_elasticity_tensor_" + ith);
     }
  
     _dashpot_viscosities.push_back(&declareProperty<Real>(_base_name + "dashpot_viscosity_" + ith));
     _dashpot_viscosities_old.push_back(
         &getMaterialPropertyOld<Real>(_base_name + "dashpot_viscosity_" + ith));
  
     _viscous_strains.push_back(
         &declareProperty<RankTwoTensor>(_base_name + "viscous_strain_" + ith));
     _viscous_strains_old.push_back(
         &getMaterialPropertyOld<RankTwoTensor>(_base_name + "viscous_strain_" + ith));
  
     if (_need_viscoelastic_properties_inverse)
     {
       _springs_elasticity_tensors_inv.push_back(&declareProperty<RankFourTensor>(
           _base_name + "spring_elasticity_tensor_" + ith + "_inv"));
       _springs_elasticity_tensors_inv_old.push_back(&getMaterialPropertyOld<RankFourTensor>(
           _base_name + "spring_elasticity_tensor_" + ith + "_inv"));
     }
   }
 }

Referenced by GeneralizedKelvinVoigtModel(), and GeneralizedMaxwellModel::GeneralizedMaxwellModel().

◆ hasGuarantee()

bool GuaranteeProvider::hasGuarantee	(	const MaterialPropertyName &	prop_name,
		Guarantee	guarantee
	)

inherited

Definition at line 16 of file GuaranteeProvider.C.

 {
   auto it = _guarantees.find(prop_name);
   if (it == _guarantees.end())
     return false;
  
   auto it2 = it->second.find(guarantee);
   return it2 != it->second.end();
 }

◆ initQpStatefulProperties()

void LinearViscoelasticityBase::initQpStatefulProperties ( )

overrideprotectedvirtualinherited

Definition at line 135 of file LinearViscoelasticityBase.C.

 {
   if (_components != _viscous_strains.size())
     mooseError(
         "inconsistent numbers of dashpots and viscous strains in LinearViscoelasticityBase;"
         " Make sure declareViscoelasticProperties has been called in the viscoelastic model");
  
   _apparent_creep_strain[_qp].zero();
   _apparent_elasticity_tensor[_qp].zero();
   _apparent_elasticity_tensor_inv[_qp].zero();
   _elasticity_tensor_inv[_qp].zero();
   _first_elasticity_tensor[_qp].zero();
   if (_need_viscoelastic_properties_inverse)
     (*_first_elasticity_tensor_inv)[_qp].zero();
  
   for (unsigned int i = 0; i < _components; ++i)
   {
     if (!_has_longterm_dashpot || (_components > 0 && i < _components - 1))
     {
       (*_springs_elasticity_tensors[i])[_qp].zero();
       if (_need_viscoelastic_properties_inverse)
         (*_springs_elasticity_tensors_inv[i])[_qp].zero();
     }
  
     (*_dashpot_viscosities[i])[_qp] = 0.0;
     (*_viscous_strains[i])[_qp].zero();
   }
 }

◆ issueGuarantee()

void GuaranteeProvider::issueGuarantee	(	const MaterialPropertyName &	prop_name,
		Guarantee	guarantee
	)

protectedinherited

Definition at line 27 of file GuaranteeProvider.C.

 {
   // intentional insertion
   _guarantees[prop_name].insert(guarantee);
 }

Referenced by ADComputeVariableIsotropicElasticityTensor< compute_stage >::ADComputeVariableIsotropicElasticityTensor(), ComputeCosseratElasticityTensor::ComputeCosseratElasticityTensor(), ComputeElasticityTensor::ComputeElasticityTensor(), ComputeIsotropicElasticityTensor::ComputeIsotropicElasticityTensor(), ComputeLayeredCosseratElasticityTensor::ComputeLayeredCosseratElasticityTensor(), ComputeVariableIsotropicElasticityTensor::ComputeVariableIsotropicElasticityTensor(), GeneralizedKelvinVoigtModel(), and GeneralizedMaxwellModel::GeneralizedMaxwellModel().

