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test_contact_rigid_no_friction_hertz_3d.cc
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test_contact_rigid_no_friction_hertz_3d.cc
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/**
* @file test_contact_rigid_no_friction_hertz_3d.cc
* @author David Kammer <david.kammer@epfl.ch>
* @date Thu Jan 20 15:50:42 2011
*
* @brief test rigid contact for 3d hertz in explicit
*
* @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 "aka_common.hh"
#include "mesh.hh"
#include "mesh_io.hh"
#include "mesh_io_msh.hh"
#include "mesh_utils.hh"
#include "solid_mechanics_model.hh"
#include "material.hh"
#include "contact.hh"
#include "contact_rigid.hh"
#include "contact_neighbor_structure.hh"
#include "regular_grid_neighbor_structure.hh"
#include "contact_search.hh"
#include "contact_search_explicit.hh"
#ifdef AKANTU_USE_IOHELPER
# include "io_helper.h"
#endif //AKANTU_USE_IOHELPER
using namespace akantu;
int main(int argc, char *argv[])
{
UInt dim = 3;
const ElementType element_type = _tetrahedron_4;
#ifdef AKANTU_USE_IOHELPER
const UInt paraview_type = TETRA1;
#endif //AKANTU_USE_IOHELPER
akantu::initialize(&argc, &argv);
UInt imposing_steps = 1000;
Real max_displacement = -0.01;
UInt damping_steps = 75000;
UInt damping_interval = 50;
Real damping_ratio = 0.99;
UInt max_steps = damping_steps;
/// load mesh
Mesh my_mesh(dim);
MeshIOMSH mesh_io;
mesh_io.read("hertz_3d.msh", my_mesh);
/// build facet connectivity and surface id
MeshUtils::buildFacets(my_mesh,1,0);
MeshUtils::buildSurfaceID(my_mesh);
UInt nb_nodes = my_mesh.getNbNodes();
/// declaration of model
SolidMechanicsModel my_model(my_mesh);
/// model initialization
my_model.initVectors();
// initialize the vectors
memset(my_model.getForce().values, 0, dim*nb_nodes*sizeof(Real));
memset(my_model.getVelocity().values, 0, dim*nb_nodes*sizeof(Real));
memset(my_model.getAcceleration().values, 0, dim*nb_nodes*sizeof(Real));
memset(my_model.getDisplacement().values, 0, dim*nb_nodes*sizeof(Real));
memset(my_model.getBoundary().values, false, dim*nb_nodes*sizeof(bool));
my_model.initExplicit();
my_model.initModel();
my_model.readMaterials("material.dat");
my_model.initMaterials();
UInt nb_element = my_model.getFEM().getMesh().getNbElement(element_type);
Real time_step = my_model.getStableTimeStep();
my_model.setTimeStep(time_step/10.);
my_model.assembleMassLumped();
Surface impactor = 0;
Surface rigid_body_surface = 1;
Surface master = 2;
// modify surface id
UInt nb_surfaces = my_mesh.getNbSurfaces();
my_mesh.setNbSurfaces(++nb_surfaces);
ElementType surface_element_type = my_mesh.getFacetElementType(element_type);
UInt nb_surface_element = my_model.getFEM().getMesh().getNbElement(surface_element_type);
UInt * surface_id_val = my_mesh.getSurfaceID(surface_element_type).values;
for(UInt i=0; i < nb_surface_element; ++i) {
if (surface_id_val[i] == rigid_body_surface) {
Real barycenter[dim];
Real * barycenter_p = &barycenter[0];
my_mesh.getBarycenter(i,surface_element_type,barycenter_p);
if(barycenter_p[1] > -1.001) {
surface_id_val[i] = master;
}
}
}
/// contact declaration
Contact * contact = Contact::newContact(my_model,
_ct_rigid,
_cst_expli,
_cnst_regular_grid);
ContactRigid * my_contact = dynamic_cast<ContactRigid *>(contact);
my_contact->initContact(false);
my_contact->addMasterSurface(master);
my_contact->addImpactorSurfaceToMasterSurface(impactor, master);
my_model.updateCurrentPosition(); // neighbor structure uses current position for init
my_contact->initNeighborStructure(master);
my_contact->initSearch(); // does nothing so far
// boundary conditions
Vector<UInt> * top_nodes = new Vector<UInt>(0, 1);
Real * coordinates = my_mesh.getNodes().values;
Real * displacement = my_model.getDisplacement().values;
bool * boundary = my_model.getBoundary().values;
UInt * surface_to_nodes_offset = my_contact->getSurfaceToNodesOffset().values;
UInt * surface_to_nodes = my_contact->getSurfaceToNodes().values;
// symetry boundary conditions
for(UInt n = surface_to_nodes_offset[impactor]; n < surface_to_nodes_offset[impactor+1]; ++n) {
UInt node = surface_to_nodes[n];
Real x_coord = coordinates[node*dim];
Real y_coord = coordinates[node*dim + 1];
Real z_coord = coordinates[node*dim + 2];
if (x_coord < 0.00001)
boundary[node*dim] = true;
if (z_coord < 0.00001)
boundary[node*dim+2] = true;
if (y_coord > -0.00001) {
boundary[node*dim + 1] = true;
top_nodes->push_back(node);
