bool Law2_ScGeom_MindlinPhys_MindlinDeresiewitz::go(shared_ptr<IGeom>& ig, shared_ptr<IPhys>& ip, Interaction* contact){
Body::id_t id1(contact->getId1()), id2(contact->getId2());
ScGeom* geom = static_cast<ScGeom*>(ig.get());
MindlinPhys* phys=static_cast<MindlinPhys*>(ip.get());
const Real uN=geom->penetrationDepth;
if (uN<0) {
if (neverErase) {phys->shearForce = phys->normalForce = Vector3r::Zero(); phys->kn=phys->ks=0; return true;}
else {return false;}
}
// normal force
Real Fn=phys->kno*pow(uN,3/2.);
phys->normalForce=Fn*geom->normal;
// exactly zero would not work with the shear formulation, and would give zero shear force anyway
if(Fn==0) return true;
//phys->kn=3./2.*phys->kno*std::pow(uN,0.5); // update stiffness, not needed
// contact radius
Real R=geom->radius1*geom->radius2/(geom->radius1+geom->radius2);
phys->radius=pow(Fn*pow(R,3/2.)/phys->kno,1/3.);
// shear force: transform, but keep the old value for now
geom->rotate(phys->usTotal);
//Vector3r usOld=phys->usTotal; //The variable set but not used
Vector3r dUs=geom->shearIncrement();
phys->usTotal-=dUs;
#if 0
Vector3r shearIncrement;
shearIncrement=geom->shearIncrement();
Fs-=ks*shearIncrement;
// Mohr-Coulomb slip
Real maxFs2=pow(Fn,2)*pow(phys->tangensOfFrictionAngle,2);
if(Fs.squaredNorm()>maxFs2) Fs*=sqrt(maxFs2)/Fs.norm();
#endif
// apply forces
Vector3r f=-phys->normalForce-phys->shearForce;
scene->forces.addForce(id1,f);
scene->forces.addForce(id2,-f);
scene->forces.addTorque(id1,(geom->radius1-.5*geom->penetrationDepth)*geom->normal.cross(f));
scene->forces.addTorque(id2,(geom->radius2-.5*geom->penetrationDepth)*geom->normal.cross(f));
return true;
}
bool Law2_ScGeom_MindlinPhys_HertzWithLinearShear::go(shared_ptr<IGeom>& ig, shared_ptr<IPhys>& ip, Interaction* contact){
Body::id_t id1(contact->getId1()), id2(contact->getId2());
ScGeom* geom = static_cast<ScGeom*>(ig.get());
MindlinPhys* phys=static_cast<MindlinPhys*>(ip.get());
const Real uN=geom->penetrationDepth;
if (uN<0) {
if (neverErase) {phys->shearForce = phys->normalForce = Vector3r::Zero(); phys->kn=phys->ks=0; return true;}
else return false;
}
// normal force
Real Fn=phys->kno*pow(uN,3/2.);
phys->normalForce=Fn*geom->normal;
//phys->kn=3./2.*phys->kno*std::pow(uN,0.5); // update stiffness, not needed
// shear force
Vector3r& Fs=geom->rotate(phys->shearForce);
Real ks= nonLin>0 ? phys->kso*std::pow(uN,0.5) : phys->kso;
Vector3r shearIncrement;
if(nonLin>1){
State *de1=Body::byId(id1,scene)->state.get(), *de2=Body::byId(id2,scene)->state.get();
Vector3r shiftVel=scene->isPeriodic ? Vector3r(scene->cell->velGrad*scene->cell->hSize*contact->cellDist.cast<Real>()) : Vector3r::Zero();
Vector3r shift2 = scene->isPeriodic ? Vector3r(scene->cell->hSize*contact->cellDist.cast<Real>()): Vector3r::Zero();
Vector3r incidentV = geom->getIncidentVel(de1, de2, scene->dt, shift2, shiftVel, /*preventGranularRatcheting*/ nonLin>2 );
Vector3r incidentVn = geom->normal.dot(incidentV)*geom->normal; // contact normal velocity
Vector3r incidentVs = incidentV-incidentVn; // contact shear velocity
shearIncrement=incidentVs*scene->dt;
} else { shearIncrement=geom->shearIncrement(); }
Fs-=ks*shearIncrement;
// Mohr-Coulomb slip
Real maxFs2=pow(Fn,2)*pow(phys->tangensOfFrictionAngle,2);
if(Fs.squaredNorm()>maxFs2) Fs*=sqrt(maxFs2)/Fs.norm();
// apply forces
Vector3r f=-phys->normalForce-phys->shearForce; /* should be a reference returned by geom->rotate */ assert(phys->shearForce==Fs);
scene->forces.addForce(id1,f);
scene->forces.addForce(id2,-f);
scene->forces.addTorque(id1,(geom->radius1-.5*geom->penetrationDepth)*geom->normal.cross(f));
scene->forces.addTorque(id2,(geom->radius2-.5*geom->penetrationDepth)*geom->normal.cross(f));
return true;
}
void Law2_ScGeom_CFpmPhys_CohesiveFrictionalPM::go(shared_ptr<IGeom>& ig, shared_ptr<IPhys>& ip, Interaction* contact){
ScGeom* geom = static_cast<ScGeom*>(ig.get());
