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/*************************************************************************
* Copyright (C) 2006 by Bruno Chareyre *
* bruno.chareyre@grenoble-inp.fr *
* *
* This program is free software; it is licensed under the terms of the *
* GNU General Public License v2 or later. See file LICENSE for details. *
*************************************************************************/
#include "GlobalStiffnessTimeStepper.hpp"
#include <lib/high-precision/Constants.hpp>
#include <core/Clump.hpp>
#include <core/Interaction.hpp>
#include <core/Scene.hpp>
#include <pkg/common/Sphere.hpp>
#include <pkg/dem/DemXDofGeom.hpp>
#include <pkg/dem/FrictPhys.hpp>
#include <pkg/dem/ScGeom.hpp>
#include <pkg/dem/ViscoelasticPM.hpp>
#include <preprocessing/dem/Shop.hpp>
#ifdef YADE_MPI
#include <core/Subdomain.hpp>
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpragmas"
#pragma GCC diagnostic ignored "-Wsuggest-override"
#pragma GCC diagnostic ignored "-Wcast-function-type"
#include <mpi.h>
#pragma GCC diagnostic pop
#endif
namespace yade { // Cannot have #include directive inside.
using math::max;
using math::min; // using inside .cpp file is ok.
CREATE_LOGGER(GlobalStiffnessTimeStepper);
YADE_PLUGIN((GlobalStiffnessTimeStepper));
GlobalStiffnessTimeStepper::~GlobalStiffnessTimeStepper() { }
void GlobalStiffnessTimeStepper::findTimeStepFromBody(const shared_ptr<Body>& body, Scene* /*ncb*/)
{
State* sdec = body->state.get();
Vector3r& stiffness = stiffnesses[body->getId()];
Vector3r& Rstiffness = Rstiffnesses[body->getId()];
if (body->isClump()) { // if clump, we sum stifnesses of all members
const shared_ptr<Clump>& clump = YADE_PTR_CAST<Clump>(body->shape);
FOREACH(Clump::MemberMap::value_type & B, clump->members)
{
const shared_ptr<Body>& b = Body::byId(B.first, scene);
stiffness += stiffnesses[b->getId()];
Rstiffness += Rstiffnesses[b->getId()];
if (viscEl == true) {
viscosities[body->getId()] += viscosities[b->getId()];
Rviscosities[body->getId()] += Rviscosities[b->getId()];
}
}
}
Real dt;
if (!sdec || stiffness == Vector3r::Zero()) {
// No interaction on this body, return. If using density scaline fallback to PWaveTimestep-like equation for dt.
if (densityScaling) {
if (body->material and body->shape) {
shared_ptr<ElastMat> ebp = YADE_PTR_DYN_CAST<ElastMat>(body->material);
shared_ptr<Sphere> s = YADE_PTR_DYN_CAST<Sphere>(body->shape);
if (!ebp || !s) dt = defaultDt;
Real density = body->state->mass / ((4 / 3.) * Mathr::PI * pow(s->radius, 3));
dt = s->radius / sqrt(ebp->young / density);
// dt=defaultDt;
} else {
dt = defaultDt;
}
if (sdec->densityScaling <= 0) sdec->densityScaling = timestepSafetyCoefficient * pow(dt / targetDt, 2.0);
else
sdec->densityScaling = min(1.01 * sdec->densityScaling, timestepSafetyCoefficient * pow(dt / targetDt, 2.0));
}
return; // not possible to compute!
