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material_damage_iterative.cc
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Tue, Nov 19, 15:38

material_damage_iterative.cc
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/**
* @file material_damage_iterative.cc
*
* @author Aurelia Isabel Cuba Ramos <aurelia.cubaramos@epfl.ch>
*
*
* @brief Specialization of the class material damage to damage only one gauss
* point at a time and propagate damage in a linear way. Max principal stress
* criterion is used as a failure criterion.
*
* @section LICENSE
*
* Copyright (©) 2010-2012, 2014 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
*/
/* -------------------------------------------------------------------------- */
#include "material_damage_iterative.hh"
#include "solid_mechanics_model.hh"
__BEGIN_AKANTU__
/* -------------------------------------------------------------------------- */
template<UInt spatial_dimension>
MaterialDamageIterative<spatial_dimension>::MaterialDamageIterative(SolidMechanicsModel & model,
const ID & id) :
Material(model, id),
MaterialDamage<spatial_dimension>(model, id),
Sc("Sc", *this),
equivalent_stress("equivalent_stress", *this),
norm_max_equivalent_stress(0) {
AKANTU_DEBUG_IN();
this->registerParam("Sc", Sc, _pat_parsable, "critical stress threshold");
this->registerParam("prescribed_dam", prescribed_dam, 0.1, _pat_parsable | _pat_modifiable, "increase of damage in every step" );
this->registerParam("dam_threshold", dam_threshold, 0.8, _pat_parsable | _pat_modifiable, "damage threshold at which damage damage will be set to 1" );
this->registerParam("dam_tolerance", dam_tolerance, 0.01, _pat_parsable | _pat_modifiable, "damage tolerance to decide if quadrature point will be damageed" );
this->registerParam("max_damage", max_damage, 0.99999, _pat_parsable | _pat_modifiable, "maximum damage value" );
this->use_previous_stress = true;
this->use_previous_gradu = true;
this->Sc.initialize(1);
this->equivalent_stress.initialize(1);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template<UInt spatial_dimension>
void MaterialDamageIterative<spatial_dimension>::computeNormalizedEquivalentStress(const Array<Real> & grad_u,
ElementType el_type,
GhostType ghost_type) {
AKANTU_DEBUG_IN();
/// Vector to store eigenvalues of current stress tensor
Vector<Real> eigenvalues(spatial_dimension);
Array<Real>::const_iterator<Real> Sc_it = Sc(el_type).begin();
Array<Real>::iterator<Real> equivalent_stress_it = equivalent_stress(el_type).begin();
Array<Real>::const_matrix_iterator grad_u_it = grad_u.begin(spatial_dimension,
spatial_dimension);
Array<Real>::const_matrix_iterator grad_u_end = grad_u.end(spatial_dimension,
spatial_dimension);
Real * dam = this->damage(el_type, ghost_type).storage();
Matrix<Real> sigma(spatial_dimension, spatial_dimension);
for(;grad_u_it != grad_u_end; ++ grad_u_it) {
sigma.clear();
MaterialElastic<spatial_dimension>::computeStressOnQuad(*grad_u_it, sigma, 0.);
computeDamageAndStressOnQuad(sigma,*dam);
/// compute eigenvalues
sigma.eig(eigenvalues);
/// find max eigenvalue and normalize by tensile strength
*equivalent_stress_it = *(std::max_element(eigenvalues.storage(),
eigenvalues.storage() + spatial_dimension)) / *(Sc_it);
++Sc_it;
++equivalent_stress_it;
++dam;
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template<UInt spatial_dimension>
void MaterialDamageIterative<spatial_dimension>::computeAllStresses(GhostType ghost_type) {
AKANTU_DEBUG_IN();
/// reset normalized maximum equivalent stress
if(ghost_type==_not_ghost)
norm_max_equivalent_stress = 0;
MaterialDamage<spatial_dimension>::computeAllStresses(ghost_type);
/// find global Gauss point with highest stress
StaticCommunicator & comm = akantu::StaticCommunicator::getStaticCommunicator();
comm.allReduce(&norm_max_equivalent_stress, 1, _so_max);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template<UInt spatial_dimension>