◆ recomputeQpApparentProperties()

void LinearViscoelasticityBase::recomputeQpApparentProperties ( unsigned int qp )

inherited

Compute the apparent properties at a quadrature point.

This initializes the internal time-stepping scheme, and must be called at the beginning of the time step.

This method is called by LinearViscoelasticityManager.

Definition at line 165 of file LinearViscoelasticityBase.C.

 {
   unsigned int qp_prev = _qp;
   _qp = qp;
  
   if (_t_step >= 1)
     _step_zero = false;
  
   // 1. we get the viscoelastic properties and their inverse if needed
   computeQpViscoelasticProperties();
   if (_need_viscoelastic_properties_inverse)
     computeQpViscoelasticPropertiesInv();
  
   // 2. we update the internal viscous strains from the previous time step
   updateQpViscousStrains();
  
   // 3. we compute the apparent elasticity tensor
   computeQpApparentElasticityTensors();
  
   // 4. we transform the internal viscous strains in an apparent creep strain
   if (!_step_zero)
     computeQpApparentCreepStrain();
  
   _qp = qp_prev;
 }

Referenced by LinearViscoelasticityBase::computeQpElasticityTensor().

◆ revokeGuarantee()

void GuaranteeProvider::revokeGuarantee	(	const MaterialPropertyName &	prop_name,
		Guarantee	guarantee
	)

protectedinherited

Definition at line 34 of file GuaranteeProvider.C.

 {
   auto it = _guarantees.find(prop_name);
   if (it != _guarantees.end())
     it->second.erase(guarantee);
 }

Referenced by ComputeElasticityTensorCP::ComputeElasticityTensorCP().

◆ updateQpViscousStrains()

void GeneralizedKelvinVoigtBase::updateQpViscousStrains ( )

finalprotectedvirtualinherited

Update the internal viscous strains at a quadrature point.

Calling this method is required at the end of each time step to update the internal time-stepping scheme correctly.

This method is pure virtual. Inherited classes must override it.

This method is related to the internal time-stepping scheme. It should only be overwritten by classes that inherit directly from LinearViscoelasticityBase, and that represent a different spring-dashpot assembly. See GeneralizedKelvinVoigtBase or GeneralizedMaxwellBase for example.

Implements LinearViscoelasticityBase.

Definition at line 33 of file GeneralizedKelvinVoigtBase.C.

 {
   if (_t_step <= 1)
     return;
  
   RankTwoTensor effective_stress = _first_elasticity_tensor_old[_qp] * _elastic_strain_old[_qp];
  
   if (_has_driving_eigenstrain)
     effective_stress += _first_elasticity_tensor_old[_qp] * (*_driving_eigenstrain_old)[_qp];
  
   for (unsigned int i = 0; i < _springs_elasticity_tensors.size(); ++i)
   {
     Real theta_i = computeTheta(_dt_old, (*_dashpot_viscosities_old[i])[_qp]);
     Real gamma = (*_dashpot_viscosities_old[i])[_qp] / (_dt_old * theta_i);
     (*_viscous_strains[i])[_qp] =
         ((*_springs_elasticity_tensors_inv_old[i])[_qp] * effective_stress) /
         (theta_i * (1. + gamma));
     (*_viscous_strains[i])[_qp] += (*_viscous_strains_old[i])[_qp] *
                                    (gamma / (theta_i * (1. + gamma)) - (1. - theta_i) / theta_i);
   }
  
   if (_has_longterm_dashpot)
   {
     (*_viscous_strains.back())[_qp] = (_first_elasticity_tensor_inv_old[_qp] * effective_stress) *
                                       (_dt_old / (*_dashpot_viscosities_old.back())[_qp]);
     (*_viscous_strains.back())[_qp] += (*_viscous_strains_old.back())[_qp];
   }
 }

◆ validParams()

InputParameters GeneralizedKelvinVoigtModel::validParams ( )

static

Definition at line 17 of file GeneralizedKelvinVoigtModel.C.

