ComputeMeanThermalExpansionEigenstrainBase is a base class for computing the thermal expansion eigenstrain according to a temperature-dependent mean thermal expansion defined in a derived class. More...

#include <ComputeMeanThermalExpansionEigenstrainBase.h>

Inheritance diagram for ComputeMeanThermalExpansionEigenstrainBase:

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Public Member Functions
	ComputeMeanThermalExpansionEigenstrainBase (const InputParameters &parameters)

Static Public Member Functions
static InputParameters	validParams ()

Protected Member Functions
virtual void	computeThermalStrain (Real &thermal_strain, Real &instantaneous_cte) override

virtual Real	referenceTemperature ()=0

virtual Real	meanThermalExpansionCoefficient (const Real temperature)=0

virtual Real	meanThermalExpansionCoefficientDerivative (const Real temperature)=0

virtual void	computeQpEigenstrain () override

Protected Attributes
const VariableValue &	_temperature

MaterialProperty< RankTwoTensor > &	_deigenstrain_dT

const VariableValue &	_stress_free_temperature

Detailed Description

ComputeMeanThermalExpansionEigenstrainBase is a base class for computing the thermal expansion eigenstrain according to a temperature-dependent mean thermal expansion defined in a derived class.

This is defined as the total total linear strain ( \(\delta L / L\)) at a given temperature relative to a reference temperature at which \(\delta L = 0\).

Based on: M. Niffenegger and K. Reichlin. The proper use of thermal expansion coefficients in finite element calculations. Nuclear Engineering and Design, 243:356-359, Feb. 2012.

Definition at line 30 of file ComputeMeanThermalExpansionEigenstrainBase.h.

Constructor & Destructor Documentation

◆ ComputeMeanThermalExpansionEigenstrainBase()

ComputeMeanThermalExpansionEigenstrainBase::ComputeMeanThermalExpansionEigenstrainBase ( const InputParameters & parameters )

Definition at line 24 of file ComputeMeanThermalExpansionEigenstrainBase.C.

   : ComputeThermalExpansionEigenstrainBase(parameters)
 {
 }

Member Function Documentation

◆ computeQpEigenstrain()

void ComputeThermalExpansionEigenstrainBase::computeQpEigenstrain ( )

overrideprotectedvirtualinherited

Definition at line 38 of file ComputeThermalExpansionEigenstrainBase.C.

 {
   Real thermal_strain = 0.0;
  
   // instantaneous_cte is just the derivative of thermal_strain with respect to temperature
   Real instantaneous_cte = 0.0;
  
   computeThermalStrain(thermal_strain, instantaneous_cte);
  
   _eigenstrain[_qp].zero();
   _eigenstrain[_qp].addIa(thermal_strain);
  
   _deigenstrain_dT[_qp].zero();
   _deigenstrain_dT[_qp].addIa(instantaneous_cte);
 }

◆ computeThermalStrain()

void ComputeMeanThermalExpansionEigenstrainBase::computeThermalStrain	(	Real &	thermal_strain,
		Real &	instantaneous_cte
	)

overrideprotectedvirtual

Implements ComputeThermalExpansionEigenstrainBase.

Definition at line 31 of file ComputeMeanThermalExpansionEigenstrainBase.C.

 {
   const Real small = libMesh::TOLERANCE;
  
   const Real reference_temperature = referenceTemperature();
   const Real & current_temp = _temperature[_qp];
   const Real current_alphabar = meanThermalExpansionCoefficient(current_temp);
   const Real thexp_current_temp = current_alphabar * (current_temp - reference_temperature);
  
   // Mean linear thermal expansion coefficient relative to the reference temperature
   // evaluated at stress_free_temperature.  This is
   // \f$\bar{\alpha} = (\delta L(T_{sf}) / L) / (T_{sf} - T_{ref})\f$
   // where \f$T_sf\f$ is the stress-free temperature and \f$T_{ref}\f$ is the reference temperature.
   const Real alphabar_stress_free_temperature =
       meanThermalExpansionCoefficient(_stress_free_temperature[_qp]);
   // Thermal expansion relative to the reference temperature evaluated at stress_free_temperature
   // \f$(\delta L(T_sf) / L)\f$, where \f$T_sf\f$ is the stress-free temperature.
   const Real thexp_stress_free_temperature =
       alphabar_stress_free_temperature * (_stress_free_temperature[_qp] - referenceTemperature());
  
   // Per M. Niffenegger and K. Reichlin (2012), thermal_strain should be divided
   // by (1.0 + thexp_stress_free_temperature) to account for the ratio of
   // the length at the stress-free temperature to the length at the reference
   // temperature. It can be neglected because it is very close to 1,
   // but we include it for completeness here.
  
   thermal_strain =
       (thexp_current_temp - thexp_stress_free_temperature) / (1.0 + thexp_stress_free_temperature);
  
   const Real dalphabar_dT = meanThermalExpansionCoefficientDerivative(current_temp);
   const Real numerator = dalphabar_dT * (current_temp - reference_temperature) + current_alphabar;
   const Real denominator =
       1.0 +
       alphabar_stress_free_temperature * (_stress_free_temperature[_qp] - reference_temperature);
   if (denominator < small)
     mooseError("Denominator too small in thermal strain calculation");
   instantaneous_cte = numerator / denominator;
 }

◆ meanThermalExpansionCoefficient()

virtual Real ComputeMeanThermalExpansionEigenstrainBase::meanThermalExpansionCoefficient ( const Real temperature )

protectedpure virtual

Implemented in ComputeMeanThermalExpansionFunctionEigenstrain.

Referenced by computeThermalStrain().

◆ meanThermalExpansionCoefficientDerivative()

virtual Real ComputeMeanThermalExpansionEigenstrainBase::meanThermalExpansionCoefficientDerivative ( const Real temperature )

protectedpure virtual

Implemented in ComputeMeanThermalExpansionFunctionEigenstrain.

Referenced by computeThermalStrain().

◆ referenceTemperature()

virtual Real ComputeMeanThermalExpansionEigenstrainBase::referenceTemperature ( )

protectedpure virtual

Implemented in ComputeMeanThermalExpansionFunctionEigenstrain.

Referenced by computeThermalStrain().

◆ validParams()

InputParameters ComputeMeanThermalExpansionEigenstrainBase::validParams ( )

static

Definition at line 16 of file ComputeMeanThermalExpansionEigenstrainBase.C.

 {
   InputParameters params = ComputeThermalExpansionEigenstrainBase::validParams();
   params.addClassDescription("Base class for models that compute eigenstrain due to mean"
                              "thermal expansion as a function of temperature");
   return params;
 }