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material_elastic.cc
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/**
* @file material_elastic.cc
*
* @author Lucas Frerot <lucas.frerot@epfl.ch>
* @author Daniel Pino Muñoz <daniel.pinomunoz@epfl.ch>
* @author Nicolas Richart <nicolas.richart@epfl.ch>
* @author Marco Vocialta <marco.vocialta@epfl.ch>
*
* @date creation: Fri Jun 18 2010
* @date last modification: Mon Jan 29 2018
*
* @brief Specialization of the material class for the elastic material
*
* @section LICENSE
*
* Copyright (©) 2010-2018 EPFL (Ecole Polytechnique Fédérale de Lausanne)
* Laboratory (LSMS - Laboratoire de Simulation en Mécanique des Solides)
*
* Akantu is free software: you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License as published by the Free
* Software Foundation, either version 3 of the License, or (at your option) any
* later version.
*
* Akantu is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
* details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with Akantu. If not, see <http://www.gnu.org/licenses/>.
*
*/
/* -------------------------------------------------------------------------- */
#include "material_elastic.hh"
#include "solid_mechanics_model.hh"
/* -------------------------------------------------------------------------- */
namespace akantu {
/* -------------------------------------------------------------------------- */
template <UInt dim>
MaterialElastic<dim>::MaterialElastic(SolidMechanicsModel & model,
const ID & id)
: Parent(model, id), was_stiffness_assembled(false) {
AKANTU_DEBUG_IN();
this->initialize();
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt dim>
MaterialElastic<dim>::MaterialElastic(SolidMechanicsModel & model,
__attribute__((unused)) UInt a_dim,
const Mesh & mesh, FEEngine & fe_engine,
const ID & id)
: Parent(model, dim, mesh, fe_engine, id), was_stiffness_assembled(false) {
AKANTU_DEBUG_IN();
this->initialize();
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt dim> void MaterialElastic<dim>::initialize() {
this->registerParam("lambda", lambda, _pat_readable,
"First Lamé coefficient");
this->registerParam("mu", mu, _pat_readable, "Second Lamé coefficient");
this->registerParam("kapa", kpa, _pat_readable, "Bulk coefficient");
}
/* -------------------------------------------------------------------------- */
template <UInt dim> void MaterialElastic<dim>::initMaterial() {
AKANTU_DEBUG_IN();
Parent::initMaterial();
if (dim == 1)
this->nu = 0.;
this->updateInternalParameters();
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt dim> void MaterialElastic<dim>::updateInternalParameters() {
MaterialThermal<dim>::updateInternalParameters();
this->lambda = this->nu * this->E / ((1 + this->nu) * (1 - 2 * this->nu));
this->mu = this->E / (2 * (1 + this->nu));
this->kpa = this->lambda + 2. / 3. * this->mu;
this->was_stiffness_assembled = false;
}
/* -------------------------------------------------------------------------- */
template <> void MaterialElastic<2>::updateInternalParameters() {
MaterialThermal<2>::updateInternalParameters();
this->lambda = this->nu * this->E / ((1 + this->nu) * (1 - 2 * this->nu));
this->mu = this->E / (2 * (1 + this->nu));
if (this->plane_stress)
this->lambda = this->nu * this->E / ((1 + this->nu) * (1 - this->nu));
this->kpa = this->lambda + 2. / 3. * this->mu;
this->was_stiffness_assembled = false;
}
/* -------------------------------------------------------------------------- */
template <UInt spatial_dimension>
void MaterialElastic<spatial_dimension>::computeStress(ElementType el_type,
GhostType ghost_type) {
AKANTU_DEBUG_IN();
Parent::computeStress(el_type, ghost_type);
Array<Real>::const_scalar_iterator sigma_th_it =
this->sigma_th(el_type, ghost_type).begin();
if (!this->finite_deformation) {
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_BEGIN(el_type, ghost_type);
const Real & sigma_th = *sigma_th_it;
this->computeStressOnQuad(grad_u, sigma, sigma_th);
++sigma_th_it;
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_END;
