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Stablized radius update, added WFM, added outputs

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This commit is contained in:
William Zunker
2025-03-26 10:43:51 -04:00
parent 285baf27b5
commit 9d01ac2caf
7 changed files with 236 additions and 40 deletions
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42
src/GRANULAR/fix_granular_mdr.cpp
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@ -38,6 +38,10 @@
#include "update.h" #include "update.h"
#include "variable.h" #include "variable.h"
// wzunker
#include "csv_writer.h"
#include <sstream>
using namespace LAMMPS_NS; using namespace LAMMPS_NS;
using namespace Granular_NS; using namespace Granular_NS;
using namespace Granular_MDR_NS; using namespace Granular_MDR_NS;
@ -45,7 +49,7 @@ using namespace FixConst;
using MathConst::MY_PI; using MathConst::MY_PI;
static constexpr double EPSILON = 1e-16; static constexpr double EPSILON = 1e-16;
static constexpr double OVERLAP_LIMIT = 0.75; static constexpr double OVERLAP_LIMIT = 0.95;
enum { COMM_1, COMM_2 }; enum { COMM_1, COMM_2 };
@ -85,7 +89,7 @@ void FixGranularMDR::post_constructor()
modify->add_fix( modify->add_fix(
fmt::format("{} all property/atom d_Ro d_Vcaps d_Vgeo d_Velas d_eps_bar d_dRnumerator " fmt::format("{} all property/atom d_Ro d_Vcaps d_Vgeo d_Velas d_eps_bar d_dRnumerator "
"d_dRdenominator d_Acon0 d_Acon1 d_Atot d_Atot_sum d_ddelta_bar d_psi " "d_dRdenominator d_Acon0 d_Acon1 d_Atot d_Atot_sum d_ddelta_bar d_psi "
"d_history_setup_flag d_sigmaxx d_sigmayy d_sigmazz ghost yes", "d_history_setup_flag d_sigmaxx d_sigmayy d_sigmazz d_dRavg ghost yes",
id_fix)); id_fix));
index_Ro = atom->find_custom("Ro", tmp1, tmp2); index_Ro = atom->find_custom("Ro", tmp1, tmp2);
@ -105,6 +109,7 @@ void FixGranularMDR::post_constructor()
index_sigmaxx = atom->find_custom("sigmaxx", tmp1, tmp2); index_sigmaxx = atom->find_custom("sigmaxx", tmp1, tmp2);
index_sigmayy = atom->find_custom("sigmayy", tmp1, tmp2); index_sigmayy = atom->find_custom("sigmayy", tmp1, tmp2);
index_sigmazz = atom->find_custom("sigmazz", tmp1, tmp2); index_sigmazz = atom->find_custom("sigmazz", tmp1, tmp2);
index_dRavg = atom->find_custom("dRavg", tmp1, tmp2);
} }
/* ---------------------------------------------------------------------- */ /* ---------------------------------------------------------------------- */
@ -208,6 +213,7 @@ void FixGranularMDR::pre_force(int)
double *sigmayy = atom->dvector[index_sigmayy]; double *sigmayy = atom->dvector[index_sigmayy];
double *sigmazz = atom->dvector[index_sigmazz]; double *sigmazz = atom->dvector[index_sigmazz];
double *history_setup_flag = atom->dvector[index_history_setup_flag]; double *history_setup_flag = atom->dvector[index_history_setup_flag];
double *dRavg = atom->dvector[index_dRavg];
int new_atom; int new_atom;
int nlocal = atom->nlocal; int nlocal = atom->nlocal;
@ -250,10 +256,35 @@ void FixGranularMDR::pre_force(int)
psi[i] = (Atot[i] - Acon1[i]) / Atot[i]; psi[i] = (Atot[i] - Acon1[i]) / Atot[i];
if (psi_b_coeff < psi[i]) { if (psi_b_coeff < psi[i]) {
const double dR = MAX(dRnumerator[i] / (dRdenominator[i] - 4.0 * MY_PI * pow(R, 2.0)), 0.0); double w_confinement;
if ((radius[i] + dR) < (1.5 * Ro[i])) radius[i] += dR; ( psi[i] > 0.1 ) ? w_confinement = 1.0/(1.0 + exp(-75.0*(psi[i]-0.2))) : w_confinement = 0.0;
const double dR = MAX(dRnumerator[i] / (dRdenominator[i] - 4.0 * MY_PI * pow(R, 2.0))*w_confinement, 0.0);
const double N_window = 10.0;
if (dR > 0.0) dRavg[i] += (dR - dRavg[i]) / N_window;
