// This method handles the pressure equation of state. Its tasks are
// 1. Calculate the new pressure
// 2. Update particle pressure
// 3. Increment the particle energy
// 4. Call plasticLaw to see if it wants to change the shear modulus
// 5. Optionally change delV (which is passed by reference)
// Notes:
// delV is incremental volume change on this step.
// J is total volume change at end of step (but it is 1 for low-strain materials)
void IsoPlasticity::UpdatePressure(MPMBase *mptr,double &delV,double J,int np,PlasticProperties *p,ResidualStrains *res,double eres) const
{ // pressure change
double dP = -p->Kred*delV;
mptr->IncrementPressure(dP);
// work energy is dU = -P dV + s.de(total)
// Here do hydrostatic term
// Work energy increment per unit mass (dU/(rho0 V0)) (uJ/g)
double avgP = mptr->GetPressure()-0.5*dP;
mptr->AddWorkEnergyAndResidualEnergy(-avgP*delV,-3.*avgP*eres);
// heat energy is Cv dT - dPhi
// Here do Cv dT term and dPhi is done later
IncrementHeatEnergy(mptr,res->dT,0.,0.);
}
// To allow some subclasses to support large deformations, the initial calculation for incremental
// deformation gradient (the dvij), volume change (delV) and relative volume (Jnew) can be
// handled first by the subclass. This mtehod then finishes the constitutive law
void IsoPlasticity::PlasticityConstLaw(MPMBase *mptr,double dvxx,double dvyy,double dvzz,double dvxy,double dvyx,
double dvxz,double dvzx,double dvyz,double dvzy,double delTime,int np,double delV,double Jnew,double eres,
PlasticProperties *p,ResidualStrains *res) const
{
// here dvij is total strain increment, dexxr is relative strain by subtracting off eres
double dexxr=dvxx-eres;
double deyyr=dvyy-eres;
double dezzr=dvzz-eres; // use in plane strain only
double dgxy=dvxy+dvyx;
double dgxz=dvxz+dvzx;
double dgyz=dvyz+dvzy;
// rotational strain increments (particle updated by Hypo3D)
double dwrotxy=dvyx-dvxy;
double dwrotxz=dvzx-dvxz;
double dwrotyz=dvzy-dvyz;
// allow arbitrary equation of state for pressure
UpdatePressure(mptr,delV,Jnew,np,p,res,eres);
// Elastic deviatoric stress increment
Tensor *ep=mptr->GetStrainTensor();
Tensor *sp=mptr->GetStressTensor();
Tensor stk,st0=*sp;
double dsig[6];
double thirdDelV = delV/3.;
dsig[XX] = 2.*p->Gred*(dexxr-thirdDelV);
dsig[YY] = 2.*p->Gred*(deyyr-thirdDelV);
dsig[ZZ] = 2.*p->Gred*(dezzr-thirdDelV);
dsig[YZ] = p->Gred*dgyz;
dsig[XZ] = p->Gred*dgxz;
dsig[XY] = p->Gred*dgxy;
stk.xx = st0.xx + dsig[XX];
stk.yy = st0.yy + dsig[YY];
stk.zz = st0.zz + dsig[ZZ];
stk.yz = st0.yz + dsig[YZ];
stk.xz = st0.xz + dsig[XZ];
stk.xy = st0.xy + dsig[XY];
// Calculate plastic potential f = ||s|| - sqrt(2/3)*sy(alpha,rate,...)
HardeningAlpha alpha;
plasticLaw->UpdateTrialAlpha(mptr,np,&alpha); // initialize to last value
double strial = GetMagnitudeSFromDev(&stk,np);
double ftrial = strial - SQRT_TWOTHIRDS*plasticLaw->GetYield(mptr,np,delTime,&alpha,p->hardProps);
if(ftrial<0.)
