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test_contact_2d_expli.cc
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test_contact_2d_expli.cc
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/**
* @file test_contact_2d_expli.cc
* @author Leonardo Snozzi <leonardo.snozzi@epfl.ch>
* @date Fri Nov 26 07:43:47 2010
*
* @brief test explicit DCR contact algorithm for 2d
*
* @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 <limits>
#include <fstream>
/* -------------------------------------------------------------------------- */
#include "aka_common.hh"
#include "mesh.hh"
#include "mesh_io.hh"
#include "mesh_io_msh.hh"
#include "solid_mechanics_model.hh"
#include "material.hh"
#include "contact.hh"
#include "io_helper.h"
/* -------------------------------------------------------------------------- */
#ifdef AKANTU_USE_IOHELPER
#include "io_helper.h"
#endif //AKANTU_USE_IOHELPER
#define NORMAL_PRESSURE -1.e6
using namespace akantu;
static void reduceGap(const SolidMechanicsModel & model, const Real threshold, const Real gap);
static void setBoundaryConditions(SolidMechanicsModel & model);
void my_force(double * coord, double *T);
static void reduceVelocities(const SolidMechanicsModel & model, const Real ratio);
static void initParaview(SolidMechanicsModel & model);
Real y_min, y_max;
DumperParaview dumper;
int main(int argc, char *argv[])
{
UInt spatial_dimension = 2;
UInt max_steps = 30000;
Real time_factor = 0.2;
Mesh mesh(spatial_dimension);
MeshIOMSH mesh_io;
mesh_io.read("squares.msh", mesh);
SolidMechanicsModel * model = new SolidMechanicsModel(mesh);
/// get two squares closer
// reduceGap(*model, 0.05, 1.e-6);
UInt nb_nodes = model->getFEM().getMesh().getNbNodes();
UInt nb_elements = model->getFEM().getMesh().getNbElement(_triangle_3);
/// model initialization
model->initVectors();
model->readMaterials("materials.dat");
model->initMaterials();
model->initModel();
std::cout << model->getMaterial(0) << std::endl;
model->assembleMassLumped();
/// set vectors to zero
memset(model->getForce().values, 0,
spatial_dimension*nb_nodes*sizeof(Real));
memset(model->getVelocity().values, 0,
spatial_dimension*nb_nodes*sizeof(Real));
memset(model->getAcceleration().values, 0,
spatial_dimension*nb_nodes*sizeof(Real));
memset(model->getDisplacement().values, 0,
spatial_dimension*nb_nodes*sizeof(Real));
memset(model->getResidual().values, 0,
spatial_dimension*nb_nodes*sizeof(Real));
memset(model->getMaterial(0).getStrain(_triangle_3).values, 0,
spatial_dimension*spatial_dimension*nb_elements*sizeof(Real));
memset(model->getMaterial(0).getStress(_triangle_3).values, 0,
spatial_dimension*spatial_dimension*nb_elements*sizeof(Real));
/// Paraview Helper
#ifdef AKANTU_USE_IOHELPER
initParaview(*model);
#endif //AKANTU_USE_IOHELPER
Real time_step = model->getStableTimeStep() * time_factor;
std::cout << "Time Step = " << time_step << "s" << std::endl;
model->setTimeStep(time_step);
/// set boundary conditions
setBoundaryConditions(*model);
/// define and initialize contact
Contact * my_contact = Contact::newContact(*model,
_ct_2d_expli,
_cst_2d_expli,
_cnst_2d_grid);
my_contact->initContact(true);
my_contact->setFrictionCoefficient(0.);
my_contact->initNeighborStructure();
my_contact->initSearch();
for (UInt s = 0; s < max_steps; ++s) {
model->explicitPred();
model->updateCurrentPosition();
my_contact->solveContact();
model->updateResidual();
model->updateAcceleration();
model->explicitCorr();
if(s % 200 == 0)
dumper.Dump();
if(s%100 == 0 && s>499)
reduceVelocities(*model, 0.95);
if(s % 500 == 0) std::cout << "passing step " << s << "/" << max_steps << std::endl;