CFpmPhys* phys = static_cast<CFpmPhys*>(ip.get());
const int &id1 = contact->getId1();
const int &id2 = contact->getId2();
Body* b1 = Body::byId(id1,scene).get();
Body* b2 = Body::byId(id2,scene).get();
Real displN = geom->penetrationDepth; // NOTE: the sign for penetrationdepth is different from ScGeom and Dem3DofGeom: geom->penetrationDepth>0 when spheres interpenetrate
Real Dtensile=phys->FnMax/phys->kn;
Real Dsoftening = phys->strengthSoftening*Dtensile;
/*to set the equilibrium distance between all cohesive elements when they first meet -> allows one to work with initial stress-free assembly*/
if ( contact->isFresh(scene) ) { phys->initD = displN; phys->normalForce = Vector3r::Zero(); phys->shearForce = Vector3r::Zero();}
Real D = displN - phys->initD; // interparticular distance is computed depending on the equilibrium distance
/* Determination of interaction */
if (D < 0){ //spheres do not touch
if (!phys->isCohesive){ scene->interactions->requestErase(contact); return; } // destroy the interaction before calculation
if ((phys->isCohesive) && (abs(D) > (Dtensile + Dsoftening))) { // spheres are bonded and the interacting distance is greater than the one allowed ny the defined cohesion
phys->isCohesive=false;
// update body state with the number of broken bonds
CFpmState* st1=dynamic_cast<CFpmState*>(b1->state.get());
CFpmState* st2=dynamic_cast<CFpmState*>(b2->state.get());
st1->numBrokenCohesive+=1;
st2->numBrokenCohesive+=1;
//// the same thing but from ConcretePM
//const shared_ptr<Body>& body1=Body::byId(contact->getId1(),scene), body2=Body::byId(contact->getId2(),scene); assert(body1); assert(body2);
//const shared_ptr<CFpmState>& st1=YADE_PTR_CAST<CFpmState>(body1->state), st2=YADE_PTR_CAST<CFpmState>(body2->state);
//{ boost::mutex::scoped_lock lock(st1->updateMutex); st1->numBrokenCohesive+=1; }
//{ boost::mutex::scoped_lock lock(st2->updateMutex); st2->numBrokenCohesive+=1; }
// end of update
scene->interactions->requestErase(contact); return;
}
}
/*NormalForce*/
Real Fn=0, Dsoft=0;
if ((D < 0) && (abs(D) > Dtensile)) { //to take into account strength softening
Dsoft = D+Dtensile; // Dsoft<0 for a negative value of Fn (attractive force)
Fn = -(phys->FnMax+(phys->kn/phys->strengthSoftening)*Dsoft); // computes FnMax - FnSoftening
}
else {
Fn = phys->kn*D;
}
phys->normalForce = Fn*geom->normal; // NOTE normal is position2-position1 - It is directed from particle1 to particle2
/*ShearForce*/
Vector3r& shearForce = phys->shearForce;
// using scGeom function rotateAndGetShear
State* st1 = Body::byId(id1,scene)->state.get();
State* st2 = Body::byId(id2,scene)->state.get();
geom->rotate(phys->shearForce);
const Vector3r& dus = geom->shearIncrement();
//Linear elasticity giving "trial" shear force
shearForce -= phys->ks*dus;
// needed for the next timestep
phys->prevNormal = geom->normal;
/* Morh-Coulomb criterion */
Real maxFs = phys->FsMax + Fn*phys->tanFrictionAngle;
if (shearForce.squaredNorm() > maxFs*maxFs){
shearForce*=maxFs/shearForce.norm(); // to fix the shear force to its yielding value
}
/* Apply forces */
Vector3r f = phys->normalForce + shearForce;
// these lines to adapt to periodic boundary conditions (NOTE applyForceAtContactPoint computes torque induced by normal and shear force too)
if (!scene->isPeriodic)
applyForceAtContactPoint(f , geom->contactPoint , id2, st2->se3.position, id1, st1->se3.position);
else { // in scg we do not wrap particles positions, hence "applyForceAtContactPoint" cannot be used when scene is periodic
scene->forces.addForce(id1,-f);
scene->forces.addForce(id2,f);
scene->forces.addTorque(id1,(geom->radius1-0.5*geom->penetrationDepth)* geom->normal.cross(-f));
scene->forces.addTorque(id2,(geom->radius2-0.5*geom->penetrationDepth)* geom->normal.cross(-f));
}
/* Moment Rotation Law */
// NOTE this part could probably be computed in ScGeom to avoid copy/paste multiplication !!!