{ // elastic, update stress and strain energy as usual
// Add to total strain
ep->xx+=dvxx;
ep->yy+=dvyy;
ep->zz+=dvzz;
ep->xy+=dgxy;
ep->xz+=dgxz;
ep->yz+=dgyz;
// update stress (need to make hypoelastic)
Hypo3DCalculations(mptr,dwrotxy,dwrotxz,dwrotyz,dsig);
// work energy increment per unit mass (dU/(rho0 V0)) (uJ/g)
mptr->AddWorkEnergy(0.5*((st0.xx+sp->xx)*dvxx
+ (st0.yy+sp->yy)*dvyy
+ (st0.zz+sp->zz)*dvzz
+ (st0.yz+sp->yz)*dgyz
+ (st0.xz+sp->xz)*dgxz
+ (st0.xy+sp->xy)*dgxy));
// heat energy is Cv(dT-dTq0) - dPhi, but dPhi is zero here
// and Cv(dT-dTq0) was done in Update Pressure
// give material chance to update history variables that change in elastic updates
ElasticUpdateFinished(mptr,np,delTime);
return;
}
// Find direction of plastic strain and lambda for this plastic state
// Base class finds it numerically, subclass can override if solvable by more efficient meethods
Tensor dfds;
GetDfDsigma(strial,&stk,np,&dfds);
double lambdak = plasticLaw->SolveForLambdaBracketed(mptr,np,strial,&stk,p->Gred,1.,1.,delTime,&alpha,p->hardProps);
// Now have lambda, finish update on this particle
// Plastic strain increments on particle
double dexxp = lambdak*dfds.xx;
double deyyp = lambdak*dfds.yy;
double dezzp = lambdak*dfds.zz;
double dgxyp = 2.*lambdak*dfds.xy; // 2 for engineering plastic shear strain
double dgxzp = 2.*lambdak*dfds.xz; // 2 for engineering plastic shear strain
double dgyzp = 2.*lambdak*dfds.yz; // 2 for engineering plastic shear strain
Tensor *eplast=mptr->GetPlasticStrainTensor();
eplast->xx += dexxp;
eplast->yy += deyyp;
eplast->zz += dezzp;
eplast->xy += dgxyp;
eplast->xz += dgxzp;
eplast->yz += dgyzp;
// Elastic strain increments on particle
ep->xx += (dvxx-dexxp);
ep->yy += (dvyy-deyyp);
ep->zz += (dvzz-dezzp);
dgxy -= dgxyp;
ep->xy += dgxy;
dgxz -= dgxzp;
ep->xz += dgxz;
dgyz -= dgyzp;
ep->yz += dgyz;
// Elastic strain increment minus the residual terms by now subtracting plastic parts
dexxr -= dexxp;
deyyr -= deyyp;
dezzr -= dezzp; // plain strain only
//dgxy, dgxz, dgyz done above
// increment particle deviatoric stresses
dsig[XX] -= 2.*p->Gred*dexxp;
dsig[YY] -= 2.*p->Gred*deyyp;
dsig[ZZ] -= 2.*p->Gred*dezzp;
dsig[YZ] -= p->Gred*dgyzp;
dsig[XZ] -= p->Gred*dgxzp;
dsig[XY] -= p->Gred*dgxyp;
Hypo3DCalculations(mptr,dwrotxy,dwrotxz,dwrotyz,dsig);
// work energy increment per unit mass (dU/(rho0 V0)) (uJ/g)
double workEnergy = 0.5*((st0.xx+sp->xx)*dvxx + (st0.yy+sp->yy)*dvzz
+ (st0.zz+sp->zz)*dvzz + (st0.yz+sp->yz)*dgyz
+ (st0.xz+sp->xz)*dgxz + (st0.xy+sp->xy)*dgxy);
// plastic strain work
double plastEnergy = lambdak*(sp->xx*dfds.xx + sp->yy*dfds.yy + sp->zz*dfds.zz
+ 2.*sp->xy*dfds.xy + 2.*sp->xz*dfds.xz + 2.*sp->yz*dfds.yz);
// total work
mptr->AddWorkEnergy(plastEnergy + workEnergy);
// disispated energy per unit mass (dPhi/(rho0 V0)) (uJ/g)
double qdalphaTerm = lambdak*SQRT_TWOTHIRDS*plasticLaw->GetYieldIncrement(mptr,np,delTime,&alpha,p->hardProps);
double dispEnergy = plastEnergy - qdalphaTerm;
// heat energy is Cv(dT-dTq0) - dPhi
// The dPhi is subtracted here because it will show up in next
// time step within Cv dT (if adiabatic heating occurs)
// The Cv(dT-dTq0) was done already in update pressure
IncrementHeatEnergy(mptr,0.,0.,dispEnergy);
// The cumulative dissipated energy is tracked in plastic energy