if (((radius[i] + dR) < (1.5 * Ro[i])) && (dR > 0.0)) radius[i] += dRavg[i];
//(dR + dRavg[i])/2.0;
//dRavg[i] = (dR + dRavg[i])/2.0;
//// wzunker
//const double dRdenominatorTrue = (dRdenominator[i] - 4.0 * MY_PI * pow(R, 2.0));
//if (i == 0) {
// CSVWriter csvWriter("/Users/willzunker/simulations/lammps/bulk_response/compression_sleeve/dR_parameters.csv");
// std::stringstream rowDataStream;
// rowDataStream << std::scientific << std::setprecision(8); // Set the format and precision
// rowDataStream << dRnumerator[i] << ", " << dRdenominator[i] << ", " << dRavg[i] << ", " << R << ", " << dRdenominatorTrue << ", " << lmp->update->ntimestep;
// std::string rowData = rowDataStream.str();
// csvWriter.writeRow(rowData);
//}
} }
Acon0[i] = Acon1[i]; Acon0[i] = Acon1[i];
// wzunker
//const double dR_tmp = MAX(dRnumerator[i] / (dRdenominator[i] - 4.0 * MY_PI * pow(R, 2.0)), 0.0);
//printf("i = %d, psi_b = %f, psi = %f, Atot = %f, Acon = %f, dRnumerator = %f, dRdenominator = %f, R = %f, dR = %f \n", i, psi_b_coeff, psi[i], Atot[i], Acon1[i], dRnumerator[i], dRdenominator[i],radius[i],dR_tmp);
} }
comm_stage = COMM_1; comm_stage = COMM_1;
@ -510,6 +541,9 @@ void FixGranularMDR::calculate_contact_penalty()
"(e.g. increase the skin distance)."); "(e.g. increase the skin distance).");
pjk[0] += 1.0 / (1.0 + std::exp(-50.0 * (alpha / MY_PI - 0.5))); pjk[0] += 1.0 / (1.0 + std::exp(-50.0 * (alpha / MY_PI - 0.5)));
// wzunker
//printf("i = %d, j = %d, k = %d, pij = %f, pik = %f, pjk = %f \n", i, j, k, pij[0], pik[0], pjk[0]);
} }
} }
} }

3
src/GRANULAR/fix_granular_mdr.h
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@ -97,8 +97,7 @@ class FixGranularMDR : public Fix {
int index_sigmayy; // yy-component of the stress tensor, not necessary forforce calculation int index_sigmayy; // yy-component of the stress tensor, not necessary forforce calculation
int index_sigmazz; // zz-component of the stress tensor, not necessary forforce calculation int index_sigmazz; // zz-component of the stress tensor, not necessary forforce calculation
int index_history_setup_flag; // flag to check if history variables have beeninitialized int index_history_setup_flag; // flag to check if history variables have beeninitialized
int index_contacts; // total contacts on particle int index_dRavg; // total contacts on particle
int index_adhesive_length; // total length of adhesive contact on a particle
}; };
} // namespace LAMMPS_NS } // namespace LAMMPS_NS

10
src/GRANULAR/gran_sub_mod_damping.cpp
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@ -18,6 +18,8 @@
#include "math_special.h" #include "math_special.h"
#include "math_const.h" #include "math_const.h"
#include "style_gran_sub_mod.h" // IWYU pragma: keep
#include <cmath> #include <cmath>
using namespace LAMMPS_NS; using namespace LAMMPS_NS;
@ -74,8 +76,12 @@ GranSubModDampingVelocity::GranSubModDampingVelocity(GranularModel *gm, LAMMPS *
double GranSubModDampingVelocity::calculate_forces() double GranSubModDampingVelocity::calculate_forces()
{ {
damp_prefactor = damp; if (gm->normal_model->name == "mdr") {
return -damp_prefactor * gm->vnnr; return 0.0;
} else {
damp_prefactor = damp;
return -damp_prefactor * gm->vnnr;
}
} }
/* ---------------------------------------------------------------------- /* ----------------------------------------------------------------------

189
src/GRANULAR/gran_sub_mod_normal.cpp
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@ -26,6 +26,9 @@
#include <iomanip> #include <iomanip>
#include <sstream> #include <sstream>
// wzunker
#include "csv_writer.h"
using namespace LAMMPS_NS; using namespace LAMMPS_NS;