Quaternionr delta( b1->state->ori * phys->initialOrientation1.conjugate() *phys->initialOrientation2 * b2->state->ori.conjugate()); delta.normalize(); //relative orientation
AngleAxisr aa(delta); // axis of rotation - this is the Moment direction UNIT vector; angle represents the power of resistant ELASTIC moment
if(aa.angle() > Mathr::PI) aa.angle() -= Mathr::TWO_PI; // angle is between 0 and 2*pi, but should be between -pi and pi
phys->cumulativeRotation = aa.angle();
//Find angle*axis. That's all. But first find angle about contact normal. Result is scalar. Axis is contact normal.
Real angle_twist(aa.angle() * aa.axis().dot(geom->normal) ); //rotation about normal
Vector3r axis_twist(angle_twist * geom->normal);
Vector3r moment_twist(axis_twist * phys->kr);
Vector3r axis_bending(aa.angle()*aa.axis() - axis_twist); //total rotation minus rotation about normal
Vector3r moment_bending(axis_bending * phys->kr);
Vector3r moment = moment_twist + moment_bending;
Real MomentMax = phys->maxBend*std::fabs(phys->normalForce.norm());
Real scalarMoment = moment.norm();
/*Plastic moment */
if(scalarMoment > MomentMax)
{
Real ratio = 0;
ratio *= MomentMax/scalarMoment; // to fix the moment to its yielding value
moment *= ratio;
moment_twist *= ratio;
moment_bending *= ratio;
}
phys->moment_twist = moment_twist;
phys->moment_bending = moment_bending;
scene->forces.addTorque(id1,-moment);
scene->forces.addTorque(id2, moment);
}
bool Law2_ScGeom_JCFpmPhys_JointedCohesiveFrictionalPM::go(shared_ptr<IGeom>& ig, shared_ptr<IPhys>& ip, Interaction* contact){
const int &id1 = contact->getId1();
const int &id2 = contact->getId2();
ScGeom* geom = static_cast<ScGeom*>(ig.get());
JCFpmPhys* phys = static_cast<JCFpmPhys*>(ip.get());
Body* b1 = Body::byId(id1,scene).get();
Body* b2 = Body::byId(id2,scene).get();
Real Dtensile=phys->FnMax/phys->kn;
string fileCracks = "cracks_"+Key+".txt";
string fileMoments = "moments_"+Key+".txt";
/// Defines the interparticular distance used for computation
Real D = 0;
/*this is for setting the equilibrium distance between all cohesive elements at the first contact detection*/
if ( contact->isFresh(scene) ) {
phys->normalForce = Vector3r::Zero();
phys->shearForce = Vector3r::Zero();
if ((smoothJoint) && (phys->isOnJoint)) {
phys->jointNormal = geom->normal.dot(phys->jointNormal)*phys->jointNormal; //to set the joint normal colinear with the interaction normal
phys->jointNormal.normalize();
phys->initD = std::abs((b1->state->pos - b2->state->pos).dot(phys->jointNormal)); // to set the initial gap as the equilibrium gap
} else {
phys->initD = geom->penetrationDepth;
}
}
if ( smoothJoint && phys->isOnJoint ) {