// Setting the disp energy allows heating if mechanical energy is on
mptr->AddPlastEnergy(dispEnergy);
// update internal variables
plasticLaw->UpdatePlasticInternal(mptr,np,&alpha);
}
// Apply Constitutive law, check np to know what type
void TaitLiquid::MPMConstitutiveLaw(MPMBase *mptr,Matrix3 du,double delTime,int np,void *properties,
ResidualStrains *res,int historyOffset) const
{
#ifdef NO_SHEAR_MODEL
// get incremental deformation gradient
const Matrix3 dF = du.Exponential(incrementalDefGradTerms);
// decompose dF into dR and dU
Matrix3 dR;
Matrix3 dU = dF.RightDecompose(&dR,NULL);
// current deformation gradient
double detdF = dF.determinant();
Matrix3 pF = mptr->GetDeformationGradientMatrix();
Matrix3 F = dR*pF;
if(np==THREED_MPM)
F.Scale(pow(detdF,1./3.));
else
F.Scale2D(sqrt(detdF));
// new deformation matrix with volume change onle
mptr->SetDeformationGradientMatrix(F);
#else
#ifdef ELASTIC_B_MODEL
// get incremental deformation gradient
const Matrix3 dF = du.Exponential(incrementalDefGradTerms);
double detdF = dF.determinant();
// current deformation gradient
Matrix3 pF = mptr->GetDeformationGradientMatrix();
// new deformation matrix
const Matrix3 F = dF*pF;
mptr->SetDeformationGradientMatrix(F);
#else
// Update total deformation gradient, and calculate trial B
double detdF = IncrementDeformation(mptr,du,NULL,np);
#endif
#endif
// Get new J and save result on the particle
double J = detdF * mptr->GetHistoryDble(J_History,historyOffset);
mptr->SetHistoryDble(J_History,J,historyOffset);
#ifdef ELASTIC_B_MODEL
// store pressure strain as elastic B
Tensor *pB = mptr->GetAltStrainTensor() ;
if(np==THREED_MPM || np==AXISYMMETRIC_MPM)
{ double J23 = pow(J,2./3.);
pB->xx = J23;
pB->yy = J23;
pB->zz = J23;
}
else
{ pB->xx = J;
pB->yy = J;
}
#endif
// account for residual stresses
double dJres = GetIncrementalResJ(mptr,res);
double Jres = dJres * mptr->GetHistoryDble(J_History+1,historyOffset);
mptr->SetHistoryDble(J_History+1,Jres,historyOffset);
double Jeff = J/Jres;
// new Kirchhoff pressure (over rho0) from Tait equation
double p0=mptr->GetPressure();
double pressure = J*TAIT_C*Ksp*(exp((1.-Jeff)/TAIT_C)-1.);
mptr->SetPressure(pressure);
// incremental energy per unit mass - dilational part
double avgP = 0.5*(p0+pressure);
double delV = 1. - 1./detdF;
double workEnergy = -avgP*delV;
// incremental residual energy per unit mass
double delVres = 1. - 1./dJres;
double resEnergy = -avgP*delVres;
// viscosity term = 2 eta (0.5(grad v) + 0.5*(grad V)^T - (1/3) tr(grad v) I) = 2 eta dev(grad v)
// (i.e., deviatoric part of the symmetric strain tensor, 2 is for conversion to engineering shear strain)
// simple shear rate = |2 dev(grad v)|
Matrix3 shear;
double c[3][3];
double shearRate;
c[0][0] = (2.*du(0,0)-du(1,1)-du(2,2))/3.;
c[1][1] = (2.*du(1,1)-du(0,0)-du(2,2))/3.;
c[2][2] = (2.*du(2,2)-du(0,0)-du(1,1))/3.;
c[0][1] = 0.5*(du(0,1)+du(1,0));
c[1][0] = c[0][1];
shearRate = c[0][0]*c[0][0] + c[1][1]*c[1][1] + c[2][2]*c[2][2]
+ 2.*c[0][1]*c[0][1];
if(np==THREED_MPM)
{ c[0][2] = 0.5*(du(0,2)+du(2,0));
c[2][0] = c[0][2];
c[1][2] = 0.5*(du(1,2)+du(2,1));
c[2][1] = c[1][2];
shearRate += 2.*(c[0][2]*c[0][2] + c[1][2]*c[1][2]);
shear.set(c);
}
else
shear.set(c[0][0],c[0][1],c[1][0],c[1][1],c[2][2]);