using namespace Granular_NS; using namespace Granular_NS;
using namespace MathConst; using namespace MathConst;
@ -47,7 +50,7 @@ static constexpr int MDR_MAX_IT = 100; // Newton-Raphs
static constexpr double MDR_EPSILON1 = 1e-10; // Newton-Raphson for MDR static constexpr double MDR_EPSILON1 = 1e-10; // Newton-Raphson for MDR
static constexpr double MDR_EPSILON2 = 1e-16; // Newton-Raphson for MDR static constexpr double MDR_EPSILON2 = 1e-16; // Newton-Raphson for MDR
static constexpr double MDR_EPSILON3 = 1e-20; // For precision checks static constexpr double MDR_EPSILON3 = 1e-20; // For precision checks
static constexpr double MDR_OVERLAP_LIMIT = 0.75; // Maximum contact overlap for MDR static constexpr double MDR_OVERLAP_LIMIT = 0.95; // Maximum contact overlap for MDR
static const char cite_mdr[] = static const char cite_mdr[] =
"MDR contact model command: (i) https://doi.org/10.1016/j.jmps.2023.105492 || (ii) https://doi.org/10.1016/j.jmps.2023.105493 || (iii) https://doi.org/10.31224/4289\n\n" "MDR contact model command: (i) https://doi.org/10.1016/j.jmps.2023.105492 || (ii) https://doi.org/10.1016/j.jmps.2023.105493 || (iii) https://doi.org/10.31224/4289\n\n"
@ -472,14 +475,16 @@ void GranSubModNormalMDR::coeffs_to_local()
Y = coeffs[2]; // yield stress Y = coeffs[2]; // yield stress
gamma = coeffs[3]; // effective surface energy gamma = coeffs[3]; // effective surface energy
psi_b = coeffs[4]; // bulk response trigger based on ratio of remaining free area: A_{free}/A_{total} psi_b = coeffs[4]; // bulk response trigger based on ratio of remaining free area: A_{free}/A_{total}
CoR = coeffs[5]; // coefficent of restitution //CoR = coeffs[5]; // coefficent of restitution
damp = coeffs[5]; // coefficent of restitution
if (E <= 0.0) error->all(FLERR, "Illegal MDR normal model, Young's modulus must be greater than 0"); if (E <= 0.0) error->all(FLERR, "Illegal MDR normal model, Young's modulus must be greater than 0");
if (nu < 0.0 || nu > 0.5) error->all(FLERR, "Illegal MDR normal model, Poisson's ratio must be between 0 and 0.5"); if (nu < 0.0 || nu > 0.5) error->all(FLERR, "Illegal MDR normal model, Poisson's ratio must be between 0 and 0.5");
if (Y < 0.0) error->all(FLERR, "Illegal MDR normal model, yield stress must be greater than or equal to 0"); if (Y < 0.0) error->all(FLERR, "Illegal MDR normal model, yield stress must be greater than or equal to 0");
if (gamma < 0.0) error->all(FLERR, "Illegal MDR normal model, effective surface energy must be greater than or equal to 0"); if (gamma < 0.0) error->all(FLERR, "Illegal MDR normal model, effective surface energy must be greater than or equal to 0");
if (psi_b < 0.0 || psi_b > 1.0) error->all(FLERR, "Illegal MDR normal model, psi_b must be between 0 and 1.0"); if (psi_b < 0.0 || psi_b > 1.0) error->all(FLERR, "Illegal MDR normal model, psi_b must be between 0 and 1.0");
if (CoR < 0.0 || CoR > 1.0) error->all(FLERR, "Illegal MDR normal model, coefficent of restitution must be between 0 and 1.0"); //if (CoR < 0.0 || CoR > 1.0) error->all(FLERR, "Illegal MDR normal model, coefficent of restitution must be between 0 and 1.0");
if (damp < 0.0) error->all(FLERR, "Illegal MDR normal model, damping coefficent must be greater than 1");
G = E / (2.0 * (1.0 + nu)); // shear modulus G = E / (2.0 * (1.0 + nu)); // shear modulus
kappa = E / (3.0 * (1.0 - 2.0 * nu)); // bulk modulus kappa = E / (3.0 * (1.0 - 2.0 * nu)); // bulk modulus
@ -490,6 +495,7 @@ void GranSubModNormalMDR::coeffs_to_local()
Eeffinv = 1.0 / Eeff; Eeffinv = 1.0 / Eeff;
Eeffsq = Eeff * Eeff; Eeffsq = Eeff * Eeff;