if ( phys->more || ( phys-> jointCumulativeSliding > (2*min(geom->radius1,geom->radius2)) ) ) {
if (!neverErase) return false;
else {
phys->shearForce = Vector3r::Zero();
phys->normalForce = Vector3r::Zero();
phys->isCohesive =0;
phys->FnMax = 0;
phys->FsMax = 0;
return true;
}
} else {
D = phys->initD - std::abs((b1->state->pos - b2->state->pos).dot(phys->jointNormal));
}
} else {
D = geom->penetrationDepth - phys->initD;
}
phys->crackJointAperture = D<0? -D : 0.; // for DFNFlow
if (!phys->momentBroken && useStrainEnergy) phys->strainEnergy = 0.5*((pow(phys->normalForce.norm(),2)/phys->kn) + (pow(phys->shearForce.norm(),2)/phys->ks));
else if (!phys->momentBroken && !useStrainEnergy) computeKineticEnergy(phys, b1, b2);
//Compute clustered acoustic emission events:
if (recordMoments && !neverErase){
cerr << "Acoustic emissions algorithm requires neverErase=True, changing value from False to True" << endl;
neverErase=true;
}
if (phys->momentBroken && recordMoments && !phys->momentCalculated){
if (phys->originalClusterEvent && !phys->computedCentroid) computeCentroid(phys);
if (phys->originalClusterEvent) computeClusteredMoment(phys);
if (phys->momentCalculated && phys->momentMagnitude!=0){
std::ofstream file (fileMoments.c_str(), !momentsFileExist ? std::ios::trunc : std::ios::app);
if(file.tellp()==0){ file <<"i p0 p1 p2 moment numInts eventNum time beginTime"<<endl; }
file << boost::lexical_cast<string> ( scene->iter )<<" "<< boost::lexical_cast<string> ( phys->momentCentroid[0] ) <<" "<< boost::lexical_cast<string> ( phys->momentCentroid[1] ) <<" "<< boost::lexical_cast<string> ( phys->momentCentroid[2] ) <<" "<< boost::lexical_cast<string> ( phys->momentMagnitude ) << " " << boost::lexical_cast<string> ( phys->clusterInts.size() ) << " " << boost::lexical_cast<string> ( phys->eventNumber ) << " " << boost::lexical_cast<string> (scene->time) << " " << boost::lexical_cast<string> (phys->eventBeginTime) << endl;
momentsFileExist=true;
}
}
/* Determination of interaction */
if (D < 0) { //tensile configuration
if ( !phys->isCohesive) {
if (!neverErase) return false;
else {
phys->shearForce = Vector3r::Zero();
phys->normalForce = Vector3r::Zero();
phys->isCohesive =0;
phys->FnMax = 0;
phys->FsMax = 0;
return true;
}
}
if ( phys->isCohesive && (phys->FnMax>0) && (std::abs(D)>Dtensile) ) {
nbTensCracks++;
phys->isCohesive = 0;
phys->FnMax = 0;
phys->FsMax = 0;
/// Do we need both the following lines?
phys->breakOccurred = true; // flag to trigger remesh for DFNFlowEngine
phys->isBroken = true; // flag for DFNFlowEngine
// update body state with the number of broken bonds -> do we really need that?
