PresetDisplacement Class Reference

This class applies a displacement time history on a given boundary in a given direction. More...

#include <PresetDisplacement.h>

Inheritance diagram for PresetDisplacement:

Public Member Functions
	PresetDisplacement (const InputParameters &parameters)

Static Public Member Functions
static InputParameters	validParams ()

Protected Member Functions
virtual Real	computeQpValue ()

Protected Attributes
const VariableValue &	_u_old
const Real	_scale_factor
const Function &	_function
const VariableValue &	_vel_old
const VariableValue &	_accel_old
const Real	_beta

Detailed Description

This class applies a displacement time history on a given boundary in a given direction.

The displacement is converted to acceleration using backward euler differentiation and then integrated using newmark time integration scheme to get the displacement. This modified displacement is then applied to the boundary.

Definition at line 22 of file PresetDisplacement.h.

Constructor & Destructor Documentation

PresetDisplacement()

PresetDisplacement::PresetDisplacement

(

const InputParameters &

parameters

)

Definition at line 37 of file PresetDisplacement.C.

  : DirichletBCBase(parameters),
    _u_old(valueOld()),
    _scale_factor(parameters.get<Real>("scale_factor")),
    _function(getFunction("function")),
    _vel_old(coupledValueOld("velocity")),
    _accel_old(coupledValueOld("acceleration")),
    _beta(getParam<Real>("beta"))
{
}

Member Function Documentation

computeQpValue()

Real PresetDisplacement::computeQpValue ( )

protectedvirtual

Definition at line 49 of file PresetDisplacement.C.

{
  Point p;
  Real vel = _function.timeDerivative(_t, p);
  Real vel_old = _function.timeDerivative(_t - _dt, p);
  Real accel = (vel - vel_old) / _dt;
 
  return _u_old[_qp] + _dt * _vel_old[_qp] +
         ((0.5 - _beta) * _accel_old[_qp] + _beta * accel) * _dt * _dt;
}

validParams()

InputParameters PresetDisplacement::validParams ( )

static

Definition at line 18 of file PresetDisplacement.C.

{
  InputParameters params = DirichletBCBase::validParams();
  params.addClassDescription(
      "Prescribe the displacement on a given boundary in a given direction.");
 
  params.addParam<Real>("scale_factor", 1, "Scale factor if function is given.");
  params.addParam<FunctionName>("function", "1", "Function describing the displacement.");
  params.addRequiredCoupledVar("velocity", "The velocity variable.");
  params.addRequiredCoupledVar("acceleration", "The acceleration variable.");
  params.addRequiredParam<Real>("beta", "beta parameter for Newmark time integration.");
 
  // Forcefully preset the BC
  params.set<bool>("preset") = true;
  params.suppressParameter<bool>("preset");
 
  return params;
}

Member Data Documentation

_accel_old

const VariableValue& PresetDisplacement::_accel_old

protected

Definition at line 36 of file PresetDisplacement.h.

Referenced by computeQpValue().

_beta

const Real PresetDisplacement::_beta

protected

Definition at line 37 of file PresetDisplacement.h.

Referenced by computeQpValue().

_function

const Function& PresetDisplacement::_function

protected

Definition at line 34 of file PresetDisplacement.h.

Referenced by computeQpValue().

_scale_factor

const Real PresetDisplacement::_scale_factor

protected

Definition at line 33 of file PresetDisplacement.h.

_u_old

const VariableValue& PresetDisplacement::_u_old

protected

Definition at line 32 of file PresetDisplacement.h.

Referenced by computeQpValue().

_vel_old

const VariableValue& PresetDisplacement::_vel_old

protected

Definition at line 35 of file PresetDisplacement.h.

Referenced by computeQpValue().

---

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

• tensor_mechanics/include/bcs/PresetDisplacement.h
• tensor_mechanics/src/bcs/PresetDisplacement.C