} else {
/// finite gradus
Matrix<Real> E(spatial_dimension, spatial_dimension);
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_BEGIN(el_type, ghost_type);
/// compute E
this->template gradUToGreenStrain<spatial_dimension>(grad_u, E);
const Real & sigma_th = *sigma_th_it;
/// compute second Piola-Kirchhoff stress tensor
this->computeStressOnQuad(E, sigma, sigma_th);
++sigma_th_it;
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_END;
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt spatial_dimension>
void MaterialElastic<spatial_dimension>::computeTangentModuli(
const ElementType & el_type, Array<Real> & tangent_matrix,
GhostType ghost_type) {
AKANTU_DEBUG_IN();
MATERIAL_TANGENT_QUADRATURE_POINT_LOOP_BEGIN(tangent_matrix);
this->computeTangentModuliOnQuad(tangent);
MATERIAL_TANGENT_QUADRATURE_POINT_LOOP_END;
this->was_stiffness_assembled = true;
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt spatial_dimension>
Real MaterialElastic<spatial_dimension>::getPushWaveSpeed(
const Element &) const {
return sqrt((lambda + 2 * mu) / this->rho);
}
/* -------------------------------------------------------------------------- */
template <UInt spatial_dimension>
Real MaterialElastic<spatial_dimension>::getShearWaveSpeed(
const Element &) const {
return sqrt(mu / this->rho);
}
/* -------------------------------------------------------------------------- */
template <UInt spatial_dimension>
void MaterialElastic<spatial_dimension>::computePotentialEnergy(
ElementType el_type) {
AKANTU_DEBUG_IN();
// MaterialThermal<dim>::computePotentialEnergy(ElementType)
// needs to be implemented
// MaterialThermal<spatial_dimension>::computePotentialEnergy(el_type);
auto epot = this->potential_energy(el_type, _not_ghost).begin();
if (!this->finite_deformation) {
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_BEGIN(el_type, _not_ghost);
this->computePotentialEnergyOnQuad(grad_u, sigma, *epot);
++epot;
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_END;
} else {
Matrix<Real> E(spatial_dimension, spatial_dimension);
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_BEGIN(el_type, _not_ghost);
this->template gradUToGreenStrain<spatial_dimension>(grad_u, E);
this->computePotentialEnergyOnQuad(E, sigma, *epot);
++epot;
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_END;
}
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt spatial_dimension>
void MaterialElastic<spatial_dimension>::computePotentialEnergyByElement(
ElementType type, UInt index, Vector<Real> & epot_on_quad_points) {
auto gradu_it = this->gradu(type).begin(spatial_dimension, spatial_dimension);
auto gradu_end =
this->gradu(type).begin(spatial_dimension, spatial_dimension);
auto stress_it =
this->stress(type).begin(spatial_dimension, spatial_dimension);
if (this->finite_deformation)
stress_it = this->piola_kirchhoff_2(type).begin(spatial_dimension,
spatial_dimension);
UInt nb_quadrature_points = this->fem.getNbIntegrationPoints(type);
gradu_it += index * nb_quadrature_points;
gradu_end += (index + 1) * nb_quadrature_points;
stress_it += index * nb_quadrature_points;
Real * epot_quad = epot_on_quad_points.storage();
Matrix<Real> grad_u(spatial_dimension, spatial_dimension);
for (; gradu_it != gradu_end; ++gradu_it, ++stress_it, ++epot_quad) {
if (this->finite_deformation)
this->template gradUToGreenStrain<spatial_dimension>(*gradu_it, grad_u);
else
grad_u.copy(*gradu_it);
this->computePotentialEnergyOnQuad(grad_u, *stress_it, *epot_quad);
}
}
/* -------------------------------------------------------------------------- */
template <>
Real MaterialElastic<1>::getPushWaveSpeed(const Element & /*element*/) const {
return std::sqrt(this->E / this->rho);
}
template <>
Real MaterialElastic<1>::getShearWaveSpeed(const Element & /*element*/) const {
AKANTU_EXCEPTION("There is no shear wave speed in 1D");
}
/* -------------------------------------------------------------------------- */
INSTANTIATE_MATERIAL(elastic, MaterialElastic);
} // akantu

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