} else {
//Normal case: determine the elastic minimum eigenperiod (and if required determine also the viscous one separately and take the minimum of the two)
Real dtx, dty, dtz;
dt = max(max(stiffness.x(), stiffness.y()), stiffness.z());
if (dt != 0) {
dt = sdec->mass / dt;
computedSomething = true;
} //dt = squared eigenperiod of translational motion
else
dt = Mathr::MAX_REAL;
if (Rstiffness.x() != 0) {
dtx = sdec->inertia.x() / Rstiffness.x();
computedSomething = true;
} //dtx = squared eigenperiod of rotational motion around x
else
dtx = Mathr::MAX_REAL;
if (Rstiffness.y() != 0) {
dty = sdec->inertia.y() / Rstiffness.y();
computedSomething = true;
} else
dty = Mathr::MAX_REAL;
if (Rstiffness.z() != 0) {
dtz = sdec->inertia.z() / Rstiffness.z();
computedSomething = true;
} else
dtz = Mathr::MAX_REAL;
Real Rdt = math::min(math::min(dtx, dty), dtz); //Rdt = smallest squared eigenperiod for elastic rotational motions
dt = 1.41044 * timestepSafetyCoefficient * math::sqrt(math::min(dt, Rdt)); //1.41044 = sqrt(2)
}
//Viscous
if (viscEl == true) {
Vector3r& viscosity = viscosities[body->getId()];
Vector3r& Rviscosity = Rviscosities[body->getId()];
Real dtx_visc, dty_visc, dtz_visc;
Real dt_visc = max(max(viscosity.x(), viscosity.y()), viscosity.z());
if (dt_visc != 0) {
dt_visc = sdec->mass / dt_visc;
computedSomething = true;
} //dt = eigenperiod of the viscous translational motion
else {
dt_visc = Mathr::MAX_REAL;
}
if (Rviscosity.x() != 0) {
dtx_visc = sdec->inertia.x() / Rviscosity.x();
computedSomething = true;
} //dtx = eigenperiod of viscous rotational motion around x
else
dtx_visc = Mathr::MAX_REAL;
if (Rviscosity.y() != 0) {
dty_visc = sdec->inertia.y() / Rviscosity.y();
computedSomething = true;
} else
dty_visc = Mathr::MAX_REAL;
if (Rviscosity.z() != 0) {
dtz_visc = sdec->inertia.z() / Rviscosity.z();
computedSomething = true;
} else
dtz_visc = Mathr::MAX_REAL;
Real Rdt_visc = math::min(math::min(dtx_visc, dty_visc), dtz_visc); //Rdt = smallest squared eigenperiod for viscous rotational motions
dt_visc = 2 * timestepSafetyCoefficient * math::min(dt_visc, Rdt_visc);
//Take the minimum between the elastic and viscous minimum eigenperiod.
dt = math::min(dt, dt_visc);
}
//if there is a target dt, then we apply density scaling on the body, the inertia used in Newton will be mass/scaling, the weight is unmodified
if (densityScaling) {
if (sdec->densityScaling > 0) sdec->densityScaling = min(sdec->densityScaling * 1.05, pow(dt / targetDt, 2.0));
else
sdec->densityScaling = pow(dt / targetDt, 2.0);
newDt = targetDt;
}
//else we update dt normaly
else {
newDt = math::min(dt, newDt);
}
}
bool GlobalStiffnessTimeStepper::isActivated()
{
return (active && ((!computedOnce) || (scene->iter % timeStepUpdateInterval == 0) || (scene->iter < (long int)2)));
}
void GlobalStiffnessTimeStepper::computeTimeStep(Scene* ncb)
{
// for some reason, this line is necessary to have correct functioning (no idea _why_)
// see scripts/test/compare-identical.py, run with or without active=active.
active = active;
if (defaultDt < 0) defaultDt = timestepSafetyCoefficient * Shop::PWaveTimeStep(Omega::instance().getScene());
computeStiffnesses(ncb);
shared_ptr<BodyContainer>& bodies = ncb->bodies;
newDt = Mathr::MAX_REAL;
computedSomething = false;
for (const auto& b : *bodies) {
if (!b) { continue; }
if (b->isDynamic() && !b->isClumpMember()) findTimeStepFromBody(b, ncb);
}
if (densityScaling) (newDt = targetDt);
if (computedSomething || densityScaling) {
previousDt = min(
min(newDt, maxDt),
1.05 * previousDt); // at maximum, dt will be multiplied by 1.05 in one iterration, this is to prevent brutal switches from 0.000... to 1 in some computations
scene->dt = previousDt;
computedOnce = true;
} else if (!computedOnce)
scene->dt = defaultDt;
#ifdef YADE_MPI
if (parallelMode) {
if (scene->iter % timeStepUpdateInterval == 0) {
Real recvDt;
Real myDt = scene->dt;
MPI_Allreduce(&myDt, &recvDt, 1, MPI_DOUBLE, MPI_MIN, scene->getComm());
scene->dt = recvDt;
}
}
#endif
// LOG_INFO("computed timestep " << newDt <<
// (scene->dt==newDt ? string(", applied") :
// string(", BUT timestep is ")+boost::lexical_cast<string>(scene->dt))<<".");
}
void GlobalStiffnessTimeStepper::computeStiffnesses(Scene* rb)
{
/* check size */
size_t size = stiffnesses.size();
if (size < rb->bodies->size()) {
size = rb->bodies->size();
stiffnesses.resize(size);
Rstiffnesses.resize(size);
if (viscEl == true) {
viscosities.resize(size);
Rviscosities.resize(size);
}
}
#if (YADE_REAL_BIT <= 64)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpragmas"
// this is to remove warning about manipulating raw memory
#pragma GCC diagnostic ignored "-Wclass-memaccess"
/* reset stored values */
memset(&stiffnesses[0], 0, sizeof(Vector3r) * size);
memset(&Rstiffnesses[0], 0, sizeof(Vector3r) * size);
if (viscEl == true) {
memset(&viscosities[0], 0, sizeof(Vector3r) * size);
memset(&Rviscosities[0], 0, sizeof(Vector3r) * size);
}
#pragma GCC diagnostic pop
#else
// the standard way, perfectly optimized by compiler.
