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/*************************************************************************
* Copyright (C) 2010 by Jerome Duriez *
* jerome.duriez@hmg.inpg.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 <lib/high-precision/Constants.hpp>
#include <pkg/dem/KinemSimpleShearBox.hpp>
#include <core/State.hpp>
#include <pkg/common/Box.hpp>
#include <pkg/dem/FrictPhys.hpp>
namespace yade { // Cannot have #include directive inside.
YADE_PLUGIN((KinemSimpleShearBox))
void KinemSimpleShearBox::computeAlpha()
{
Quaternionr orientationLeftBox, orientationRightBox;
orientationLeftBox = leftbox->state->ori;
orientationRightBox = rightbox->state->ori;
if (orientationLeftBox.matrix() != orientationRightBox.matrix()) {
cout << "WARNING !!! your lateral boxes have not the same orientation, you're not in the case of a box imagined for creating these engines"
<< endl;
}
Real angle;
AngleAxisr aa(orientationLeftBox);
angle = aa.angle();
// orientationLeftBox.ToAxisAngle(axis,angle);
alpha = Mathr::PI / 2.0
- angle; // right if the initial orientation of the body (on the beginning of the simulation) is q =(1,0,0,0) = FromAxisAngle((0,0,1),0)
}
void KinemSimpleShearBox::computeScontact()
{
Real Xleft = leftbox->state->pos.x() + (YADE_CAST<Box*>(leftbox->shape.get()))->extents.x();
Real Xright = rightbox->state->pos.x() - (YADE_CAST<Box*>(rightbox->shape.get()))->extents.x();
Real Zfront = frontbox->state->pos.z() - YADE_CAST<Box*>(frontbox->shape.get())->extents.z();
Real Zback = backbox->state->pos.z() + (YADE_CAST<Box*>(backbox->shape.get()))->extents.z();
Scontact = (Xright - Xleft) * (Zfront - Zback); // that's so the value of section at the middle of the height of the box
}
void KinemSimpleShearBox::letMove(Real dX, Real dY)
{
if (LOG) cout << "It : " << scene->iter << endl;
// const Real& dt = scene->dt; // dt value obtained by getBoxes_Dt
Real Ysup = topbox->state->pos.y();
Real Ylat = leftbox->state->pos.y();
// Changes in vertical and horizontal velocities :
topbox->state->vel = Vector3r(dX / dt, dY / dt, 0);
leftbox->state->vel = Vector3r(dX / (2.0 * dt), dY / (2.0 * dt), 0);
rightbox->state->vel = Vector3r(dX / (2.0 * dt), dY / (2.0 * dt), 0);
if (LOG) cout << "dY that will be applied by NewtonIntegrator :" << dY << endl;
Real Ysup_mod = Ysup + dY;
Real Ylat_mod = Ylat + dY;
computeAlpha();
// Then computation of the angle of the rotation,dalpha, to be done :
if (alpha == Mathr::PI / 2.0) // Case of the very beginning
{
dalpha = -atan(dX / (Ysup_mod - Ylat_mod));
} else {
Real A = (Ysup_mod - Ylat_mod) * 2.0 * tan(alpha) / (2.0 * (Ysup - Ylat) + dX * tan(alpha));
dalpha = atan((A - tan(alpha)) / (1.0 + A * tan(alpha)));
}
Quaternionr qcorr(AngleAxisr(dalpha, Vector3r::UnitZ()));
// Rotation is applied through velocities (and NewtonIntegrator)
leftbox->state->angVel = Vector3r(0, 0, 1) * dalpha / dt;
rightbox->state->angVel = Vector3r(0, 0, 1) * dalpha / dt;
}
void KinemSimpleShearBox::stopMovement()
{
// upper plate's speed is zeroed
topbox->state->vel = Vector3r(0, 0, 0);
// same for left box
leftbox->state->vel = Vector3r(0, 0, 0);
leftbox->state->angVel = Vector3r(0, 0, 0);
// and for rightbox
rightbox->state->vel = Vector3r(0, 0, 0);
rightbox->state->angVel = Vector3r(0, 0, 0);
}
void KinemSimpleShearBox::computeStiffness()
{
int nbre_contacts = 0;
stiffness = 0.0;
InteractionContainer::iterator ii = scene->interactions->begin();
InteractionContainer::iterator iiEnd = scene->interactions->end();
for (; ii != iiEnd; ++ii) {
if ((*ii)->isReal()) {
const shared_ptr<Interaction>& contact = *ii;
Real fn = (static_cast<FrictPhys*>(contact->phys.get()))->normalForce.norm();
if (fn != 0) {
int id1 = contact->getId1(), id2 = contact->getId2();
if (id_topbox == id1 || id_topbox == id2) {
FrictPhys* currentContactPhysics = static_cast<FrictPhys*>(contact->phys.get());
stiffness += currentContactPhysics->kn;
nbre_contacts += 1;
}
}
}
}
if (LOG) cout << "nbre billes en contacts : " << nbre_contacts << endl;
if (LOG) cout << "rigidite echantillon calculee : " << stiffness << endl;
}
void KinemSimpleShearBox::getBoxes_Dt()
{
leftbox = Body::byId(id_boxleft);
rightbox = Body::byId(id_boxright);
frontbox = Body::byId(id_boxfront);
backbox = Body::byId(id_boxback);
topbox = Body::byId(id_topbox);
boxbas = Body::byId(id_boxbas);
dt = scene->dt;
}
void KinemSimpleShearBox::computeDY(Real KnC)
{
scene->forces.sync();
Vector3r fSup = scene->forces.getForce(id_topbox);
if (firstRun) {
alpha = Mathr::PI / 2.0;
;
y0 = topbox->state->pos.y();
f0 = fSup.y();
firstRun = false;
}
computeStiffness();
Real hCurrent = topbox->state->pos.y();
computeScontact();
Real fDesired = f0 + KnC * 1.0e9 * Scontact * (hCurrent - y0); // The value of the force desired, with the fact that KnC is in MPa/mm
if (stiffness == 0) {
deltaH = 0;
cerr << "Stiffness(sample) = 0 => DNC in fact : not CNL or CNS..." << endl;
} else {
deltaH = (fSup.y() - fDesired) / (stiffness);
}
if (LOG) cout << "Alors q je veux KnC = " << KnC << " depuis f0 = " << f0 << " et y0 = " << y0 << endl;
if (LOG) cout << "deltaH a permettre normalement :" << deltaH << endl;
deltaH = (1 - wallDamping) * deltaH;
if (LOG) cout << "deltaH apres amortissement :" << deltaH << endl;
if (math::abs(deltaH) > max_vel * scene->dt) {
deltaH = deltaH / math::abs(deltaH) * max_vel * scene->dt;
if (LOG) cout << "Correction appliquee pour ne pas depasser vmax(comp)" << endl;
}
}
} // namespace yade
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