ProcessLib::TimeDecayDirichletBoundaryCondition Class Reference

Detailed Description

Dirichlet boundary condition with time-dependent decay.

This boundary condition imposes the initial values of the specified primary variable at the boundary nodes, scaled by a time-dependent parameter. The scaling parameter should be monotonically decreasing over time, representing progressive removal or reduction of support (e.g., during excavation). Typically, the scaling factor starts at 1 ( \( g(0, \mathbf{x}) = 1 \)) at the initial time and decreases to 0 ( \( g(t_e, \mathbf{x}) = 0 \)) at the end of the process ( \( t_e \)). The value of the boundary condition is given by

\[ g(t, \mathbf{x}) (u_0(\mathbf{x}) - u_{\text{min}}) + u_{\text{min}} \]

, where \( u_0(\mathbf{x}) \) is the initial value of the primary variable at the boundary node \( \mathbf{x} \), and \( u_{\text{min}} \) is the user-defined lower limit of the boundary value.

Definition at line 49 of file TimeDecayDirichletBoundaryCondition.h.

#include <TimeDecayDirichletBoundaryCondition.h>

Inheritance diagram for ProcessLib::TimeDecayDirichletBoundaryCondition:

Collaboration diagram for ProcessLib::TimeDecayDirichletBoundaryCondition:

Public Member Functions
	TimeDecayDirichletBoundaryCondition (int const variable_id, int const component_id, MeshLib::Mesh const &boundary_mesh, NumLib::LocalToGlobalIndexMap const &dof_table_bulk, ParameterLib::Parameter< double > const &time_decay_parameter, double const lower_limit)
	Constructs a time decay Dirichlet boundary condition.
void	getEssentialBCValues (const double t, GlobalVector const &x, NumLib::IndexValueVector< GlobalIndexType > &bc_values) const override
	Writes the values of essential BCs to bc_values.
Public Member Functions inherited from ProcessLib::BoundaryCondition
virtual void	applyNaturalBC (const double, std::vector< GlobalVector * > const &, int const, GlobalMatrix *, GlobalVector &, GlobalMatrix *)
virtual void	preTimestep (const double, std::vector< GlobalVector * > const &, int const)
virtual void	postTimestep (const double, std::vector< GlobalVector * > const &, int const)
virtual	~BoundaryCondition ()=default

Private Member Functions
void	setInitialValues (GlobalVector const &x) const

Private Attributes
int const	variable_id_
int const	component_id_
MeshLib::Mesh const &	boundary_mesh_
std::unique_ptr< NumLib::LocalToGlobalIndexMap > const	dof_table_boundary_
ParameterLib::Parameter< double > const &	time_decay_parameter_
double const	lower_limit_
	The lower limit of the boundary value.
std::vector< double >	initial_x_values_
bool	initial_values_are_set_ = false

Constructor & Destructor Documentation

TimeDecayDirichletBoundaryCondition()

ProcessLib::TimeDecayDirichletBoundaryCondition::TimeDecayDirichletBoundaryCondition ( int const variable_id, int const component_id, MeshLib::Mesh const & boundary_mesh, NumLib::LocalToGlobalIndexMap const & dof_table_bulk, ParameterLib::Parameter< double > const & time_decay_parameter, double const lower_limit )

explicit

Constructs a time decay Dirichlet boundary condition.

Parameters

variable_id	The ID of the variable to which the condition are applied.
component_id	The ID of the variable component to which the condition are applied.
boundary_mesh	The mesh representing the boundary where the nodal forces are applied.
dof_table_bulk	A unique pointer to the DOF table created from the boundary mesh.
time_decay_parameter	A parameter that defines the scaling factor of the initial nodal values. It should be a monotonic decrease parameter, meaning it should decrease over time.
lower_limit	The lower limit of the boundary value.

Definition at line 41 of file TimeDecayDirichletBoundaryCondition.cpp.

    : variable_id_(variable_id),
      component_id_(component_id),
      boundary_mesh_(boundary_mesh),
      dof_table_boundary_(createBoundaryDOFTable(
          variable_id, component_id, boundary_mesh, dof_table_bulk)),
      time_decay_parameter_(time_decay_parameter),
      lower_limit_(lower_limit)
{
}

Member Function Documentation

getEssentialBCValues()

void ProcessLib::TimeDecayDirichletBoundaryCondition::getEssentialBCValues ( const double , GlobalVector const & , NumLib::IndexValueVector< GlobalIndexType > &  ) const

overridevirtual

Writes the values of essential BCs to bc_values.

Reimplemented from ProcessLib::BoundaryCondition.

Definition at line 84 of file TimeDecayDirichletBoundaryCondition.cpp.

{
    DBUG("Apply TimeDecayDirichlet boundary bondition.");
 
    if (!initial_values_are_set_)
    {
        setInitialValues(x);
        initial_values_are_set_ = true;
        if (initial_x_values_.empty())
        {
            return;  // No node in the boundary.
        }
    }
 
    bc_values.ids.clear();
    bc_values.values.clear();
 
    bc_values.ids.reserve(initial_x_values_.size());
    bc_values.values.reserve(initial_x_values_.size());
 
    std::size_t idx = 0;
    for (auto const* node : boundary_mesh_.getNodes())
    {
        auto const node_id = node->getID();
        MeshLib::Location const l{boundary_mesh_.getID(),
                                  MeshLib::MeshItemType::Node, node_id};
 
        auto const global_index =
            dof_table_boundary_->getGlobalIndex(l, variable_id_, component_id_);
 
        if (global_index == NumLib::MeshComponentMap::nop)
        {
            continue;
        }
        // For the DDC approach (e.g. with PETSc option), the negative
        // index of global_index means that the entry by that index is a
        // ghost one, which should be dropped. Especially for PETSc
        // routines MatZeroRows and MatZeroRowsColumns, which are called
        // to apply the Dirichlet BC, the negative index is not accepted
        // like other matrix or vector PETSc routines. Therefore, the
        // following if-condition is applied.
        if (global_index >= 0) [[likely]]
        {
            ParameterLib::SpatialPosition pos;
            pos.setNodeID(node_id);
            pos.setCoordinates(*node);
 
            bc_values.values.push_back(
                time_decay_parameter_(t, pos).front() *
                    (initial_x_values_[idx] - lower_limit_) +
                lower_limit_);
            bc_values.ids.push_back(global_index);
            idx++;
        }
    }
}