 {
   InputParameters params = GeneralizedKelvinVoigtBase::validParams();
   params.addClassDescription(
       "Generalized Kelvin-Voigt model composed of a serial assembly of unit Kelvin-Voigt modules");
   params.addRequiredParam<Real>("young_modulus", "initial elastic modulus of the material");
   params.addRequiredParam<Real>("poisson_ratio", "initial poisson ratio of the material");
   params.addRequiredParam<std::vector<Real>>(
       "creep_modulus", "list of the elastic moduli of the different springs in the material");
   params.addRequiredParam<std::vector<Real>>(
       "creep_viscosity",
       "list of the characteristic times of the different dashpots in the material");
   params.addParam<std::vector<Real>>(
       "creep_ratio", "list of the poisson ratios of the different springs in the material");
   params.set<bool>("force_recompute_properties") = false;
   params.suppressParameter<bool>("force_recompute_properties");
   return params;
 }

Member Data Documentation

◆ _apparent_creep_strain

MaterialProperty<RankTwoTensor>& LinearViscoelasticityBase::_apparent_creep_strain

protectedinherited

The apparent creep strain resulting from the internal viscous strains.

Definition at line 241 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedKelvinVoigtBase::computeQpApparentCreepStrain(), GeneralizedMaxwellBase::computeQpApparentCreepStrain(), and LinearViscoelasticityBase::initQpStatefulProperties().

◆ _apparent_creep_strain_old

const MaterialProperty<RankTwoTensor>& LinearViscoelasticityBase::_apparent_creep_strain_old

protectedinherited

Definition at line 242 of file LinearViscoelasticityBase.h.

◆ _apparent_elasticity_tensor

MaterialProperty<RankFourTensor>& LinearViscoelasticityBase::_apparent_elasticity_tensor

protectedinherited

Apparent elasticity tensor. This is NOT the elasticity tensor of the material.

Definition at line 197 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedKelvinVoigtBase::computeQpApparentElasticityTensors(), GeneralizedMaxwellBase::computeQpApparentElasticityTensors(), and LinearViscoelasticityBase::initQpStatefulProperties().

◆ _apparent_elasticity_tensor_inv

MaterialProperty<RankFourTensor>& LinearViscoelasticityBase::_apparent_elasticity_tensor_inv

protectedinherited

Inverse of the apparent elasticity tensor.

Definition at line 199 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedMaxwellBase::computeQpApparentCreepStrain(), GeneralizedMaxwellBase::computeQpApparentElasticityTensors(), GeneralizedKelvinVoigtBase::computeQpApparentElasticityTensors(), and LinearViscoelasticityBase::initQpStatefulProperties().

◆ _base_name

const std::string ComputeElasticityTensorBase::_base_name

protectedinherited

Definition at line 37 of file ComputeElasticityTensorBase.h.

Referenced by LinearViscoelasticityBase::declareViscoelasticProperties(), and LinearViscoelasticityBase::LinearViscoelasticityBase().

◆ _C0

RankFourTensor GeneralizedKelvinVoigtModel::_C0

protected

The elasticity tensor associated with the first spring.

This is the true elasticity tensor of the material

Definition at line 40 of file GeneralizedKelvinVoigtModel.h.

Referenced by computeQpViscoelasticProperties(), and GeneralizedKelvinVoigtModel().

◆ _Ci

std::vector<RankFourTensor> GeneralizedKelvinVoigtModel::_Ci

protected

The elasticity tensor of each subsequent spring.

Definition at line 42 of file GeneralizedKelvinVoigtModel.h.

Referenced by computeQpViscoelasticProperties(), and GeneralizedKelvinVoigtModel().

◆ _components

unsigned int LinearViscoelasticityBase::_components

protectedinherited

This is the number of internal variables required by the model.

This must be set in the constructor of an inherited class. See GeneralizedKelvinVoigtModel for example.

