GRINS::HookesLaw Class Reference

Elasticity tensor for Hooke's law. More...

#include <hookes_law.h>

Inheritance diagram for GRINS::HookesLaw:

Collaboration diagram for GRINS::HookesLaw:

Public Member Functions
	HookesLaw (const GetPot &input)
	HookesLaw (const GetPot &input, const std::string &material)
virtual	~HookesLaw ()
Public Member Functions inherited from GRINS::StressStrainLaw< HookesLaw >
	StressStrainLaw ()
virtual	~StressStrainLaw ()
void	compute_stress (unsigned int dim, const libMesh::TensorValue< libMesh::Real > &g_contra, const libMesh::TensorValue< libMesh::Real > &g_cov, const libMesh::TensorValue< libMesh::Real > &G_contra, const libMesh::TensorValue< libMesh::Real > &G_cov, libMesh::TensorValue< libMesh::Real > &stress)
void	compute_stress_and_elasticity (unsigned int dim, const libMesh::TensorValue< libMesh::Real > &g_contra, const libMesh::TensorValue< libMesh::Real > &g_cov, const libMesh::TensorValue< libMesh::Real > &G_contra, const libMesh::TensorValue< libMesh::Real > &G_cov, libMesh::TensorValue< libMesh::Real > &stress, ElasticityTensor &C)
libMesh::Real	compute_33_stress (const libMesh::TensorValue< libMesh::Real > &g_contra, const libMesh::TensorValue< libMesh::Real > &g_cov, const libMesh::TensorValue< libMesh::Real > &G_contra, const libMesh::TensorValue< libMesh::Real > &G_cov)
	This is primarily a helper function for the plane stress cases. More...
Public Member Functions inherited from GRINS::ParameterUser
	ParameterUser (const std::string &user_name)
virtual	~ParameterUser ()
virtual void	set_parameter (libMesh::Number &param_variable, const GetPot &input, const std::string &param_name, libMesh::Number param_default)
	Each subclass can simultaneously read a parameter value from. More...
virtual void	set_parameter (libMesh::ParsedFunction< libMesh::Number, libMesh::Gradient > &func, const GetPot &input, const std::string &func_param_name, const std::string &param_default)
	Each subclass can simultaneously read a parsed function from. More...
virtual void	set_parameter (libMesh::ParsedFEMFunction< libMesh::Number > &func, const GetPot &input, const std::string &func_param_name, const std::string &param_default)
	Each subclass can simultaneously read a parsed function from. More...
virtual void	move_parameter (const libMesh::Number &old_parameter, libMesh::Number &new_parameter)
	When cloning an object, we need to update parameter pointers. More...
virtual void	move_parameter (const libMesh::ParsedFunction< libMesh::Number, libMesh::Gradient > &old_func, libMesh::ParsedFunction< libMesh::Number, libMesh::Gradient > &new_func)
	When cloning an object, we need to update parameter pointers. More...
virtual void	move_parameter (const libMesh::ParsedFEMFunction< libMesh::Number > &old_func, libMesh::ParsedFEMFunction< libMesh::Number > &new_func)
	When cloning an object, we need to update parameter pointers. More...
virtual void	register_parameter (const std::string &param_name, libMesh::ParameterMultiAccessor< libMesh::Number > &param_pointer) const
	Each subclass will register its copy of an independent. More...

Private Member Functions
	HookesLaw ()
void	read_input_options (const GetPot &input)
	Parse properties from input. More...
void	compute_stress_imp (unsigned int dim, const libMesh::TensorValue< libMesh::Real > &g_contra, const libMesh::TensorValue< libMesh::Real > &g_cov, const libMesh::TensorValue< libMesh::Real > &G_contra, const libMesh::TensorValue< libMesh::Real > &G_cov, libMesh::TensorValue< libMesh::Real > &stress)
void	compute_stress_and_elasticity_imp (unsigned int dim, const libMesh::TensorValue< libMesh::Real > &g_contra, const libMesh::TensorValue< libMesh::Real > &g_cov, const libMesh::TensorValue< libMesh::Real > &G_contra, const libMesh::TensorValue< libMesh::Real > &G_cov, libMesh::TensorValue< libMesh::Real > &stress, ElasticityTensor &C)
libMesh::Real	compute_33_stress_imp (const libMesh::TensorValue< libMesh::Real > &g_contra, const libMesh::TensorValue< libMesh::Real > &g_cov, const libMesh::TensorValue< libMesh::Real > &G_contra, const libMesh::TensorValue< libMesh::Real > &G_cov)

