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rAKA/src/model/solid_mechanics/materials/material_elastic_linear_anisotropic.cc
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material_elastic_linear_anisotropic.cc
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/**
* @file material_elastic_linear_anisotropic.cc
*
* @author Aurelia Isabel Cuba Ramos <aurelia.cubaramos@epfl.ch>
* @author Till Junge <till.junge@epfl.ch>
* @author Enrico Milanese <enrico.milanese@epfl.ch>
* @author Nicolas Richart <nicolas.richart@epfl.ch>
*
* @date creation: Wed Sep 25 2013
* @date last modification: Tue Feb 20 2018
*
* @brief Anisotropic elastic material
*
* @section LICENSE
*
* Copyright (©) 2014-2018 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_linear_anisotropic.hh"
#include "solid_mechanics_model.hh"
#include <algorithm>
#include <sstream>
namespace akantu {
/* -------------------------------------------------------------------------- */
template <UInt dim>
MaterialElasticLinearAnisotropic<dim>::MaterialElasticLinearAnisotropic(
SolidMechanicsModel & model, const ID & id, bool symmetric)
: Material(model, id), rot_mat(dim, dim), Cprime(dim * dim, dim * dim),
C(voigt_h::size, voigt_h::size), eigC(voigt_h::size),
symmetric(symmetric), alpha(0), was_stiffness_assembled(false) {
AKANTU_DEBUG_IN();
this->dir_vecs.push_back(std::make_unique<Vector<Real>>(dim));
(*this->dir_vecs.back())[0] = 1.;
this->registerParam("n1", *(this->dir_vecs.back()), _pat_parsmod,
"Direction of main material axis");
if (dim > 1) {
this->dir_vecs.push_back(std::make_unique<Vector<Real>>(dim));
(*this->dir_vecs.back())[1] = 1.;
this->registerParam("n2", *(this->dir_vecs.back()), _pat_parsmod,
"Direction of secondary material axis");
}
if (dim > 2) {
this->dir_vecs.push_back(std::make_unique<Vector<Real>>(dim));
(*this->dir_vecs.back())[2] = 1.;
this->registerParam("n3", *(this->dir_vecs.back()), _pat_parsmod,
"Direction of tertiary material axis");
}
for (UInt i = 0; i < voigt_h::size; ++i) {
UInt start = 0;
if (this->symmetric) {
start = i;
}
for (UInt j = start; j < voigt_h::size; ++j) {
std::stringstream param("C");
param << "C" << i + 1 << j + 1;
this->registerParam(param.str(), this->Cprime(i, j), Real(0.),
_pat_parsmod, "Coefficient " + param.str());
}
}
this->registerParam("alpha", this->alpha, _pat_parsmod,
"Proportion of viscous stress");
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt dim> void MaterialElasticLinearAnisotropic<dim>::initMaterial() {
AKANTU_DEBUG_IN();
Material::initMaterial();
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt dim>
void MaterialElasticLinearAnisotropic<dim>::updateInternalParameters() {
Material::updateInternalParameters();
if (this->symmetric) {
for (UInt i = 0; i < voigt_h::size; ++i) {
for (UInt j = i + 1; j < voigt_h::size; ++j) {
this->Cprime(j, i) = this->Cprime(i, j);
}
}
}
this->rotateCprime();
this->C.eig(this->eigC);
this->was_stiffness_assembled = false;
}
/* -------------------------------------------------------------------------- */
template <UInt Dim> void MaterialElasticLinearAnisotropic<Dim>::rotateCprime() {
// start by filling the empty parts fo Cprime
UInt diff = Dim * Dim - voigt_h::size;
for (UInt i = voigt_h::size; i < Dim * Dim; ++i) {
for (UInt j = 0; j < Dim * Dim; ++j) {
this->Cprime(i, j) = this->Cprime(i - diff, j);
}
}
for (UInt i = 0; i < Dim * Dim; ++i) {
for (UInt j = voigt_h::size; j < Dim * Dim; ++j) {