JCFpmState* st1=dynamic_cast<JCFpmState*>(b1->state.get());
JCFpmState* st2=dynamic_cast<JCFpmState*>(b2->state.get());
st1->nbBrokenBonds++;
st2->nbBrokenBonds++;
st1->damageIndex+=1.0/st1->nbInitBonds;
st2->damageIndex+=1.0/st2->nbInitBonds;
phys->momentBroken = true;
Real scalarNF=phys->normalForce.norm();
Real scalarSF=phys->shearForce.norm();
totalTensCracksE+=0.5*( ((scalarNF*scalarNF)/phys->kn) + ((scalarSF*scalarSF)/phys->ks) );
totalCracksSurface += phys->crossSection;
if (recordCracks){
std::ofstream file (fileCracks.c_str(), !cracksFileExist ? std::ios::trunc : std::ios::app);
if(file.tellp()==0){ file <<"iter time p0 p1 p2 type size norm0 norm1 norm2 nrg onJnt"<<endl; }
Vector3r crackNormal=Vector3r::Zero();
if ((smoothJoint) && (phys->isOnJoint)) { crackNormal=phys->jointNormal; } else {crackNormal=geom->normal;}
file << boost::lexical_cast<string> ( scene->iter ) << " " << boost::lexical_cast<string> ( scene->time ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[0] ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[1] ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[2] ) <<" "<< 1 <<" "<< boost::lexical_cast<string> ( 0.5*(geom->radius1+geom->radius2) ) <<" "<< boost::lexical_cast<string> ( crackNormal[0] ) <<" "<< boost::lexical_cast<string> ( crackNormal[1] ) <<" "<< boost::lexical_cast<string> ( crackNormal[2] ) <<" "<< boost::lexical_cast<string> ( 0.5*( ((scalarNF*scalarNF)/phys->kn) + ((scalarSF*scalarSF)/phys->ks) ) ) <<" "<< boost::lexical_cast<string> ( phys->isOnJoint ) << endl;
}
if (recordMoments && !phys->momentCalculated){
checkForCluster(phys, geom, b1, b2, contact);
clusterInteractions(phys, contact);
computeTemporalWindow(phys, b1, b2);
}
cracksFileExist=true;
if (!neverErase) return false;
else {
phys->shearForce = Vector3r::Zero();
phys->normalForce = Vector3r::Zero();
return true;
}
}
}
/* NormalForce */
Real Fn = 0;
Fn = phys->kn*D;
/* ShearForce */
Vector3r& shearForce = phys->shearForce;
Real jointSliding=0;
if ((smoothJoint) && (phys->isOnJoint)) {
/// incremental formulation (OK?)
Vector3r relativeVelocity = (b2->state->vel - b1->state->vel); // angVel are not taken into account as particles on joint don't rotate ????
Vector3r slidingVelocity = relativeVelocity - phys->jointNormal.dot(relativeVelocity)*phys->jointNormal;
Vector3r incrementalSliding = slidingVelocity*scene->dt;
shearForce -= phys->ks*incrementalSliding;
jointSliding = incrementalSliding.norm();
phys->jointCumulativeSliding += jointSliding;
} else {
shearForce = geom->rotate(phys->shearForce);
const Vector3r& incrementalShear = geom->shearIncrement();
shearForce -= phys->ks*incrementalShear;
}
/* Mohr-Coulomb criterion */
Real maxFs = phys->FsMax + Fn*phys->tanFrictionAngle;
Real scalarShearForce = shearForce.norm();
if (scalarShearForce > maxFs) {
if (scalarShearForce != 0)
shearForce*=maxFs/scalarShearForce;
else
shearForce=Vector3r::Zero();
if ((smoothJoint) && (phys->isOnJoint)) {phys->dilation=phys->jointCumulativeSliding*phys->tanDilationAngle-D; phys->initD+=(jointSliding*phys->tanDilationAngle);}
// if (!phys->isCohesive) {
// nbSlips++;
// totalSlipE+=((1./phys->ks)*(trialForce-shearForce))/*plastic disp*/.dot(shearForce)/*active force*/;
//
// if ( (recordSlips) && (maxFs!=0) ) {
// std::ofstream file (fileCracks.c_str(), !cracksFileExist ? std::ios::trunc : std::ios::app);
// if(file.tellp()==0){ file <<"iter time p0 p1 p2 type size norm0 norm1 norm2 nrg"<<endl; }
// Vector3r crackNormal=Vector3r::Zero();
// if ((smoothJoint) && (phys->isOnJoint)) { crackNormal=phys->jointNormal; } else {crackNormal=geom->normal;}
// file << boost::lexical_cast<string> ( scene->iter ) <<" " << boost::lexical_cast<string> ( scene->time ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[0] ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[1] ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[2] ) <<" "<< 0 <<" "<< boost::lexical_cast<string> ( 0.5*(geom->radius1+geom->radius2) ) <<" "<< boost::lexical_cast<string> ( crackNormal[0] ) <<" "<< boost::lexical_cast<string> ( crackNormal[1] ) <<" "<< boost::lexical_cast<string> ( crackNormal[2] ) <<" "<< boost::lexical_cast<string> ( ((1./phys->ks)*(trialForce-shearForce)).dot(shearForce) ) << endl;
// }
// cracksFileExist=true;
// }
if ( phys->isCohesive ) {
nbShearCracks++;
phys->isCohesive = 0;
phys->FnMax = 0;
phys->FsMax = 0;
/// Do we need both the following lines?
phys->breakOccurred = true; // flag to trigger remesh for DFNFlowEngine
phys->isBroken = true; // flag for DFNFlowEngine
phys->momentBroken = true;
// update body state with the number of broken bonds -> do we really need that?