Private Attributes
ElasticityTensor	_C
libMesh::Real	_lambda
	Lam\'{e} constant. More...
libMesh::Real	_mu
	Lam\'{e} constant. More...

Friends
class	StressStrainLaw< HookesLaw >

Additional Inherited Members
Static Public Attributes inherited from GRINS::ParameterUser
static std::string	zero_vector_function = std::string("{0}")
	A parseable function string with LIBMESH_DIM components, all 0. More...

Detailed Description

Elasticity tensor for Hooke's law.

Uses Lam\'{e} constants, but can parse Young's modulus and Poisson's ratio if desired. By default, is constructed for Cartesian coordinate systems. If working with curvilinear coordinate systems, the user should call the set_deformation method before calling operator().

Definition at line 46 of file hookes_law.h.

Constructor & Destructor Documentation

GRINS::HookesLaw::HookesLaw

(

const GetPot &

input

)

Definition at line 38 of file hookes_law.C.

References grins_warning, and read_input_options().

    : StressStrainLaw<HookesLaw>(),
      ParameterUser("HookesLaw"),
      _C(),
      _lambda(0.0),
      _mu(0.0)
  {
    // Warning about this constructor being deprecated
    {
      std::string warning = "WARNING: Use of this constructor is DEPRECATED.\n";
      warning += "         Please update to use constructor with input material name.\n";
      grins_warning(warning);
    }

    this->read_input_options(input);

    return;
  }

GRINS::HookesLaw::HookesLaw	(	const GetPot &	input,
		const std::string &	material
	)

Todo:

we'll need a special accessor to give ParameterUser access to these

Todo:

we'll need a special accessor to give ParameterUser access to these

Definition at line 57 of file hookes_law.C.

References _lambda, _mu, GRINS::MaterialsParsing::dep_input_warning(), GRINS::MaterialsParsing::duplicate_input_test(), grins_warning, and GRINS::ParameterUser::set_parameter().

    : StressStrainLaw<HookesLaw>(),
      ParameterUser("HookesLaw"),
      _C(),
      _lambda(0.0),
      _mu(0.0)
  {
    MaterialsParsing::duplicate_input_test(input,
                                           "Materials/"+material+"/StressStrainLaw/HookesLaw/lambda",
                                           "Physics/HookesLaw/lambda");
    MaterialsParsing::duplicate_input_test(input,
                                           "Materials/"+material+"/StressStrainLaw/HookesLaw/mu",
                                           "Physics/HookesLaw/mu");
    MaterialsParsing::duplicate_input_test(input,
                                           "Materials/"+material+"/StressStrainLaw/HookesLaw/E",
                                           "Physics/HookesLaw/E");
    MaterialsParsing::duplicate_input_test(input,
                                           "Materials/"+material+"/StressStrainLaw/HookesLaw/nu",
                                           "Physics/HookesLaw/nu");