shearRate = 2.*sqrt(shearRate)/delTime;
// Store shear rate
mptr->SetHistoryDble(J_History+2,shearRate,historyOffset);
// Get effective visocisy
double twoetaspRate = 0.;
if(numViscosity==1)
{ twoetaspRate = TwoEtasp[0];
}
else
{ shearRate = log10(shearRate);
if(shearRate < logShearRate[0])
twoetaspRate = TwoEtasp[0];
else if(shearRate > logShearRate[numViscosity-1])
twoetaspRate = TwoEtasp[numViscosity-1];
else
{ // interpolate
for(int i=1;i<numViscosity;i++)
{ if(shearRate <= logShearRate[i])
{ // between i-1 and i
double fract = (logShearRate[i]-shearRate)/(logShearRate[i]-logShearRate[i-1]);
twoetaspRate = fract*TwoEtasp[i-1] + (1.-fract)*TwoEtasp[i];
break;
}
}
}
}
// Get Kirchoff shear stress (over rho0)
shear.Scale(J*twoetaspRate/delTime);
// update deviatoric stress
Tensor *sp=mptr->GetStressTensor();
sp->xx = shear(0,0);
sp->yy = shear(1,1);
sp->zz = shear(2,2);
sp->xy = shear(0,1);
if(np==THREED_MPM)
{ sp->xz = shear(0,2);
sp->yz = shear(1,2);
}
// shear work per unit mass = tau.du = tau.tau*delTime/twoetaspRate
double shearWork = sp->xx*sp->xx + sp->yy*sp->yy + sp->zz*sp->zz + 2.*sp->xy*sp->xy;
if(np==THREED_MPM) shearWork += 2.*(sp->xz*sp->xz + sp->yz*sp->yz);
shearWork *= delTime/twoetaspRate;
mptr->AddWorkEnergyAndResidualEnergy(workEnergy+shearWork,resEnergy);
// particle isentropic temperature increment dT/T = - J (K/K0) gamma0 Delta(V)/V
// Delta(V)/V = 1. - 1/detdF (total volume)
double Kratio = Jeff*(1.+pressure/(TAIT_C*Ksp));
double dTq0 = -J*Kratio*gamma0*mptr->pPreviousTemperature*delV;
// heat energy is Cv (dT - dTq0) -dPhi
// Here do Cv (dT - dTq0)
// dPhi = shearWork is lost due to shear term
IncrementHeatEnergy(mptr,res->dT,dTq0,shearWork);
}
// To allow some subclasses to support large deformations, the initial calculation for incremental
// deformation gradient (the dvij), volume change (delV) and relative volume (Jnew) can be
// handled first by the subclass. This mtehod then finishes the constitutive law
void IsoPlasticity::PlasticityConstLaw(MPMBase *mptr,double dvxx,double dvyy,double dvxy,double dvyx,
double dvzz,double delTime,int np,double delV,double Jnew,double eres,
PlasticProperties *p,ResidualStrains *res) const
{
// here dvij is total strain increment, dexxr is relative strain by subtracting off eres
double dexxr = dvxx-eres; // trial dexx=dvxx
double deyyr = dvyy-eres; // trial deyy=dvyy
double dezzr = dvzz-eres; // In plane strain trial dezz=0, dvzz=0 except in axisymmetric
double dgxy = dvxy+dvyx; // no need to substract residual strain
double dwrotxy = dvyx-dvxy;
// allow arbitrary equation of state for pressure
double P0 = mptr->GetPressure();
UpdatePressure(mptr,delV,Jnew,np,p,res,eres);
double Pfinal = mptr->GetPressure();
// Deviatoric stress increment
Tensor *ep=mptr->GetStrainTensor();
Tensor *sp=mptr->GetStressTensor();
Tensor dels,stk,st0=*sp;
double thirdDelV = delV/3.;
dels.xx = 2.*p->Gred*(dexxr-thirdDelV);
dels.yy = 2.*p->Gred*(deyyr-thirdDelV);
if(np==PLANE_STRESS_MPM)
dels.zz = Pfinal-P0;
else
dels.zz = 2.*p->Gred*(dezzr-thirdDelV);
dels.xy = p->Gred*dgxy;
// trial deviatoric stress
stk.xx = st0.xx + dels.xx;
stk.yy = st0.yy + dels.yy;
stk.zz = st0.zz + dels.zz;
stk.xy = st0.xy + dels.xy;
// Calculate plastic potential f = ||s|| - sqrt(2/3)*sy(alpha,rate,...)