References boundary_mesh_, component_id_, DBUG(), dof_table_boundary_, MeshLib::Mesh::getID(), MeshLib::Mesh::getNodes(), NumLib::IndexValueVector< typename >::ids, initial_values_are_set_, initial_x_values_, lower_limit_, MeshLib::Node, NumLib::MeshComponentMap::nop, ParameterLib::SpatialPosition::setCoordinates(), setInitialValues(), ParameterLib::SpatialPosition::setNodeID(), time_decay_parameter_, NumLib::IndexValueVector< typename >::values, and variable_id_.

setInitialValues()

void ProcessLib::TimeDecayDirichletBoundaryCondition::setInitialValues ( GlobalVector const & x ) const

private

Definition at line 57 of file TimeDecayDirichletBoundaryCondition.cpp.

{
    initial_x_values_.clear();
    for (auto const& l : MeshLib::views::meshLocations(
             boundary_mesh_, MeshLib::MeshItemType::Node))
    {
        auto const global_index =
            dof_table_boundary_->getGlobalIndex(l, variable_id_, component_id_);
        if (global_index == NumLib::MeshComponentMap::nop)
        {
            continue;
        }
        // For the DDC approach (e.g. with PETSc option), the negative
        // index of global_index means that the entry by that index is
        // a ghost one, which should be dropped. Especially for PETSc
        // routines MatZeroRows and MatZeroRowsColumns, which are
        // called to apply the Dirichlet BC, the negative index is not
        // accepted like other matrix or vector PETSc routines.
        // Therefore, the following if-condition is applied.
        if (global_index >= 0) [[likely]]
        {
            initial_x_values_.push_back(x.get(global_index));
        }
    }
}

References boundary_mesh_, component_id_, dof_table_boundary_, MathLib::EigenVector::get(), initial_x_values_, MeshLib::views::meshLocations(), MeshLib::Node, NumLib::MeshComponentMap::nop, and variable_id_.

Referenced by getEssentialBCValues().

Member Data Documentation

boundary_mesh_

MeshLib::Mesh const& ProcessLib::TimeDecayDirichletBoundaryCondition::boundary_mesh_

private

Definition at line 84 of file TimeDecayDirichletBoundaryCondition.h.

Referenced by getEssentialBCValues(), and setInitialValues().

component_id_

int const ProcessLib::TimeDecayDirichletBoundaryCondition::component_id_

private

Definition at line 82 of file TimeDecayDirichletBoundaryCondition.h.

Referenced by getEssentialBCValues(), and setInitialValues().

dof_table_boundary_

std::unique_ptr<NumLib::LocalToGlobalIndexMap> const ProcessLib::TimeDecayDirichletBoundaryCondition::dof_table_boundary_

private

Definition at line 86 of file TimeDecayDirichletBoundaryCondition.h.

Referenced by getEssentialBCValues(), and setInitialValues().

initial_values_are_set_

bool ProcessLib::TimeDecayDirichletBoundaryCondition::initial_values_are_set_ = false

mutableprivate

Definition at line 107 of file TimeDecayDirichletBoundaryCondition.h.

Referenced by getEssentialBCValues().

initial_x_values_

std::vector<double> ProcessLib::TimeDecayDirichletBoundaryCondition::initial_x_values_

mutableprivate

This vector is used to store the initial values at the boundary nodes before they are scaled by the time decay parameter.

Definition at line 105 of file TimeDecayDirichletBoundaryCondition.h.

Referenced by getEssentialBCValues(), and setInitialValues().

lower_limit_

double const ProcessLib::TimeDecayDirichletBoundaryCondition::lower_limit_

private

The lower limit of the boundary value.

Definition at line 101 of file TimeDecayDirichletBoundaryCondition.h.

Referenced by getEssentialBCValues().

time_decay_parameter_

ParameterLib::Parameter<double> const& ProcessLib::TimeDecayDirichletBoundaryCondition::time_decay_parameter_

private

A monotonically decreasing parameter that defines the scaling factor of the initial values of the specified primary variable. It is a time- and position-dependent release parameter \( g(t, \mathbf{x}) \) representing the progressive removal of support over time, e.g., \( g(0, \mathbf{x}) = 1 \) and \( g(t_e, \mathbf{x}) = 0, \) where \( t_e \) is the end time of decay, and \( \frac{\partial g}{\partial t} < 0 \).

Definition at line 98 of file TimeDecayDirichletBoundaryCondition.h.

Referenced by getEssentialBCValues().

variable_id_

int const ProcessLib::TimeDecayDirichletBoundaryCondition::variable_id_

private

Definition at line 81 of file TimeDecayDirichletBoundaryCondition.h.

Referenced by getEssentialBCValues(), and setInitialValues().

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

• ProcessLib/BoundaryConditionAndSourceTerm/TimeDecayDirichletBoundaryCondition.h
• ProcessLib/BoundaryConditionAndSourceTerm/TimeDecayDirichletBoundaryCondition.cpp