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material_viscoplastic_inline_impl.cc
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Sun, May 12, 01:45

material_viscoplastic_inline_impl.cc
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/**
* @file material_viscoplastic.cc
*
* @author Ramin Aghababaei <ramin.aghababaei@epfl.ch>
*
* @date Tue Jul 09 18:15:37 20130
*
* @brief Implementation of the inline functions of the material viscoplastic
*
* @section LICENSE
*
* Copyright (©) 2010-2011 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 <cmath>
#include "material_viscoplastic.hh"
/* -------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------- */
template<UInt dim>
inline void MaterialViscoPlastic<dim>::computeStressOnQuad(const Matrix<Real> & grad_u,
const Matrix<Real> & previous_grad_u,
Matrix<Real> & sigma,
const Matrix<Real> & previous_sigma,
Matrix<Real> & inelastic_strain,
const Matrix<Real> & previous_inelastic_strain,
Real & iso_hardening) const {
// Infinitesimal plastic
// Compute stress magnitude
Real s = sigma.doubleDot(sigma);
Real sigma_mag=sqrt(s);
// Compute plastic strain increment
Real factor = (this->ts * this->edot0 * pow(sigma_mag, (this->rate - 1.)) /
pow(this->sigma_y + iso_hardening, this->rate));
Matrix<Real> delta_inelastic_strain(sigma);
delta_inelastic_strain *= factor;
// Compute plastic strain increment magnitude
s = delta_inelastic_strain.doubleDot(delta_inelastic_strain);
Real dep_mag = std::sqrt(s);
Matrix<Real> grad_delta_u(grad_u);
grad_delta_u -= previous_grad_u;
// Update stress and plastic strain
Matrix<Real> grad_u_elastic(dim, dim);
grad_u_elastic = grad_delta_u;
grad_u_elastic -= delta_inelastic_strain;
Matrix<Real> sigma_elastic(dim, dim);
MaterialElastic<dim>::computeStressOnQuad(grad_u_elastic, sigma_elastic);
sigma += sigma_elastic;
inelastic_strain += delta_inelastic_strain;
//Update resistance stress
iso_hardening = iso_hardening + this->h * dep_mag;
MaterialPlastic<dim>::computeStressAndInelasticStrainOnQuad(grad_delta_u, sigma, previous_sigma,
inelastic_strain, previous_inelastic_strain,
delta_inelastic_strain);
}
/* -------------------------------------------------------------------------- */
template<UInt dim>
inline void MaterialViscoPlastic<dim>::computeTangentModuliOnQuad(Matrix<Real> & tangent,
const Matrix<Real> & grad_u,
const Matrix<Real> & previous_grad_u,
const Matrix<Real> & sigma_tensor,
const Matrix<Real> & previous_sigma_tensor,
const Real & iso_hardening) const {
UInt cols = tangent.cols();
UInt rows = tangent.rows();
for (UInt m = 0; m < rows; ++m) {
UInt i = VoigtHelper<dim>::vec[m][0];
UInt j = VoigtHelper<dim>::vec[m][1];
for (UInt n = 0; n < cols; ++n) {
UInt k = VoigtHelper<dim>::vec[n][0];
UInt l = VoigtHelper<dim>::vec[n][1];
tangent(m,n) = (i==k) * (j==l) * 2. * this->mu + (i==j) * (k==l) * this->lambda;
tangent(m,n) -= (m==n) * (m>=dim) * this->mu;
}
}
}

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