std::fill(stiffnesses.begin(), stiffnesses.end(), Vector3r::Zero());
std::fill(Rstiffnesses.begin(), Rstiffnesses.end(), Vector3r::Zero());
if (viscEl == true) {
std::fill(viscosities.begin(), viscosities.end(), Vector3r::Zero());
std::fill(Rviscosities.begin(), Rviscosities.end(), Vector3r::Zero());
}
#endif
FOREACH(const shared_ptr<Interaction>& contact, *rb->interactions)
{
if (!contact->isReal()) continue;
GenericSpheresContact* geom = YADE_CAST<GenericSpheresContact*>(contact->geom.get());
assert(geom);
NormShearPhys* phys = YADE_CAST<NormShearPhys*>(contact->phys.get());
assert(phys);
// all we need for getting stiffness
Vector3r& normal = geom->normal;
Real& kn = phys->kn;
Real& ks = phys->ks;
Real& radius1 = geom->refR1;
Real& radius2 = geom->refR2;
Real fn = (static_cast<NormShearPhys*>(contact->phys.get()))->normalForce.squaredNorm();
if (fn == 0) continue; //Is it a problem with some laws? I still don't see why.
//Diagonal terms of the translational stiffness matrix
Vector3r diag_stiffness = Vector3r(math::pow(normal.x(), 2), math::pow(normal.y(), 2), math::pow(normal.z(), 2));
diag_stiffness *= kn - ks;
diag_stiffness = diag_stiffness + Vector3r(1, 1, 1) * ks;
//diagonal terms of the rotational stiffness matrix
// Vector3r branch1 = currentContactGeometry->normal*currentContactGeometry->radius1;
// Vector3r branch2 = currentContactGeometry->normal*currentContactGeometry->radius2;
Vector3r diag_Rstiffness = Vector3r(
math::pow(normal.y(), 2) + math::pow(normal.z(), 2),
math::pow(normal.x(), 2) + math::pow(normal.z(), 2),
math::pow(normal.x(), 2) + math::pow(normal.y(), 2));
diag_Rstiffness *= ks;
Vector3r diag_Mstiffness = Vector3r::Zero();
// If contact moments are present, add the diagonal of (n⊗n*k_twist + (I-n⊗n)*k_roll = (k_twist-k_roll)*n⊗n + I*k_roll ) :
const auto RotStiffFrictPhys_ptr = dynamic_cast<RotStiffFrictPhys*>(contact->phys.get());
if (RotStiffFrictPhys_ptr) {
// Rotational stiffness is supported
Vector3r kr = RotStiffFrictPhys_ptr->getRotStiffness(); //get the vector (k_twist,k_roll,k_roll)
Vector3r nn(math::pow(normal.x(), 2), math::pow(normal.y(), 2), math::pow(normal.z(), 2)); //n⊗n
diag_Mstiffness = (kr[0] - kr[1]) * nn + Vector3r(1, 1, 1) * kr[1];
}
stiffnesses[contact->getId1()] += diag_stiffness;
Rstiffnesses[contact->getId1()] += diag_Rstiffness * pow(radius1, 2) + diag_Mstiffness;
stiffnesses[contact->getId2()] += diag_stiffness;
Rstiffnesses[contact->getId2()] += diag_Rstiffness * pow(radius2, 2) + diag_Mstiffness;
//Same for the Viscous part, if required
if (viscEl == true) {
ViscElPhys* viscPhys = YADE_CAST<ViscElPhys*>(contact->phys.get());
assert(viscPhys);
Real& cn = viscPhys->cn;
Real& cs = viscPhys->cs;
//Diagonal terms of the translational viscous matrix
Vector3r diag_viscosity = Vector3r(math::pow(normal.x(), 2), math::pow(normal.y(), 2), math::pow(normal.z(), 2));
diag_viscosity *= cn - cs;
diag_viscosity = diag_viscosity + Vector3r(1, 1, 1) * cs;
//diagonal terms of the rotational viscous matrix
Vector3r diag_Rviscosity = Vector3r(
math::pow(normal.y(), 2) + math::pow(normal.z(), 2),
math::pow(normal.x(), 2) + math::pow(normal.z(), 2),
math::pow(normal.x(), 2) + math::pow(normal.y(), 2));
diag_Rviscosity *= cs;
// Add the contact stiffness matrix to the two particles one
viscosities[contact->getId1()] += diag_viscosity;
Rviscosities[contact->getId1()] += diag_Rviscosity * pow(radius1, 2);
viscosities[contact->getId2()] += diag_viscosity;
Rviscosities[contact->getId2()] += diag_Rviscosity * pow(radius2, 2);
}
}
}
} // namespace yade
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