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header_test_slip_laws.cc
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header_test_slip_laws.cc
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/**
* @file header_test_slip_laws.cc
*
* @author Till Junge <till.junge@epfl.ch>
*
* @date 25 Feb 2019
*
* @brief tests for the crystal plasticity slip laws
*
* Copyright © 2019 Till Junge
*
* µSpectre 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, or (at
* your option) any later version.
*
* µSpectre 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
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with µSpectre; see the file COPYING. If not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*
* Additional permission under GNU GPL version 3 section 7
*
* If you modify this Program, or any covered work, by linking or combining it
* with proprietary FFT implementations or numerical libraries, containing parts
* covered by the terms of those libraries' licenses, the licensors of this
* Program grant you additional permission to convey the resulting work.
*/
#include "materials/slip_laws.hh"
#include "materials/materials_toolbox.hh"
#include "tests.hh"
namespace muSpectre {
BOOST_AUTO_TEST_SUITE(Slip_Laws);
BOOST_AUTO_TEST_CASE(tangent_test) {
constexpr Dim_t Dim{2};
constexpr Int NbSlip{1};
using ColArray_t = Eigen::Array<Real, NbSlip, 1>;
using T2_t = Eigen::Matrix<Real, Dim, Dim>;
using T4_t = T4Mat<Real, Dim>;
using SlipLaw_t = SlipLaw<Dim, NbSlip>;
using Hooke_t = MatTB::Hooke<Dim, T2_t, T4_t>;
Real bulk_m{175e9};
Real shear_m{120e9};
Real gamma_dot0{10e-2};
Real m_par{.1};
Real a_par{0};
Real tau_y0{200e6};
Real q_n{1.4};
Real h_0{0e9};
Real delta_t{1e-3};
Real young{MatTB::convert_elastic_modulus<
ElasticModulus::Young, ElasticModulus::Bulk, ElasticModulus::Shear>(
bulk_m, shear_m)};
Real poisson{MatTB::convert_elastic_modulus<
ElasticModulus::Poisson, ElasticModulus::Bulk, ElasticModulus::Shear>(
bulk_m, shear_m)};
T4_t C{Hooke_t::compute_C_T4(young, poisson)};
SlipLaw_t law{gamma_dot0, delta_t, m_par, a_par, q_n, tau_y0, h_0};
T2_t CGe{T2_t::Identity()};
CGe(0, 1) = CGe(0, 1) = .001;
T2_t S_star{2*CGe};
ColArray_t gamma_dot_current{}; gamma_dot_current(0) = 1e-3;
ColArray_t gamma_dot_old{}; gamma_dot_old(0) = 0;
ColArray_t tau_y_current{}; tau_y_current(0) = tau_y0;
std::vector< T2_t,
Eigen::aligned_allocator<T2_t>> SchmidT(1);
SchmidT[0] << 0, 1, 0, 0;
law.prepare_new_time_step(C, CGe, SchmidT);
auto tau_inc{law.compute_tau_inc(CGe, S_star, gamma_dot_current,
gamma_dot_old, SchmidT)};
auto residual{law.compute_residual(gamma_dot_current,
tau_inc,
tau_y_current)};
auto dr_dgamma_dot{
law.compute_dr_dgamma_dot(gamma_dot_current, tau_inc, tau_y_current)};
// compare 1/dr_dgamma to finite difference approximations
auto finite_diff{[&](Real eps) {
return (law.compute_residual(gamma_dot_current + eps, tau_inc,
tau_y_current) -
law.compute_residual(gamma_dot_current - eps, tau_inc,
tau_y_current)) /
(2 * eps);
}};
auto errfun {
[](Real a, Real b) { return std::abs(a - b) / (a + b); }};
constexpr Int NbChecks{10};
Eigen::Array<Real, 1, NbChecks> error{
Eigen::Array<Real, 1, NbChecks>::Zero()};
for (int i{0}; i < NbChecks; ++i) {
Real eps{1. / ipow(10, i + 6)};
Real approx{finite_diff(eps)(0)};
error(i) = errfun(approx, 1. / dr_dgamma_dot(0));
}
std::cout << "errors = " << error << std::endl; }
BOOST_AUTO_TEST_SUITE_END();
} // muSpectre

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