}
}
// ground boundary conditions
for(UInt n = surface_to_nodes_offset[rigid_body_surface]; n < surface_to_nodes_offset[rigid_body_surface+1]; ++n) {
UInt node = surface_to_nodes[n];
Real y_coord = coordinates[node*dim + 1];
if (y_coord < -1.19999) {
boundary[node*dim] = true;
boundary[node*dim + 1] = true;
boundary[node*dim + 2] = true;
}
}
UInt * top_nodes_val = top_nodes->values;
Real * velocity_val = my_model.getVelocity().values;
my_model.updateResidual();
#ifdef AKANTU_USE_IOHELPER
/// initialize the paraview output
DumperParaview dumper;
dumper.SetMode(TEXT);
dumper.SetPoints(my_model.getFEM().getMesh().getNodes().values, dim, nb_nodes, "coordinates_3d");
dumper.SetConnectivity((int *)my_model.getFEM().getMesh().getConnectivity(element_type).values,
paraview_type, nb_element, C_MODE);
dumper.AddNodeDataField(my_model.getDisplacement().values,
dim, "displacements");
dumper.AddNodeDataField(my_model.getVelocity().values, dim, "velocity");
dumper.AddNodeDataField(my_model.getResidual().values, dim, "force");
dumper.AddNodeDataField(my_model.getForce().values, dim, "applied_force");
dumper.AddElemDataField(my_model.getMaterial(0).getStrain(element_type).values, dim*dim, "strain");
dumper.AddElemDataField(my_model.getMaterial(0).getStress(element_type).values, dim*dim, "stress");
dumper.SetEmbeddedValue("displacements", 1);
dumper.SetEmbeddedValue("applied_force", 1);
dumper.SetPrefix("paraview/hertz_3d/");
dumper.Init();
dumper.Dump();
#endif //AKANTU_USE_IOHELPER
std::ofstream hertz;
hertz.open("output_files/hertz_3d.csv");
hertz << "%id,ftop,fcont,zone" << std::endl;
std::ofstream energy;
energy.open("output_files/hertz_3d_energy.csv");
energy << "%id,kin,pot,tot" << std::endl;
/* ------------------------------------------------------------------------ */
/* Main loop */
/* ------------------------------------------------------------------------ */
for(UInt s = 1; s <= max_steps; ++s) {
if(s % 10 == 0) std::cout << "passing step " << s << "/" << max_steps << std::endl;
/*
if(s % 250 == 0){
my_model.updateCurrentPosition();
my_contact->updateContact();
}
*/
if(s <= imposing_steps) {
Real current_displacement = max_displacement/(static_cast<Real>(imposing_steps))*s;
for(UInt n=0; n<top_nodes->getSize(); ++n) {
UInt node = top_nodes_val[n];
displacement[node*dim + 1] = current_displacement;
}
}
// damp velocity in order to find equilibrium
if(s < damping_steps && s%damping_interval == 0) {
for (UInt i=0; i < nb_nodes; ++i) {
for (UInt j=0; j < dim; ++j)
velocity_val[i*dim + j] *= damping_ratio;
}
}
my_model.explicitPred();
my_model.initializeUpdateResidualData();
my_contact->solveContact();
my_model.updateResidual(false);
my_contact->avoidAdhesion();
// find the total force applied at the imposed displacement surface (top)
Real * residual = my_model.getResidual().values;
Real top_force = 0.;
for(UInt n=0; n<top_nodes->getSize(); ++n) {
UInt node = top_nodes_val[n];
top_force += residual[node*dim + 1];
}
// find index of master surface in impactors_information
ContactRigid::SurfaceToImpactInfoMap::const_iterator it_imp;
it_imp = my_contact->getImpactorsInformation().find(master);
// find the total contact force and contact area
ContactRigid::ImpactorInformationPerMaster * imp_info = it_imp->second;
UInt * active_imp_nodes_val = imp_info->active_impactor_nodes->values;
Real * current_position = my_model.getCurrentPosition().values;
Real contact_force = 0.;
Real contact_zone = 0.;
for (UInt i = 0; i < imp_info->active_impactor_nodes->getSize(); ++i) {
UInt node = active_imp_nodes_val[i];
contact_force += residual[node*dim + 1];
contact_zone = std::max(contact_zone, current_position[node*dim]);
}
hertz << s << "," << top_force << "," << contact_force << "," << contact_zone << std::endl;
// test if correct result is found
if((s == max_steps) && (std::abs(contact_force + 7.29637e+07) > 1e2)) {
std::cout << "contact_force = " << contact_force << " but should be = -7.29637e+07" << std::endl;
return EXIT_FAILURE;
}
my_model.updateAcceleration();
my_model.explicitCorr();
Real epot = my_model.getPotentialEnergy();
Real ekin = my_model.getKineticEnergy();
energy << s << "," << ekin << "," << epot << "," << ekin+epot << std::endl;
#ifdef AKANTU_USE_IOHELPER
if(s % 100 == 0) dumper.Dump();
#endif //AKANTU_USE_IOHELPER
}
hertz.close();
energy.close();
delete my_contact;
delete top_nodes;
finalize();
return EXIT_SUCCESS;
}

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