this->Cprime(i, j) = this->Cprime(i, j - diff);
}
}
// construction of rotator tensor
// normalise rotation matrix
for (UInt j = 0; j < Dim; ++j) {
Vector<Real> rot_vec = this->rot_mat(j);
rot_vec = *this->dir_vecs[j];
rot_vec.normalize();
}
// make sure the vectors form a right-handed base
Vector<Real> test_axis(3);
Vector<Real> v1(3), v2(3), v3(3, 0.);
if (Dim == 2) {
for (UInt i = 0; i < Dim; ++i) {
v1[i] = this->rot_mat(0, i);
v2[i] = this->rot_mat(1, i);
}
v3.crossProduct(v1, v2);
if (v3.norm() < 8 * std::numeric_limits<Real>::epsilon()) {
AKANTU_ERROR("The axis vectors parallel.");
}
v3.normalize();
} else if (Dim == 3) {
v1 = this->rot_mat(0);
v2 = this->rot_mat(1);
v3 = this->rot_mat(2);
}
test_axis.crossProduct(v1, v2);
test_axis -= v3;
if (test_axis.norm() > 8 * std::numeric_limits<Real>::epsilon()) {
AKANTU_ERROR("The axis vectors do not form a right-handed coordinate "
<< "system. I. e., ||n1 x n2 - n3|| should be zero, but "
<< "it is " << test_axis.norm() << ".");
}
// create the rotator and the reverse rotator
Matrix<Real> rotator(Dim * Dim, Dim * Dim);
Matrix<Real> revrotor(Dim * Dim, Dim * Dim);
for (UInt i = 0; i < Dim; ++i) {
for (UInt j = 0; j < Dim; ++j) {
for (UInt k = 0; k < Dim; ++k) {
for (UInt l = 0; l < Dim; ++l) {
UInt I = voigt_h::mat[i][j];
UInt J = voigt_h::mat[k][l];
rotator(I, J) = this->rot_mat(k, i) * this->rot_mat(l, j);
revrotor(I, J) = this->rot_mat(i, k) * this->rot_mat(j, l);
}
}
}
}
// create the full rotated matrix
Matrix<Real> Cfull(Dim * Dim, Dim * Dim);
Cfull = rotator * Cprime * revrotor;
for (UInt i = 0; i < voigt_h::size; ++i) {
for (UInt j = 0; j < voigt_h::size; ++j) {
this->C(i, j) = Cfull(i, j);
}
}
}
/* -------------------------------------------------------------------------- */
template <UInt dim>
void MaterialElasticLinearAnisotropic<dim>::computeStress(
ElementType el_type, GhostType ghost_type) {
// Wikipedia convention:
// 2*eps_ij (i!=j) = voigt_eps_I
// http://en.wikipedia.org/wiki/Voigt_notation
AKANTU_DEBUG_IN();
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_BEGIN(el_type, ghost_type);
this->computeStressOnQuad(grad_u, sigma);
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_END;
}
/* -------------------------------------------------------------------------- */
template <UInt dim>
void MaterialElasticLinearAnisotropic<dim>::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 dim>
void MaterialElasticLinearAnisotropic<dim>::computePotentialEnergy(
ElementType el_type) {
AKANTU_DEBUG_IN();
AKANTU_DEBUG_ASSERT(!this->finite_deformation,
"finite deformation not possible in material anisotropic "
"(TO BE IMPLEMENTED)");
Array<Real>::scalar_iterator epot =
this->potential_energy(el_type, _not_ghost).begin();
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_BEGIN(el_type, _not_ghost);
computePotentialEnergyOnQuad(grad_u, sigma, *epot);
++epot;
MATERIAL_STRESS_QUADRATURE_POINT_LOOP_END;
AKANTU_DEBUG_OUT();
}
/* -------------------------------------------------------------------------- */
template <UInt dim>
Real MaterialElasticLinearAnisotropic<dim>::getCelerity(
__attribute__((unused)) const Element & element) const {
return std::sqrt(this->eigC(0) / rho);
}
/* -------------------------------------------------------------------------- */
INSTANTIATE_MATERIAL(elastic_anisotropic, MaterialElasticLinearAnisotropic);
} // namespace akantu
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