JCFpmState* st1=dynamic_cast<JCFpmState*>(b1->state.get());
JCFpmState* st2=dynamic_cast<JCFpmState*>(b2->state.get());
st1->nbBrokenBonds++;
st2->nbBrokenBonds++;
st1->damageIndex+=1.0/st1->nbInitBonds;
st2->damageIndex+=1.0/st2->nbInitBonds;
Real scalarNF=phys->normalForce.norm();
Real scalarSF=phys->shearForce.norm();
totalShearCracksE+=0.5*( ((scalarNF*scalarNF)/phys->kn) + ((scalarSF*scalarSF)/phys->ks) );
totalCracksSurface += phys->crossSection;
if (recordCracks){
std::ofstream file (fileCracks.c_str(), !cracksFileExist ? std::ios::trunc : std::ios::app);
if(file.tellp()==0){ file <<"iter time p0 p1 p2 type size norm0 norm1 norm2 nrg onJnt"<<endl; }
Vector3r crackNormal=Vector3r::Zero();
if ((smoothJoint) && (phys->isOnJoint)) { crackNormal=phys->jointNormal; } else {crackNormal=geom->normal;}
file << boost::lexical_cast<string> ( scene->iter ) << " " << boost::lexical_cast<string> ( scene->time ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[0] ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[1] ) <<" "<< boost::lexical_cast<string> ( geom->contactPoint[2] ) <<" "<< 2 <<" "<< boost::lexical_cast<string> ( 0.5*(geom->radius1+geom->radius2) ) <<" "<< boost::lexical_cast<string> ( crackNormal[0] ) <<" "<< boost::lexical_cast<string> ( crackNormal[1] ) <<" "<< boost::lexical_cast<string> ( crackNormal[2] ) <<" "<< boost::lexical_cast<string> ( 0.5*( ((scalarNF*scalarNF)/phys->kn) + ((scalarSF*scalarSF)/phys->ks) ) ) <<" "<< boost::lexical_cast<string> ( phys->isOnJoint ) << endl;
}
cracksFileExist=true;
// // option 1: delete contact whatsoever (if in compression, it will be detected as a new contact at the next timestep -> actually, not necesarily because of the near neighbour interaction: there could be a gap between the bonded particles and thus a broken contact may not be frictional at the next timestep if the detection is done for strictly contacting particles...) -> to TEST
// if (!neverErase) return false;
// else {
// phys->shearForce = Vector3r::Zero();
// phys->normalForce = Vector3r::Zero();
// return true;
// }
if (recordMoments && !phys->momentCalculated){
checkForCluster(phys, geom, b1, b2, contact);
clusterInteractions(phys, contact);
computeTemporalWindow(phys, b1, b2);
}
// option 2: delete contact if in tension
// shearForce *= Fn*phys->tanFrictionAngle/scalarShearForce; // now or at the next timestep? should not be very different -> to TEST
if ( D < 0 ) { // spheres do not touch
if (!neverErase) return false;
else {
phys->shearForce = Vector3r::Zero();
phys->normalForce = Vector3r::Zero();
return true;
}
}
}
}
/* Apply forces */
if ((smoothJoint) && (phys->isOnJoint)) { phys->normalForce = Fn*phys->jointNormal; } else { phys->normalForce = Fn*geom->normal; }
Vector3r f = phys->normalForce + shearForce;
/// applyForceAtContactPoint computes torque also and, for now, we don't want rotation for particles on joint (some errors in calculation due to specific geometry)
//applyForceAtContactPoint(f, geom->contactPoint, I->getId2(), b2->state->pos, I->getId1(), b1->state->pos, scene);
scene->forces.addForce (id1,-f);
scene->forces.addForce (id2, f);
// simple solution to avoid torque computation for particles interacting on a smooth joint
if ( (phys->isOnJoint)&&(smoothJoint) ) return true;
/// those lines are needed if rootBody->forces.addForce and rootBody->forces.addMoment are used instead of applyForceAtContactPoint -> NOTE need to check for accuracy!!!
scene->forces.addTorque(id1,(geom->radius1-0.5*geom->penetrationDepth)* geom->normal.cross(-f));
scene->forces.addTorque(id2,(geom->radius2-0.5*geom->penetrationDepth)* geom->normal.cross(-f));
return true;
}