Eeffsqinv = Eeffinv * Eeffinv; Eeffsqinv = Eeffinv * Eeffinv;
Eeff2particle = 0.5 * Eeff;
gammasq = gamma * gamma; gammasq = gamma * gamma;
gamma3 = gammasq * gamma; gamma3 = gammasq * gamma;
@ -528,6 +534,7 @@ void GranSubModNormalMDR::init()
index_sigmaxx = atom->find_custom("sigmaxx", tmp1, tmp2); // xx-component of the stress tensor, not necessary for force calculation index_sigmaxx = atom->find_custom("sigmaxx", tmp1, tmp2); // xx-component of the stress tensor, not necessary for force calculation
index_sigmayy = atom->find_custom("sigmayy", tmp1, tmp2); // yy-component of the stress tensor, not necessary for force calculation index_sigmayy = atom->find_custom("sigmayy", tmp1, tmp2); // yy-component of the stress tensor, not necessary for force calculation
index_sigmazz = atom->find_custom("sigmazz", tmp1, tmp2); // zz-component of the stress tensor, not necessary for force calculation index_sigmazz = atom->find_custom("sigmazz", tmp1, tmp2); // zz-component of the stress tensor, not necessary for force calculation
index_dRavg = atom->find_custom("dRavg", tmp1, tmp2); // radius update increment
} }
/* ---------------------------------------------------------------------- */ /* ---------------------------------------------------------------------- */
@ -566,6 +573,7 @@ double GranSubModNormalMDR::calculate_forces()
double *sigmaxx = atom->dvector[index_sigmaxx]; double *sigmaxx = atom->dvector[index_sigmaxx];
double *sigmayy = atom->dvector[index_sigmayy]; double *sigmayy = atom->dvector[index_sigmayy];
double *sigmazz = atom->dvector[index_sigmazz]; double *sigmazz = atom->dvector[index_sigmazz];
double *dRavg = atom->dvector[index_dRavg];
const int itag_true = atom->tag[gm->i]; // true i particle tag const int itag_true = atom->tag[gm->i]; // true i particle tag
const int jtag_true = atom->tag[gm->j]; // true j particle tag const int jtag_true = atom->tag[gm->j]; // true j particle tag
@ -579,6 +587,7 @@ double GranSubModNormalMDR::calculate_forces()
double F1 = 0.0; // force on contact side 1 double F1 = 0.0; // force on contact side 1
double delta = gm->delta; // apparent overlap double delta = gm->delta; // apparent overlap
double Ac_avg = 0.0; // average contact area across both sides double Ac_avg = 0.0; // average contact area across both sides
double a_damp = 0.0; // damping contact radius
double *history = & gm->history[history_index]; // load in all history variables double *history = & gm->history[history_index]; // load in all history variables
int history_update = gm->history_update; int history_update = gm->history_update;
@ -596,6 +605,11 @@ double GranSubModNormalMDR::calculate_forces()
if (gm->delta >= *deltamax_offset) *deltamax_offset = gm->delta; if (gm->delta >= *deltamax_offset) *deltamax_offset = gm->delta;
double deltamax = *deltamax_offset; double deltamax = *deltamax_offset;
//wzunker
double F_MDR0;
double F_BULK0;
double F_MDR1;
double F_BULK1;
for (int contactSide = 0; contactSide < 2; contactSide++) { for (int contactSide = 0; contactSide < 2; contactSide++) {
@ -607,7 +621,7 @@ double GranSubModNormalMDR::calculate_forces()
// displacement partitioning only necessary for particle-particle contact // displacement partitioning only necessary for particle-particle contact
// itag and jtag persist after neighbor list builds, use tags to compare to match // itag and jtag persist after neighbor list builds, use tags to compare to match
// contact history variables consistently across steps for a particle pair. // contact history variables consistently across steps for a particle pair.
