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test_structural_mechanics_model_bernoulli_beam_dynamics.cc
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test_structural_mechanics_model_bernoulli_beam_dynamics.cc
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/**
* @file test_structural_mechanics_model_bernoulli_beam_dynamics.cc
*
* @author Sébastien Hartmann <sebastien.hartmann@epfl.ch>
*
* @date creation: Mon Jul 07 2014
* @date last modification: Sun Oct 19 2014
*
* @brief Test for _bernouilli_beam in dynamic
*
* @section LICENSE
*
* Copyright (©) 2014, 2015 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 <limits>
#include <fstream>
/* -------------------------------------------------------------------------- */
#include "aka_common.hh"
#include "mesh.hh"
#include "mesh_io.hh"
#include "mesh_io_msh_struct.hh"
#include "structural_mechanics_model.hh"
#include "material.hh"
#include <iostream>
using namespace akantu;
/* -------------------------------------------------------------------------- */
#define TYPE _bernoulli_beam_2
static Real analytical_solution(Real time, Real L, Real rho, Real E, Real A, Real I, Real F) {
Real omega = M_PI*M_PI/L/L*sqrt(E*I/rho);
Real sum = 0.;
UInt i=5;
for(UInt n=1; n <= i; n +=2) {
sum += (1. - cos(n*n*omega*time))/pow(n, 4);
}
return 2.*F*pow(L, 3)/pow(M_PI, 4)/E/I*sum;
}
//load
const Real F = 0.5e4;
/* -------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------- */
int main(int argc, char *argv[]){
initialize(argc, argv);
Mesh beams(2);
debug::setDebugLevel(dblWarning);
const ElementType type = _bernoulli_beam_2;
/* -------------------------------------------------------------------------- */
// Mesh
UInt nb_element = 8;
UInt nb_nodes = nb_element + 1;
Real total_length = 10.;
Real length = total_length/nb_element;
Real heigth = 1.;
Array<Real> & nodes = const_cast<Array<Real> &>(beams.getNodes());
nodes.resize(nb_nodes);
beams.addConnectivityType(type);
Array<UInt> &connectivity = const_cast<Array<UInt> &>(beams.getConnectivity(type));
connectivity.resize(nb_element);
beams.initNormals();
Array<Real> & normals = const_cast<Array<Real> &>(beams.getNormals(type));
normals.resize(nb_element);
for (UInt i = 0; i < nb_nodes; ++i){
nodes(i,0) = i * length;
nodes(i,1) = 0;
}
for (UInt i = 0; i < nb_element; ++i){
connectivity(i,0) = i;
connectivity(i,1) = i+1;
}
/* -------------------------------------------------------------------------- */
// Materials
StructuralMechanicsModel model(beams);
StructuralMaterial mat1;
mat1.E = 120e6;
mat1.rho = 1000;
mat1.A = heigth;
mat1.I = heigth*heigth*heigth/12;
model.addMaterial(mat1);
/* -------------------------------------------------------------------------- */
// Forces
// model.initFull();
model.initFull(StructuralMechanicsModelOptions(_implicit_dynamic));
const Array<Real> &position = beams.getNodes();
Array<Real> &forces = model.getForce();
Array<Real> &displacement = model.getDisplacement();
Array<bool> &boundary = model.getBlockedDOFs();
UInt node_to_print = -1;
forces.clear();
displacement.clear();
// boundary.clear();
//model.getElementMaterial(type)(i,0) = 0;
//model.getElementMaterial(type)(i,0) = 1;
for (UInt i = 0; i < nb_element; ++i) {
model.getElementMaterial(type)(i,0) = 0;
}
for (UInt n =0; n<nb_nodes; ++n){
Real x = position(n, 0);
// Real y = position(n, 1);
if (Math::are_float_equal(x, total_length/2.)){
forces(n,1) = F;
node_to_print = n;
}
}
std::ofstream pos;
pos.open("position.csv");
if(!pos.good()) {
std::cerr << "Cannot open file" << std::endl;
exit(EXIT_FAILURE);
}
pos << "id,time,position,solution" << std::endl;
// model.computeForcesFromFunction<type>(load, _bft_traction)
/* -------------------------------------------------------------------------- */
// Boundary conditions
// true ~ displacement is blocked
boundary(0,0) = true;
boundary(0,1) = true;
boundary(nb_nodes-1,1) = true;
/* -------------------------------------------------------------------------- */
// "Solve"
Real time = 0;
model.assembleStiffnessMatrix();
model.assembleMass();
model.dump();
model.getStiffnessMatrix().saveMatrix("K.mtx");
model.getMassMatrix().saveMatrix("M.mt");
Real time_step = 1e-4;
model.setTimeStep(time_step);
std::cout << "Time" << " | " << "Mid-Span Displacement" << std::endl;
/// time loop
for (UInt s = 1; time < 0.64; ++s) {
model.solveStep<_scm_newton_raphson_tangent, _scc_increment>(1e-12, 1000);
pos << s << "," << time << "," << displacement(node_to_print, 1) << "," << analytical_solution(s*time_step, total_length, mat1.rho, mat1.E, mat1.A, mat1.I, F) << std::endl;
// pos << s << "," << time << "," << displacement(node_to_print, 1) << "," << analytical_solution(s*time_step) << std::endl;
time += time_step;
if(s % 100 == 0)
std::cout << time << " | " << displacement(node_to_print, 1) << std::endl;
model.dump();
}
pos.close();
finalize();
return EXIT_SUCCESS;
}

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