    // Parse the new version
    if( input.have_variable("Materials/"+material+"/StressStrainLaw/HookesLaw/lambda") &&
        input.have_variable("Materials/"+material+"/StressStrainLaw/HookesLaw/mu") )
      {
        this->set_parameter
          (_lambda, input, "Materials/"+material+"/StressStrainLaw/HookesLaw/lambda", 0.0);
        this->set_parameter
          (_mu, input, "Materials/"+material+"/StressStrainLaw/HookesLaw/mu", 0.0);
      }
    else if( input.have_variable("Materials/"+material+"/StressStrainLaw/HookesLaw/E") &&
             input.have_variable("Materials/"+material+"/StressStrainLaw/HookesLaw/nu") )
      {
        libMesh::Real E  = input("Materials/"+material+"/StressStrainLaw/HookesLaw/E", 0.0);
        libMesh::Real nu = input("Materials/"+material+"/StressStrainLaw/HookesLaw/nu", 0.0);
        _lambda = nu*E/( (1+nu)*(1-2*nu) );
        _mu = E/(2*(1+nu));
      }
    // Parse the old version
    else if( input.have_variable("Physics/HookesLaw/lambda") &&
             input.have_variable("Physics/HookesLaw/mu") )
      {
        MaterialsParsing::dep_input_warning( "Physics/HookesLaw/lambda",
                                             "StressStrainLaw/HookesLaw/lambda" );
        MaterialsParsing::dep_input_warning( "Physics/HookesLaw/mu",
                                             "StressStrainLaw/HookesLaw/mu" );

        this->set_parameter
          (_lambda, input, "Physics/HookesLaw/lambda", 0.0);
        this->set_parameter
          (_mu, input, "Physics/HookesLaw/mu", 0.0);
      }
    else if( input.have_variable("Physics/HookesLaw/E") &&
              input.have_variable("Physics/HookesLaw/nu") )
      {
        MaterialsParsing::dep_input_warning( "Physics/HookesLaw/E",
                                             "StressStrainLaw/HookesLaw/E" );
        MaterialsParsing::dep_input_warning( "Physics/HookesLaw/nu",
                                             "StressStrainLaw/HookesLaw/nu" );

        libMesh::Real E  = input("Physics/HookesLaw/E", 0.0);
        libMesh::Real nu = input("Physics/HookesLaw/nu", 0.0);
        _lambda = nu*E/( (1+nu)*(1-2*nu) );
        _mu = E/(2*(1+nu));
      }
    else
      {
        libmesh_error_msg("ERROR: Could not find consistent HookesLaw input!");
      }

    // mu should be positive
    if( _mu <= 0.0 )
      libmesh_error_msg("ERROR: Detected non-positive shear modulus!");

    // Technically, lambda can be negative, but it's weird. Let's warn about it.
    if( _lambda <= 0.0 )
      {
        std::string warning = "WARNING: Detected non-positive Lame parameter";
        grins_warning(warning);
      }
  }

GRINS::HookesLaw::~HookesLaw ( )

virtual

Definition at line 140 of file hookes_law.C.

  {
    return;
  }

GRINS::HookesLaw::HookesLaw ( )

private

Member Function Documentation

libMesh::Real GRINS::HookesLaw::compute_33_stress_imp ( const libMesh::TensorValue< libMesh::Real > &  g_contra, const libMesh::TensorValue< libMesh::Real > &  g_cov, const libMesh::TensorValue< libMesh::Real > &  G_contra, const libMesh::TensorValue< libMesh::Real > &  G_cov  )

private

Definition at line 226 of file hookes_law.C.

References _lambda, and _mu.

  {
    libMesh::Real sigma_33 = 0.0;

    for( unsigned int k = 0; k < 3; k++ )
      {
        for( unsigned int l = 0; l < 3; l++ )
          {
            libMesh::Real strain_kl = 0.5*(G_cov(k,l) - g_cov(k,l));

            libMesh::Real C = _lambda*g_contra(2,2)*g_contra(k,l) +
              _mu*(g_contra(2,k)*g_contra(2,l) + g_contra(2,l)*g_contra(2,k));

            sigma_33 += C*strain_kl;
          }
      }

    return sigma_33;
  }

void GRINS::HookesLaw::compute_stress_and_elasticity_imp ( unsigned int  dim, const libMesh::TensorValue< libMesh::Real > &  g_contra, const libMesh::TensorValue< libMesh::Real > &  g_cov, const libMesh::TensorValue< libMesh::Real > &  G_contra, const libMesh::TensorValue< libMesh::Real > &  G_cov, libMesh::TensorValue< libMesh::Real > &  stress, ElasticityTensor &  C  )

private

Definition at line 211 of file hookes_law.C.

References _C, and compute_stress_imp().