if ((contactSide == 0 && itag_true > jtag_true) || (contactSide != 0 && itag_true < jtag_true)) { if ((contactSide == 0 && itag_true > jtag_true) || (contactSide != 0 && itag_true < jtag_true)) {
gm->i = i_true; gm->i = i_true;
gm->j = j_true; gm->j = j_true;
@ -804,8 +818,10 @@ double GranSubModNormalMDR::calculate_forces()
F_MDR = calculate_nonadhesive_mdr_force(deltae1D, Ainv, Eeff, A, B); F_MDR = calculate_nonadhesive_mdr_force(deltae1D, Ainv, Eeff, A, B);
} }
if (std::isnan(F_MDR)) if (std::isnan(F_MDR)) {
printf("itag = %d, jtag = %d \n", itag_true, jtag_true);
error->one(FLERR, "F_MDR is NaN, case 1: no tensile springs"); error->one(FLERR, "F_MDR is NaN, case 1: no tensile springs");
}
if (history_update) *aAdh_offset = a_fac * a_na; if (history_update) *aAdh_offset = a_fac * a_na;
} else { } else {
@ -861,15 +877,20 @@ double GranSubModNormalMDR::calculate_forces()
} }
aAdh = aAdh_tmp; aAdh = aAdh_tmp;
g_aAdh = A * 0.5 - A * Binv * sqrt(Bsq * 0.25 - pow(aAdh, 2)); if (aAdh < acrit) {
g_aAdh = round_up_negative_epsilon(g_aAdh); aAdh = 0.0;
F_MDR = 0.0;
} else {
g_aAdh = A * 0.5 - A * Binv * sqrt(Bsq * 0.25 - pow(aAdh, 2));
g_aAdh = round_up_negative_epsilon(g_aAdh);
const double deltaeAdh = g_aAdh; const double deltaeAdh = g_aAdh;
const double F_na = calculate_nonadhesive_mdr_force(deltaeAdh, Ainv, Eeff, A, B); const double F_na = calculate_nonadhesive_mdr_force(deltaeAdh, Ainv, Eeff, A, B);
const double F_Adhes = 2.0 * Eeff * (deltae1D - deltaeAdh) * aAdh; const double F_Adhes = 2.0 * Eeff * (deltae1D - deltaeAdh) * aAdh;
F_MDR = F_na + F_Adhes; F_MDR = F_na + F_Adhes;
if (std::isnan(F_MDR)) if (std::isnan(F_MDR))
error->one(FLERR, "F_MDR is NaN, case 3: tensile springs exceed critical length"); error->one(FLERR, "F_MDR is NaN, case 3: tensile springs exceed critical length");
}
} }
if (history_update) *aAdh_offset = aAdh; if (history_update) *aAdh_offset = aAdh;
} }
@ -891,13 +912,22 @@ double GranSubModNormalMDR::calculate_forces()
} }
Ac_avg += wij * Ac; Ac_avg += wij * Ac;
// wzunker damping contact area related things
(gamma > 0.0) ? a_damp += aAdh : a_damp += a_na;
// bulk force calculation // bulk force calculation
double F_BULK; double F_BULK;
(delta_BULK <= 0.0) ? F_BULK = 0.0 : F_BULK = (1.0 / Vgeo[i]) * Acon0[i] * delta_BULK * kappa * Ac; (delta_BULK <= 0.0) ? F_BULK = 0.0 : F_BULK = (1.0 / Vgeo[i]) * Acon0[i] * delta_BULK * kappa * Ac;
// force-magnifier
// total force calculation // total force calculation
(contactSide == 0) ? F0 = F_MDR + F_BULK : F1 = F_MDR + F_BULK; (contactSide == 0) ? F0 = F_MDR + F_BULK : F1 = F_MDR + F_BULK;
// wzunker
(contactSide == 0) ? F_MDR0 = F_MDR : F_MDR1 = F_MDR;
(contactSide == 0) ? F_BULK0 = F_BULK : F_BULK1 = F_BULK;
if (history_update) { if (history_update) {
// mean surface displacement calculation // mean surface displacement calculation
*Ac_offset = wij * Ac; *Ac_offset = wij * Ac;
@ -921,6 +951,32 @@ double GranSubModNormalMDR::calculate_forces()
dRnumerator[i] -= Vo * (eps_bar_contact - *eps_bar_offset); dRnumerator[i] -= Vo * (eps_bar_contact - *eps_bar_offset);