}
delete my_contact;
delete model;
finalize();
return EXIT_SUCCESS;
}
/* -------------------------------------------------------------------------- */
static void reduceGap(const SolidMechanicsModel & model, const Real threshold, const Real gap) {
UInt nb_nodes = model.getFEM().getMesh().getNbNodes();
Real * coord = model.getFEM().getMesh().getNodes().values;
Real y_top = HUGE_VAL, y_bot = -HUGE_VAL;
for (UInt n = 0; n < nb_nodes; ++n) {
if (coord[2*n+1] > threshold) {
if(coord[2*n+1] < y_top)
y_top = coord[2*n+1];
}
else {
if (coord[2*n+1] > y_bot)
y_bot = coord[2*n+1];
}
}
Real delta = y_top - y_bot - gap;
/// move all nodes belonging to the top cube
for (UInt n = 0; n < nb_nodes; ++n) {
if (coord[2*n+1] > threshold)
coord[2*n+1] -= delta;
}
}
/* -------------------------------------------------------------------------- */
static void setBoundaryConditions(SolidMechanicsModel & model) {
UInt nb_nodes = model.getFEM().getMesh().getNbNodes();
Real * coord = model.getFEM().getMesh().getNodes().values;
for (UInt n = 0; n < nb_nodes; ++n) {
if (coord[2*n+1] > y_max)
y_max = coord[2*n+1];
if (coord[2*n+1] < y_min)
y_min = coord[2*n+1];
}
FEM & b_fem = model.getFEMBoundary();
b_fem.initShapeFunctions();
b_fem.computeNormalsOnQuadPoints();
bool * id = model.getBoundary().values;
memset(id, 0, 2*nb_nodes*sizeof(bool));
std::cout << "Nodes ";
for (UInt i = 0; i < nb_nodes; ++i) {
if (coord[2*i+1] < y_min + 1.e-5) {
id[2*i+1] = true;
std::cout << " " << i << " ";
}
}
std::cout << "are blocked" << std::endl;
model.computeForcesFromFunction(my_force, _bft_stress);
}
/* -------------------------------------------------------------------------- */
void my_force(double * coord, double *T) {
memset(T, 0, 4*sizeof(double));
if(*(coord+1) > y_max-1.e-5)
T[3] = NORMAL_PRESSURE;
}
/* -------------------------------------------------------------------------- */
/// artificial damping of velocities in order to reach a global static equilibrium
static void reduceVelocities(const SolidMechanicsModel & model, const Real ratio)
{
UInt nb_nodes = model.getFEM().getMesh().getNbNodes();
Real * velocities = model.getVelocity().values;
if(ratio>1.) {
fprintf(stderr,"**error** in Reduce_Velocities ratio bigger than 1!\n");
exit(-1);
}
for(UInt i =0; i<nb_nodes; i++) {
velocities[2*i] *= ratio;
velocities[2*i+1] *= ratio;
}
}
/* -------------------------------------------------------------------------- */
static void initParaview(SolidMechanicsModel & model)
{
UInt spatial_dimension = model.getSpatialDimension();
UInt nb_nodes = model.getFEM().getMesh().getNbNodes();
UInt nb_elements = model.getFEM().getMesh().getNbElement(_triangle_3);
dumper.SetMode(TEXT);
dumper.SetPoints(model.getFEM().getMesh().getNodes().values,
spatial_dimension, nb_nodes, "coordinates");
dumper.SetConnectivity((int *)model.getFEM().getMesh().getConnectivity(_triangle_3).values,
TRIANGLE1, nb_elements, C_MODE);
dumper.AddNodeDataField(model.getDisplacement().values,
spatial_dimension, "displacements");
dumper.AddNodeDataField(model.getVelocity().values,
spatial_dimension, "velocity");
dumper.AddNodeDataField(model.getResidual().values,
spatial_dimension, "force");
dumper.AddElemDataField(model.getMaterial(0).getStrain(_triangle_3).values,
spatial_dimension*spatial_dimension, "strain");
dumper.AddElemDataField(model.getMaterial(0).getStress(_triangle_3).values,
spatial_dimension*spatial_dimension, "stress");
dumper.SetEmbeddedValue("displacements", 1);
dumper.SetPrefix("paraview/");
dumper.Init();
dumper.Dump();
}

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