void Ip2_FrictViscoMat_FrictViscoMat_FrictViscoPhys::go(const shared_ptr<Material>& b1, const shared_ptr<Material>& b2, const shared_ptr<Interaction>& interaction){
LOG_TRACE( "Ip2_FrictViscoMat_FrictViscoMat_FrictViscoPhys::go - contact law" );
if(interaction->phys) return;
const shared_ptr<FrictViscoMat>& mat1 = YADE_PTR_CAST<FrictViscoMat>(b1);
const shared_ptr<FrictViscoMat>& mat2 = YADE_PTR_CAST<FrictViscoMat>(b2);
interaction->phys = shared_ptr<FrictViscoPhys>(new FrictViscoPhys());
const shared_ptr<FrictViscoPhys>& contactPhysics = YADE_PTR_CAST<FrictViscoPhys>(interaction->phys);
Real Ea = mat1->young;
Real Eb = mat2->young;
Real Va = mat1->poisson;
Real Vb = mat2->poisson;
Real Ra,Rb;
assert(dynamic_cast<GenericSpheresContact*>(interaction->geom.get()));//only in debug mode
GenericSpheresContact* sphCont=YADE_CAST<GenericSpheresContact*>(interaction->geom.get());
Ra=sphCont->refR1>0?sphCont->refR1:sphCont->refR2;
Rb=sphCont->refR2>0?sphCont->refR2:sphCont->refR1;
// calculate stiffness from MatchMaker or use harmonic avarage as usual if not given
Real Kn = (kn) ? (*kn)(mat1->id,mat2->id) : 2.*Ea*Ra*Eb*Rb/(Ea*Ra+Eb*Rb);
Real Ks = (kRatio) ? (*kRatio)(mat1->id,mat2->id)*Kn : 2.*Ea*Ra*Va*Eb*Rb*Vb/(Ea*Ra*Va+Eb*Rb*Vb);
Real frictionAngle = (!frictAngle) ? std::min(mat1->frictionAngle,mat2->frictionAngle) : (*frictAngle)(mat1->id,mat2->id,mat1->frictionAngle,mat2->frictionAngle);
contactPhysics->tangensOfFrictionAngle = std::tan(frictionAngle);
contactPhysics->kn = Kn;
contactPhysics->ks = Ks;
/************************/
/* DAMPING COEFFICIENTS */
/************************/
Real betana = mat1->betan;
Real betanb = mat2->betan;
// inclusion of local viscous damping
if (betana!=0 || betanb!=0){
Body::id_t ida = interaction->getId1(); // get id body 1
Body::id_t idb = interaction->getId2(); // get id body 2
State* dea = Body::byId(ida,scene)->state.get();
State* deb = Body::byId(idb,scene)->state.get();
const shared_ptr<Body>& ba=Body::byId(ida,scene);
const shared_ptr<Body>& bb=Body::byId(idb,scene);
Real mbar = (!ba->isDynamic() && bb->isDynamic()) ? deb->mass : ((!bb->isDynamic() && ba->isDynamic()) ? dea->mass : (dea->mass*deb->mass / (dea->mass + deb->mass))); // get equivalent mass if both bodies are dynamic, if not set it equal to the one of the dynamic body
TRVAR2(Kn,mbar);
contactPhysics->cn_crit = 2.*sqrt(mbar*Kn); // Critical damping coefficient (normal direction)
contactPhysics->cn = contactPhysics->cn_crit * ( (betana!=0 && betanb!=0) ? ((betana+betanb)/2.) : ( (betanb==0) ? betana : betanb )); // Damping normal coefficient
}
else
contactPhysics->cn=0.;
TRVAR1(contactPhysics->cn);
}
void TriaxialStressController::controlExternalStress(int wall, Vector3r resultantForce, State* p, Real wall_max_vel) {
scene->forces.sync();
Real translation=normal[wall].dot(getForce(scene,wall_id[wall])-resultantForce);
const bool log=false;
if(log) LOG_DEBUG("wall="<<wall<<" actualForce="<<getForce(scene,wall_id[wall])<<", resultantForce="<<resultantForce<<", translation="<<translation);
if (translation!=0) {
if (stiffness[wall]!=0) {
translation /= stiffness[wall];
if(log) TRVAR2(translation,wall_max_vel*scene->dt)
translation = std::min( std::abs(translation), wall_max_vel*scene->dt ) * Mathr::Sign(translation);
}
else translation = wall_max_vel * Mathr::Sign(translation)*scene->dt;
}
previousTranslation[wall] = (1-stressDamping)*translation*normal[wall] + 0.8*previousTranslation[wall];// formula for "steady-flow" evolution with fluctuations
//Don't update position since Newton is doing that starting from bzr2612
//p->se3.position += previousTranslation[wall];
externalWork += previousTranslation[wall].dot(getForce(scene,wall_id[wall]));
//this is important is using VelocityBins. Otherwise the motion is never detected. Related to https://bugs.launchpad.net/yade/+bug/398089
p->vel=previousTranslation[wall]/scene->dt;
//if(log)TRVAR2(previousTranslation,p->se3.position);
}