dRnumerator[i] -= wij * MY_PI * ddeltao * (2 * deltao * Ro - pow(deltao, 2) + pow(R, 2) - pow(Ro, 2)); dRnumerator[i] -= wij * MY_PI * ddeltao * (2 * deltao * Ro - pow(deltao, 2) + pow(R, 2) - pow(Ro, 2));
dRdenominator[i] += wij * 2.0 * MY_PI * R * (deltao + R - Ro); dRdenominator[i] += wij * 2.0 * MY_PI * R * (deltao + R - Ro);
// wzunker
//if (gm->contact_type == PAIR && i == 0) {
// CSVWriter csvWriter("/Users/willzunker/simulations/lammps/bulk_response/compression_sleeve/dR_parameters_0.csv");
// std::stringstream rowDataStream;
// rowDataStream << std::scientific << std::setprecision(8); // Set the format and precision
// rowDataStream << wij << ", " << dRnumerator[i] << ", " << dRdenominator[i] << ", " << eps_bar_contact << ", " << *eps_bar_offset << ", " << ddeltao << ", " << deltao << ", " << R << ", " << Fntmp << ", " << lmp->update->ntimestep;
// std::string rowData = rowDataStream.str();
// csvWriter.writeRow(rowData);
//}
//
//if (gm->contact_type == PAIR && i == 1) {
// CSVWriter csvWriter("/Users/willzunker/simulations/lammps/bulk_response/compression_sleeve/dR_parameters_1.csv");
// std::stringstream rowDataStream;
// rowDataStream << std::scientific << std::setprecision(8); // Set the format and precision
// rowDataStream << wij << ", " << dRnumerator[i] << ", " << dRdenominator[i] << ", " << eps_bar_contact << ", " << *eps_bar_offset << ", " << ddeltao << ", " << deltao << ", " << R << ", " << Fntmp << ", " << lmp->update->ntimestep;
// std::string rowData = rowDataStream.str();
// csvWriter.writeRow(rowData);
//}
// wzunker
//if (gm->contact_type == PAIR) {
// printf("i = %d, j = %d, contact_type = %d, dRnumerator = %f, dRdenominator = %f, eps_bar_contact = %f, eps_bar_offset = %f, wij = %f, ddelto = %f, deltao = %f, R = %f, Fntmp = %f \n", i, gm->j, gm->contact_type, dRnumerator[i], dRdenominator[i], eps_bar_contact, *eps_bar_offset, wij, ddeltao, deltao, R, Fntmp);
//}
} }
if (history_update) { if (history_update) {
@ -944,31 +1000,106 @@ double GranSubModNormalMDR::calculate_forces()
const double wij = MAX(1.0 - pij, 0.0); const double wij = MAX(1.0 - pij, 0.0);
// assign final force // assign final force
double damp_prefactor;
if (gm->contact_type != PAIR) { if (gm->contact_type != PAIR) {
F = wij * F0; a_damp = a_damp/2.0;
damp_prefactor = 0.5*sqrt(gm->meff * 2.0 * Eeff2particle * a_damp);
double *deltao_offset = &history[DELTAO_0];
const double wfm = std::exp(10.7*(*deltao_offset)/Rinitial[gm->i] - 10.0) + 1.0; // wall force magnifier
//const double wfm = 1.0;
F = wij * F0 * wfm;
} else { } else {
damp_prefactor = 0.5*sqrt(gm->meff * 2.0 * Eeff * a_damp);
F = wij * (F0 + F1) * 0.5; F = wij * (F0 + F1) * 0.5;
} }
// calculate damping force // calculate damping force
if (F > 0.0) { //if (F > 0.0) {
double Eeff2; // double Eeff2;
double Reff2; // double Reff2;
if (gm->contact_type == PAIR) { // if (gm->contact_type == PAIR) {
Eeff2 = E / (2.0 * (1.0 - pow(nu, 2))); // Eeff2 = E / (2.0 * (1.0 - pow(nu, 2)));
Reff2 = 1.0 / ((1.0 / gm->radi + 1.0 / gm->radj)); // Reff2 = 1.0 / ((1.0 / gm->radi + 1.0 / gm->radj));
} else { // } else {
Eeff2 = E / (1.0 - pow(nu, 2)); // Eeff2 = E / (1.0 - pow(nu, 2));
Reff2 = gm->radi; // Reff2 = gm->radi;
} // }