Definition at line 214 of file LinearViscoelasticityBase.h.

Referenced by LinearViscoelasticityBase::declareViscoelasticProperties(), GeneralizedKelvinVoigtModel(), GeneralizedMaxwellModel::GeneralizedMaxwellModel(), and LinearViscoelasticityBase::initQpStatefulProperties().

◆ _creep_strain_old

const MaterialProperty<RankTwoTensor>& LinearViscoelasticityBase::_creep_strain_old

protectedinherited

Previous value of the true creep strain for update purposes.

This is calculated by a ComputeLinearViscoelasticStress or a LinearViscoelasticStressUpdate material.

Definition at line 252 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedMaxwellBase::updateQpViscousStrains().

◆ _dashpot_viscosities

std::vector<MaterialProperty<Real> *> LinearViscoelasticityBase::_dashpot_viscosities

protectedinherited

List of viscosities of each subsequent dashpot in the chain.

Definition at line 228 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedKelvinVoigtBase::computeQpApparentCreepStrain(), GeneralizedMaxwellBase::computeQpApparentCreepStrain(), GeneralizedKelvinVoigtBase::computeQpApparentElasticityTensors(), GeneralizedMaxwellBase::computeQpApparentElasticityTensors(), computeQpViscoelasticProperties(), GeneralizedMaxwellModel::computeQpViscoelasticProperties(), LinearViscoelasticityBase::declareViscoelasticProperties(), and LinearViscoelasticityBase::initQpStatefulProperties().

◆ _dashpot_viscosities_old

std::vector<const MaterialProperty<Real> *> LinearViscoelasticityBase::_dashpot_viscosities_old

protectedinherited

Definition at line 229 of file LinearViscoelasticityBase.h.

Referenced by LinearViscoelasticityBase::declareViscoelasticProperties(), GeneralizedMaxwellBase::updateQpViscousStrains(), and GeneralizedKelvinVoigtBase::updateQpViscousStrains().

◆ _driving_eigenstrain

const MaterialProperty<RankTwoTensor>* LinearViscoelasticityBase::_driving_eigenstrain

protectedinherited

Pointer to the value of the driving eigenstrain.

Definition at line 259 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedKelvinVoigtBase::computeQpApparentCreepStrain(), and GeneralizedMaxwellBase::computeQpApparentCreepStrain().

◆ _driving_eigenstrain_name

std::string LinearViscoelasticityBase::_driving_eigenstrain_name

protectedinherited

Name of the eigenstrain that drives the additional creep strain.

Definition at line 257 of file LinearViscoelasticityBase.h.

◆ _driving_eigenstrain_old

const MaterialProperty<RankTwoTensor>* LinearViscoelasticityBase::_driving_eigenstrain_old

protectedinherited

Definition at line 260 of file LinearViscoelasticityBase.h.

◆ _effective_stiffness

MaterialProperty<Real>& ComputeElasticityTensorBase::_effective_stiffness

protectedinherited

Definition at line 41 of file ComputeElasticityTensorBase.h.

Referenced by ComputeIsotropicElasticityTensor::computeQpElasticityTensor(), and ComputeElasticityTensorBase::computeQpProperties().

◆ _elastic_strain_old

const MaterialProperty<RankTwoTensor>& LinearViscoelasticityBase::_elastic_strain_old

protectedinherited

previous value of the elastic strain for update purposes

Definition at line 246 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedKelvinVoigtBase::updateQpViscousStrains(), and GeneralizedMaxwellBase::updateQpViscousStrains().

◆ _elasticity_tensor

MaterialProperty<RankFourTensor>& ComputeElasticityTensorBase::_elasticity_tensor

protectedinherited

Definition at line 40 of file ComputeElasticityTensorBase.h.

◆ _elasticity_tensor_inv

MaterialProperty<RankFourTensor>& LinearViscoelasticityBase::_elasticity_tensor_inv

protectedinherited

Instantaneous elasticity tensor. This IS the real elasticity tensor of the material.