void MaterialDamageIterative<spatial_dimension>::findMaxNormalizedEquivalentStress(ElementType el_type,
GhostType ghost_type) {
AKANTU_DEBUG_IN();
if(ghost_type==_not_ghost) {
// const Array<Real> & e_stress = equivalent_stress(el_type);
// if (e_stress.begin() != e_stress.end() ) {
// Array<Real>::const_iterator<Real> equivalent_stress_it_max = std::max_element(e_stress.begin(),e_stress.end());
// /// check if max equivalent stress for this element type is greater than the current norm_max_eq_stress
// if (*equivalent_stress_it_max > norm_max_equivalent_stress)
// norm_max_equivalent_stress = *equivalent_stress_it_max;
// }
const Array<Real> & e_stress = equivalent_stress(el_type);
Array<Real>::const_iterator<Real> equivalent_stress_it = e_stress.begin();
Array<Real>::const_iterator<Real> equivalent_stress_end = e_stress.end();
Array<Real> & dam = this->damage(el_type);
Array<Real>::iterator<Real> dam_it = dam.begin();
for (; equivalent_stress_it != equivalent_stress_end; ++equivalent_stress_it, ++dam_it ) {
/// check if max equivalent stress for this element type is greater than the current norm_max_eq_stress and if the element is not already fully damaged
if (*equivalent_stress_it > norm_max_equivalent_stress && *dam_it < max_damage) {
norm_max_equivalent_stress = *equivalent_stress_it;
}
}
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template<UInt spatial_dimension>
void MaterialDamageIterative<spatial_dimension>::computeStress(ElementType el_type,
GhostType ghost_type) {
AKANTU_DEBUG_IN();
MaterialDamage<spatial_dimension>::computeStress(el_type, ghost_type);
Real * dam = this->damage(el_type, ghost_type).storage();
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_BEGIN(el_type, ghost_type);
computeDamageAndStressOnQuad(sigma,*dam);
++dam;
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_END;
computeNormalizedEquivalentStress(this->gradu(el_type, ghost_type), el_type, ghost_type);
norm_max_equivalent_stress = 0;
findMaxNormalizedEquivalentStress(el_type, ghost_type);
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template<UInt spatial_dimension>
UInt MaterialDamageIterative<spatial_dimension>::updateDamage() {
UInt nb_damaged_elements = 0;
AKANTU_DEBUG_ASSERT(prescribed_dam > 0.,
"Your prescribed damage must be greater than zero");
if (norm_max_equivalent_stress >= 1.) {
AKANTU_DEBUG_IN();
GhostType ghost_type = _not_ghost;;
Mesh::type_iterator it = this->model->getFEEngine().getMesh().firstType(spatial_dimension, ghost_type);
Mesh::type_iterator last_type = this->model->getFEEngine().getMesh().lastType(spatial_dimension, ghost_type);
for(; it != last_type; ++it) {
ElementType el_type = *it;
const Array<Real> & e_stress = equivalent_stress(el_type);
Array<Real>::const_iterator<Real> equivalent_stress_it = e_stress.begin();
Array<Real>::const_iterator<Real> equivalent_stress_end = e_stress.end();
Array<Real> & dam = this->damage(el_type);
Array<Real>::iterator<Real> dam_it = dam.begin();
for (; equivalent_stress_it != equivalent_stress_end; ++equivalent_stress_it, ++dam_it ) {
/// check if damage occurs
if (*equivalent_stress_it >= (1-dam_tolerance)*norm_max_equivalent_stress) {
if (*dam_it < dam_threshold)
*dam_it +=prescribed_dam;
else *dam_it = max_damage;
nb_damaged_elements += 1;
}
}
}
}
StaticCommunicator & comm = akantu::StaticCommunicator::getStaticCommunicator();
comm.allReduce(&nb_damaged_elements, 1, _so_sum);
AKANTU_DEBUG_OUT();
return nb_damaged_elements;
}
/* -------------------------------------------------------------------------- */
template<UInt spatial_dimension>
void MaterialDamageIterative<spatial_dimension>::updateEnergiesAfterDamage(ElementType el_type, GhostType ghost_type) {
MaterialDamage<spatial_dimension>::updateEnergies(el_type, ghost_type);
}
/* -------------------------------------------------------------------------- */
INSTANSIATE_MATERIAL(MaterialDamageIterative);
__END_AKANTU__

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