const double kn = Eeff2 * Reff2; // const double kn = Eeff2 * Reff2;
const double beta = -log(CoR) / sqrt(pow(log(CoR), 2) + PISQ); // const double beta = -log(CoR) / sqrt(pow(log(CoR), 2) + PISQ);
const double damp_prefactor = beta * sqrt(gm->meff * kn); // const double damp_prefactor = beta * sqrt(gm->meff * kn);
const double F_DAMP = -damp_prefactor * gm->vnnr; // const double F_DAMP = -damp_prefactor * gm->vnnr;
//
// F += wij * F_DAMP;
//}
F += wij * F_DAMP; // calculate damping force
if (F > 0.0) F += -wij * damp * gm->vnnr;
//F += -wij * damp_prefactor * gm->vnnr;
//printf("i = %d, j = %d, wij = %f, damp = %f, vnnr = %e, F_DAMP = %e \n", gm->i, gm->j, wij, damp, gm->vnnr, -wij * damp * gm->vnnr);
// wzunker
double *delta_offset_0 = &history[DELTA_0];
double *delta_offset_1 = &history[DELTA_0 + 1];
const double delta0 = *delta_offset_0;
const double delta1 = *delta_offset_1;
double *delta_BULK_offset_0 = &history[DELTA_BULK_0];
double *delta_BULK_offset_1 = &history[DELTA_BULK_0 + 1];
const double deltaBULK0 = *delta_BULK_offset_0;
const double deltaBULK1 = *delta_BULK_offset_1;
double *aAdh_offset_0 = &history[AADH_0];
double *aAdh_offset_1 = &history[AADH_0 + 1];
const double aAdh0 = *aAdh_offset_0;
const double aAdh1 = *aAdh_offset_1;
double *Ac_offset_0 = &history[AC_0];
double *Ac_offset_1 = &history[AC_0 + 1];
const double Ac0 = *Ac_offset_0;
const double Ac1 = *Ac_offset_1;
double F_DAMP = -wij * damp * gm->vnnr;
const double i_0 = 0;
const double i_1 = 1;
double psi_0;
double psi_1;
double Acon_0;
double Acon_1;
double Vgeo_0;
double Vgeo_1;
if (itag_true == i_0) {
psi_0 = psi[gm->i];
psi_1 = psi[gm->j];
Acon_0 = Acon0[gm->i];
Acon_1 = Acon0[gm->j];
Vgeo_0 = Vgeo[gm->i];
Vgeo_1 = Vgeo[gm->j];
} else {
psi_0 = psi[gm->j];
psi_1 = psi[gm->i];
Acon_0 = Acon0[gm->j];
Acon_1 = Acon0[gm->i];
Vgeo_0 = Vgeo[gm->j];
Vgeo_1 = Vgeo[gm->i];
} }
//if ( (itag_true == i_0 && jtag_true == i_1) || (itag_true == i_1 && jtag_true == i_0) ) {
// CSVWriter csvWriter("/Users/willzunker/simulations/lammps/avicel_tableting/avicel_tableting_pair_info.csv");
// std::stringstream rowDataStream;
// rowDataStream << std::scientific << std::setprecision(8); // Set the format and precision
// rowDataStream << itag_true << ", " << jtag_true << ", " << delta0 << ", " << delta1 << ", " << F0 << ", " << F1 << ", " << F << ", " << gm->radi << ", " << gm->radj << ", " << wij << ", " << psi_0 << ", " << psi_1 << ", " << aAdh0 << ", " << aAdh1 << ", " << Ac0 << ", " << Ac1 << ", " << F_MDR0 << ", " << F_MDR1 << ", " << F_BULK0 << ", " << F_BULK1 << ", " << deltaBULK0 << ", " << deltaBULK1 << ", " << Acon_0 << ", " << Acon_1 << ", " << Vgeo_0 << ", " << Vgeo_1 << ", " << kappa << ", " << lmp->update->ntimestep;
// std::string rowData = rowDataStream.str();
// csvWriter.writeRow(rowData);
//}
//if ( (gm->contact_type == PAIR) ) {
// CSVWriter csvWriter("/Users/willzunker/simulations/lammps/bulk_response/sticky/pair_info.csv");
// std::stringstream rowDataStream;
// rowDataStream << std::scientific << std::setprecision(8); // Set the format and precision
