/* ---------------------------------------------------------------------- This is the ██╗ ██╗ ██████╗ ██████╗ ██████╗ ██╗ ██╗████████╗███████╗ ██║ ██║██╔════╝ ██╔════╝ ██╔════╝ ██║ ██║╚══██╔══╝██╔════╝ ██║ ██║██║ ███╗██║ ███╗██║ ███╗███████║ ██║ ███████╗ ██║ ██║██║ ██║██║ ██║██║ ██║██╔══██║ ██║ ╚════██║ ███████╗██║╚██████╔╝╚██████╔╝╚██████╔╝██║ ██║ ██║ ███████║ ╚══════╝╚═╝ ╚═════╝ ╚═════╝ ╚═════╝ ╚═╝ ╚═╝ ╚═╝ ╚══════╝® DEM simulation engine, released by DCS Computing Gmbh, Linz, Austria http://www.dcs-computing.com, office@dcs-computing.com LIGGGHTS® is part of CFDEM®project: http://www.liggghts.com | http://www.cfdem.com Core developer and main author: Christoph Kloss, christoph.kloss@dcs-computing.com LIGGGHTS® is open-source, distributed under the terms of the GNU Public License, version 2 or later. It 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. You should have received a copy of the GNU General Public License along with LIGGGHTS®. If not, see http://www.gnu.org/licenses . See also top-level README and LICENSE files. LIGGGHTS® and CFDEM® are registered trade marks of DCS Computing GmbH, the producer of the LIGGGHTS® software and the CFDEM®coupling software See http://www.cfdem.com/terms-trademark-policy for details. ------------------------------------------------------------------------- Contributing author and copyright for this file: Contributing authors: Rahul Mohanty (University of Edinburgh, P&G) ------------------------------------------------------------------------- */ #ifdef TANGENTIAL_MODEL TANGENTIAL_MODEL(TANGENTIAL_LUDING,tan_luding,4) #else #ifndef TANGENTIAL_MODEL_LUDING_H_ #define TANGENTIAL_MODEL_LUDING_H_ #include "contact_models.h" #include "tangential_model_base.h" #include #include "update.h" #include "global_properties.h" #include "atom.h" namespace LIGGGHTS { namespace ContactModels { template<> class TangentialModel : public TangentialModelBase { double ** coeffFrict; double ** coeffMu; double ** coeffFricVisc; double ** kT2kcMax; int history_offset; int kc_offset; int fo_offset; public: TangentialModel(LAMMPS * lmp, IContactHistorySetup * hsetup,class ContactModelBase *c) : TangentialModelBase(lmp, hsetup, c), coeffFrict(NULL), coeffMu(NULL), coeffFricVisc(NULL), kT2kcMax(NULL), heating(false), heating_track(false), // kc_Stiffness(NULL), cmb(c) { history_offset = hsetup->add_history_value("shearx", "1"); hsetup->add_history_value("sheary", "1"); hsetup->add_history_value("shearz", "1"); kc_offset = cmb->get_history_offset("kc_offset"); fo_offset = cmb->get_history_offset("fo_offset"); } void registerSettings(Settings& settings){ settings.registerOnOff("heating_tangential_history",heating,false); settings.registerOnOff("heating_tracking",heating_track,false); //TODO error->one(FLERR,"TODO here also check if right surface model used"); } void postSettings(IContactHistorySetup * hsetup, ContactModelBase *cmb) {} void connectToProperties(PropertyRegistry & registry) { registry.registerProperty("coeffFrict", &MODEL_PARAMS::createCoeffFrict); registry.registerProperty("coeffMu", &MODEL_PARAMS::createCoeffMu); registry.registerProperty("coeffFricVisc", &MODEL_PARAMS::createCoeffFricVisc); registry.registerProperty("kT2kcMax", &MODEL_PARAMS::createCoeffFrictionStiffness); registry.connect("coeffFrict", coeffFrict,"tangential_model tan_luding"); registry.connect("coeffMu", coeffMu,"tangential_model tan_luding"); registry.connect("coeffFricVisc", coeffFricVisc,"tangential_model tan_luding"); registry.connect("kT2kcMax", kT2kcMax,"tangential_model tan_luding"); } void surfacesIntersect(const SurfacesIntersectData & sidata, ForceData & i_forces, ForceData & j_forces) { const double enx = sidata.en[0]; const double eny = sidata.en[1]; const double enz = sidata.en[2]; const double deltan = sidata.deltan; double k_t = sidata.kt; double kt = k_t * kT2kcMax[sidata.itype][sidata.jtype]; // tangential stiffness based on the ratio input // shear history effects if(sidata.contact_flags) *sidata.contact_flags |= CONTACT_TANGENTIAL_MODEL; double * const shear = &sidata.contact_history[history_offset]; // double * const K_adh = &sidata.contact_history[kc_Stiffness]; if (sidata.shearupdate && sidata.computeflag) { const double dt = update->dt; shear[0] += sidata.vtr1 * dt; shear[1] += sidata.vtr2 * dt; shear[2] += sidata.vtr3 * dt; // rotate shear displacements double rsht = shear[0]*enx + shear[1]*eny + shear[2]*enz; shear[0] -= rsht * enx; shear[1] -= rsht * eny; shear[2] -= rsht * enz; } const double shrmag = sqrt(shear[0]*shear[0] + shear[1]*shear[1] + shear[2]*shear[2]); const double xmuS = coeffFrict[sidata.itype][sidata.jtype]; //coefficient of sliding friction const double xmuD = xmuS * coeffMu[sidata.itype][sidata.jtype]; //coefficient of dynamic friction const double gammat = sidata.gammat * coeffFricVisc[sidata.itype][sidata.jtype]; // error->one(FLERR,"model-specific data not allows in contact_interface.h, do use contact history instead"); const double kc = sidata.contact_history[kc_offset];//K_adh;//0.;//sidata.kc; const double f_adh = sidata.contact_history[fo_offset]; double Ft1 = -(kt * shear[0]); double Ft2 = -(kt * shear[1]); double Ft3 = -(kt * shear[2]); // rescale frictional displacements and forces if needed const double Ft_shear = kt * shrmag; const double Ft_frictionS = xmuS * (fabs(sidata.Fn + kc * deltan - f_adh)); // energy loss from sliding or damping if (Ft_shear > Ft_frictionS) { if (shrmag != 0.0) { const double Ft_frictionD = xmuD * (fabs(sidata.Fn + kc * deltan - f_adh)); const double ratio = Ft_frictionD/Ft_shear; Ft1 *= ratio; Ft2 *= ratio; Ft3 *= ratio; shear[0] = -(Ft1) /kt; shear[1] = -(Ft2) /kt; shear[2] = -(Ft3) /kt; } else Ft1 = Ft2 = Ft3 = 0.0; } else { Ft1 -= (gammat*sidata.vtr1); Ft2 -= (gammat*sidata.vtr2); Ft3 -= (gammat*sidata.vtr3); } // forces & torques const double tor1 = eny * Ft3 - enz * Ft2; const double tor2 = enz * Ft1 - enx * Ft3; const double tor3 = enx * Ft2 - eny * Ft1; #ifdef NONSPHERICAL_ACTIVE_FLAG double torque_i[3]; if(sidata.is_non_spherical) { double xci[3]; double Ft_i[3] = { Ft1, Ft2, Ft3 }; vectorSubtract3D(sidata.contact_point, atom->x[sidata.i], xci); vectorCross3D(xci, Ft_i, torque_i); } else { torque_i[0] = -sidata.cri * tor1; torque_i[1] = -sidata.cri * tor2; torque_i[2] = -sidata.cri * tor3; } #endif // return resulting forces if(sidata.is_wall) { const double area_ratio = sidata.area_ratio; i_forces.delta_F[0] += Ft1 * area_ratio; i_forces.delta_F[1] += Ft2 * area_ratio; i_forces.delta_F[2] += Ft3 * area_ratio; #ifdef NONSPHERICAL_ACTIVE_FLAG i_forces.delta_torque[0] += torque_i[0] * area_ratio; i_forces.delta_torque[1] += torque_i[1] * area_ratio; i_forces.delta_torque[2] += torque_i[2] * area_ratio; #else i_forces.delta_torque[0] += -sidata.cri * tor1 * area_ratio; i_forces.delta_torque[1] += -sidata.cri * tor2 * area_ratio; i_forces.delta_torque[2] += -sidata.cri * tor3 * area_ratio; #endif } else { i_forces.delta_F[0] += Ft1; i_forces.delta_F[1] += Ft2; i_forces.delta_F[2] += Ft3; j_forces.delta_F[0] += -Ft1; j_forces.delta_F[1] += -Ft2; j_forces.delta_F[2] += -Ft3; #ifdef NONSPHERICAL_ACTIVE_FLAG double torque_j[3]; if(sidata.is_non_spherical) { double xcj[3]; vectorSubtract3D(sidata.contact_point, atom->x[sidata.j], xcj); double Ft_j[3] = { -Ft1, -Ft2, -Ft3 }; vectorCross3D(xcj, Ft_j, torque_j); } else { torque_j[0] = -sidata.crj * tor1; torque_j[1] = -sidata.crj * tor2; torque_j[2] = -sidata.crj * tor3; } i_forces.delta_torque[0] += torque_i[0]; i_forces.delta_torque[1] += torque_i[1]; i_forces.delta_torque[2] += torque_i[2]; j_forces.delta_torque[0] += torque_j[0]; j_forces.delta_torque[1] += torque_j[1]; j_forces.delta_torque[2] += torque_j[2]; #else i_forces.delta_torque[0] += -sidata.cri * tor1; i_forces.delta_torque[1] += -sidata.cri * tor2; i_forces.delta_torque[2] += -sidata.cri * tor3; j_forces.delta_torque[0] += -sidata.crj * tor1; j_forces.delta_torque[1] += -sidata.crj * tor2; j_forces.delta_torque[2] += -sidata.crj * tor3; #endif } } void surfacesClose(SurfacesCloseData & scdata, ForceData&, ForceData&) { // unset non-touching neighbors // TODO even if shearupdate == false? if(scdata.contact_flags) *scdata.contact_flags &= ~CONTACT_TANGENTIAL_MODEL; double * const shear = &scdata.contact_history[history_offset]; shear[0] = 0.0; shear[1] = 0.0; shear[2] = 0.0; } void beginPass(SurfacesIntersectData&, ForceData&, ForceData&){} void endPass(SurfacesIntersectData&, ForceData&, ForceData&){} protected: bool heating; bool heating_track; class ContactModelBase *cmb; }; } } #endif // TANGENTIAL_MODEL_LUDING_H_ #endif