PresetDisplacement.C

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//* This file is part of the MOOSE framework
//* https://mooseframework.inl.gov
//*
//* All rights reserved, see COPYRIGHT for full restrictions
//* https://github.com/idaholab/moose/blob/master/COPYRIGHT
//*
//* Licensed under LGPL 2.1, please see LICENSE for details
//* https://www.gnu.org/licenses/lgpl-2.1.html
 
#include "PresetDisplacement.h"
#include "Function.h"
 
registerMooseObject("SolidMechanicsApp", PresetDisplacement);
 
InputParameters
PresetDisplacement::validParams()
{
  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;
}
 
PresetDisplacement::PresetDisplacement(const InputParameters & parameters)
  : 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"))
{
}
 
Real
PresetDisplacement::computeQpValue()
{
  Real vel = _function.timeDerivative(_t);
  Real vel_old = _function.timeDerivative(_t - _dt);
  Real accel = (vel - vel_old) / _dt;
 
  return _u_old[_qp] + _dt * _vel_old[_qp] +
         ((0.5 - _beta) * _accel_old[_qp] + _beta * accel) * _dt * _dt;
}