// rowDataStream << itag_true << ", " << jtag_true << ", " << delta0 << ", " << delta1 << ", " << F0 << ", " << F1 << ", " << F << ", " << gm->radi << ", " << gm->radj << ", " << wij << ", " << psi_0 << ", " << psi_1 << ", " << aAdh0 << ", " << aAdh1 << ", " << Ac0 << ", " << Ac1 << ", " << F_MDR0 << ", " << F_MDR1 << ", " << F_BULK0 << ", " << F_BULK1 << ", " << deltaBULK0 << ", " << deltaBULK1 << ", " << Acon_0 << ", " << Acon_1 << ", " << Vgeo_0 << ", " << Vgeo_1 << ", " << kappa << ", " << F_DAMP << ", " << gm->vnnr << ", " << delta << ", " << lmp->update->ntimestep;
// std::string rowData = rowDataStream.str();
// csvWriter.writeRow(rowData);
//}
return F; return F;
} }

3
src/GRANULAR/gran_sub_mod_normal.h
View File

@ -147,7 +147,7 @@ namespace Granular_NS {
protected: protected:
double G, kappa, Eeff; // derived coeffs double G, kappa, Eeff; // derived coeffs
double Eeffsq, Eeffinv, Eeffsqinv; double Eeffsq, Eeffinv, Eeffsqinv, Eeff2particle;
double gammasq, gamma3, gamma4; double gammasq, gamma3, gamma4;
int warn_flag; int warn_flag;
@ -155,6 +155,7 @@ namespace Granular_NS {
int index_Ro, index_Vgeo, index_Velas, index_Vcaps, index_eps_bar, index_dRnumerator; int index_Ro, index_Vgeo, index_Velas, index_Vcaps, index_eps_bar, index_dRnumerator;
int index_dRdenominator, index_Acon0, index_Acon1, index_Atot, index_Atot_sum, index_ddelta_bar; int index_dRdenominator, index_Acon0, index_Acon1, index_Atot, index_Atot_sum, index_ddelta_bar;
int index_psi, index_sigmaxx, index_sigmayy, index_sigmazz, index_contacts, index_adhesive_length; int index_psi, index_sigmaxx, index_sigmayy, index_sigmazz, index_contacts, index_adhesive_length;
int index_dRavg;
int fix_mdr_flag; int fix_mdr_flag;
char *id_fix; char *id_fix;

4
src/GRANULAR/granular_model.cpp
View File

@ -251,8 +251,8 @@ void GranularModel::init()
// Must have valid normal, damping, and tangential models // Must have valid normal, damping, and tangential models
if (normal_model->name == "none") error->all(FLERR, "Must specify normal granular model"); if (normal_model->name == "none") error->all(FLERR, "Must specify normal granular model");
if (normal_model->name == "mdr") { if (normal_model->name == "mdr") {
if (damping_model->name != "none") //if (damping_model->name != "none")
error->all(FLERR, "MDR require 'none' damping model. To damp, specify a coefficient of restitution < 1."); //error->all(FLERR, "MDR require 'none' damping model. To damp, specify a coefficient of restitution < 1.");
} else { } else {
if (damping_model->name == "none") error->all(FLERR, "Must specify damping granular model"); if (damping_model->name == "none") error->all(FLERR, "Must specify damping granular model");
} }

25
src/csv_writer.h Normal file
View File

@ -0,0 +1,25 @@
#include <iostream>
#include <fstream>
#include <string>
class CSVWriter {
public:
CSVWriter(const std::string& filename) : filename_(filename) {}
void writeRow(const std::string& data) {
std::ofstream file;
// Use the append mode to add data to the end of the file if it exists
file.open(filename_, std::ios::out | std::ios::app);
if (!file.is_open()) {
std::cerr << "Failed to open file: " << filename_ << std::endl;
return;
}
file << data << std::endl;
file.close();
}
private:
std::string filename_;
};