  {
    this->compute_stress_imp(dim,g_contra,g_cov,G_contra,G_cov,stress);

    C = _C;

    return;
  }

void GRINS::HookesLaw::compute_stress_imp ( unsigned int  dim, const libMesh::TensorValue< libMesh::Real > &  g_contra, const libMesh::TensorValue< libMesh::Real > &  g_cov, const libMesh::TensorValue< libMesh::Real > &  G_contra, const libMesh::TensorValue< libMesh::Real > &  G_cov, libMesh::TensorValue< libMesh::Real > &  stress  )

private

Definition at line 180 of file hookes_law.C.

References _C, _lambda, and _mu.

Referenced by compute_stress_and_elasticity_imp().

  {
    stress.zero();

    for( unsigned int i = 0; i < dim; i++ )
      {
        for( unsigned int j = 0; j < dim; j++ )
          {
            for( unsigned int k = 0; k < dim; k++ )
              {
                for( unsigned int l = 0; l < dim; l++ )
                  {
                    libMesh::Real strain_kl = 0.5*(G_cov(k,l) - g_cov(k,l));

                    _C(i,j,k,l) = _lambda*g_contra(i,j)*g_contra(k,l) +
                                  _mu*(g_contra(i,k)*g_contra(j,l) + g_contra(i,l)*g_contra(j,k));

                    stress(i,j) += _C(i,j,k,l)*strain_kl;
                  }
              }
          }
      }

    return;
  }

void GRINS::HookesLaw::read_input_options ( const GetPot &  input )

private

Parse properties from input.

Definition at line 145 of file hookes_law.C.

References _lambda, _mu, and GRINS::ParameterUser::set_parameter().

Referenced by HookesLaw().

  {
    // We'd better have either Lam\'{e} constants or E and nu
    if( ( !input.have_variable("Physics/HookesLaw/lambda") || 
          !input.have_variable("Physics/HookesLaw/mu") ) &&
        ( !input.have_variable("Physics/HookesLaw/E") || 
          !input.have_variable("Physics/HookesLaw/nu") ) )
      {
        std::cerr << "Error: Must specify either Lame constants lambda and mu or" << std::endl
                  << "       Young's modulus and Poisson's ratio." << std::endl;
        libmesh_error();
      }

    if( input.have_variable("Physics/HookesLaw/lambda") )
      this->set_parameter
        (_lambda, input, "Physics/HookesLaw/lambda", 0.0);
    
    if( input.have_variable("Physics/HookesLaw/mu") )
      this->set_parameter
        (_mu, input, "Physics/HookesLaw/mu", 0.0);
        
    if( input.have_variable("Physics/HookesLaw/E") && 
        input.have_variable("Physics/HookesLaw/nu") )
      {
        // FIXME - we'll need a special accessor to give parameter
        // access to these
        libMesh::Real E  = input("Physics/HookesLaw/E", 0.0);
        libMesh::Real nu = input("Physics/HookesLaw/nu", 0.0);
        _lambda = nu*E/( (1+nu)*(1-2*nu) );
        _mu = E/(2*(1+nu));
      }

    return;
  }

Friends And Related Function Documentation

friend class StressStrainLaw< HookesLaw >

friend

Definition at line 58 of file hookes_law.h.

Member Data Documentation

ElasticityTensor GRINS::HookesLaw::_C

private

Definition at line 87 of file hookes_law.h.

Referenced by compute_stress_and_elasticity_imp(), and compute_stress_imp().

libMesh::Real GRINS::HookesLaw::_lambda

private

Lam\'{e} constant.

Definition at line 90 of file hookes_law.h.

Referenced by compute_33_stress_imp(), compute_stress_imp(), HookesLaw(), and read_input_options().

libMesh::Real GRINS::HookesLaw::_mu

private

Lam\'{e} constant.

Definition at line 93 of file hookes_law.h.

Referenced by compute_33_stress_imp(), compute_stress_imp(), HookesLaw(), and read_input_options().

---

The documentation for this class was generated from the following files:

• src/properties/include/grins/hookes_law.h
• src/properties/src/hookes_law.C