Inverse of the instaneous elasticity tensor

Definition at line 204 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedKelvinVoigtBase::computeQpApparentElasticityTensors(), GeneralizedMaxwellBase::computeQpApparentElasticityTensors(), and LinearViscoelasticityBase::initQpStatefulProperties().

◆ _elasticity_tensor_name

std::string ComputeElasticityTensorBase::_elasticity_tensor_name

protectedinherited

Definition at line 38 of file ComputeElasticityTensorBase.h.

Referenced by ComputeCosseratElasticityTensor::ComputeCosseratElasticityTensor(), ComputeElasticityTensor::ComputeElasticityTensor(), ComputeElasticityTensorCP::ComputeElasticityTensorCP(), ComputeIsotropicElasticityTensor::ComputeIsotropicElasticityTensor(), ComputeLayeredCosseratElasticityTensor::ComputeLayeredCosseratElasticityTensor(), ComputePolycrystalElasticityTensor::ComputePolycrystalElasticityTensor(), ComputeVariableIsotropicElasticityTensor::ComputeVariableIsotropicElasticityTensor(), GeneralizedKelvinVoigtModel(), GeneralizedMaxwellModel::GeneralizedMaxwellModel(), ComputeVariableIsotropicElasticityTensor::initialSetup(), and LinearViscoelasticityBase::LinearViscoelasticityBase().

◆ _eta_i

std::vector<Real> GeneralizedKelvinVoigtModel::_eta_i

protected

The viscosity of each dashpot.

Definition at line 44 of file GeneralizedKelvinVoigtModel.h.

Referenced by computeQpViscoelasticProperties(), and GeneralizedKelvinVoigtModel().

◆ _first_elasticity_tensor

MaterialProperty<RankFourTensor>& LinearViscoelasticityBase::_first_elasticity_tensor

protectedinherited

Elasticity tensor of a stand-alone elastic spring in the chain.

Definition at line 217 of file LinearViscoelasticityBase.h.

Referenced by GeneralizedMaxwellBase::computeQpApparentCreepStrain(), GeneralizedKelvinVoigtBase::computeQpApparentElasticityTensors(), GeneralizedMaxwellBase::computeQpApparentElasticityTensors(), computeQpViscoelasticProperties(), GeneralizedMaxwellModel::computeQpViscoelasticProperties(), LinearViscoelasticityBase::computeQpViscoelasticPropertiesInv(), and LinearViscoelasticityBase::initQpStatefulProperties().

◆ _first_elasticity_tensor_inv

MaterialProperty<RankFourTensor>* LinearViscoelasticityBase::_first_elasticity_tensor_inv

protectedinherited

Definition at line 218 of file LinearViscoelasticityBase.h.

Referenced by LinearViscoelasticityBase::computeQpViscoelasticPropertiesInv().

◆ _first_elasticity_tensor_inv_old

const MaterialProperty<RankFourTensor>& GeneralizedKelvinVoigtBase::_first_elasticity_tensor_inv_old

protectedinherited

Definition at line 49 of file GeneralizedKelvinVoigtBase.h.

Referenced by GeneralizedKelvinVoigtBase::updateQpViscousStrains().

◆ _first_elasticity_tensor_old

const MaterialProperty<RankFourTensor>& GeneralizedKelvinVoigtBase::_first_elasticity_tensor_old

protectedinherited

old material properties required for the update of the viscoelastic strain

Definition at line 48 of file GeneralizedKelvinVoigtBase.h.

Referenced by GeneralizedKelvinVoigtBase::updateQpViscousStrains().

◆ _force_recompute_properties

bool LinearViscoelasticityBase::_force_recompute_properties

protectedinherited

If activated, the time-stepping scheme will be re-initialized at each step of the solver.

This may be required for models in which the mechanical properties vary following other variables. If the mechanical properties are constant through the time step, this can be set to false.

Definition at line 268 of file LinearViscoelasticityBase.h.

Referenced by LinearViscoelasticityBase::computeQpElasticityTensor().