HardeningAlpha alpha;
plasticLaw->UpdateTrialAlpha(mptr,np,&alpha); // initialize to last value and zero plastic strain rate
double strial = GetMagnitudeSFromDev(&stk,np);
double ftrial = strial - SQRT_TWOTHIRDS*plasticLaw->GetYield(mptr,np,delTime,&alpha,p->hardProps);
if(ftrial<0.)
{ // elastic, update stress and strain energy as usual
// Add input strain increment to elastic strain on particle
ep->xx += dvxx;
ep->yy += dvyy;
ep->xy += dgxy;
// increment deviatoric stress (Units N/m^2 cm^3/g) (pressure not needed here)
Hypo2DCalculations(mptr,-dwrotxy,dels.xx,dels.yy,dels.xy);
// work energy increment per unit mass (dU/(rho0 V0)) (by midpoint rule) (uJ/g)
// energy units are also Pa cm^3/g, i.e., same as stress units
sp->zz = stk.zz;
if(np==AXISYMMETRIC_MPM)
{ ep->zz += dvzz;
mptr->AddWorkEnergy(0.5*((st0.xx+sp->xx)*dvxx + (st0.yy+sp->yy)*dvyy
+ (st0.xy+sp->xy)*dgxy + (st0.zz+sp->zz)*dvzz));
}
else
{ mptr->AddWorkEnergy(0.5*((st0.xx+sp->xx)*dvxx + (st0.yy+sp->yy)*dvyy
+ (st0.xy+sp->xy)*dgxy));
}
// heat energy is Cv(dT-dTq0) - dPhi, but dPhi is zero here
// and Cv(dT-dTq0) was done in Update pressure
// give subclass material chance to update history variables that change in elastic updates
ElasticUpdateFinished(mptr,np,delTime);
return;
}
// Find lambda for this plastic state
// Base class finds it numerically, subclass can override if solvable by more efficient methods
double lambdak = plasticLaw->SolveForLambdaBracketed(mptr,np,strial,&stk,p->Gred,p->psKred,Pfinal,delTime,&alpha,p->hardProps);
// Now have lambda, finish update on this particle
Tensor dfds;
if(np==PLANE_STRESS_MPM)
{ // get final stress state
double d1 = (1 + p->psKred*lambdak);
double d2 = (1.+2.*p->Gred*lambdak);
double n1 = (stk.xx+stk.yy-2.*Pfinal)/d1;
double n2 = (-stk.xx+stk.yy)/d2;
double sxx = (n1-n2)/2.;
double syy = (n1+n2)/2.;
double txy = stk.xy/d2;
// find increment in deviatoric stress
dels.xx = sxx+Pfinal-st0.xx;
dels.yy = syy+Pfinal-st0.yy;
dels.xy = txy-st0.xy;
// get final direction
dfds.xx = (2.*sxx-syy)/3.;
dfds.yy = (2.*syy-sxx)/3.;
dfds.zz = -(dfds.xx+dfds.yy);
dfds.xy = txy; // tensorial shear strain
// If fully plastic, the increment in deviatoric stress should be zero
// sxx = sigmaxx+Pfinal = st0.xx, syy = sigmayy+Pfinal = st0.yy, szz = Pfinal
// But first two must be wrong because trace is no longer zero?
//
// This is probably wrong
// i.e.: n1 + 2*Pfinal = st0.xx+st0.yy
// (stk.xx+stk.yy)/d1 - 2*Pfinal*(1/d1-1) = st0.xx+st0.yy
// But (stk.xx+stk.yy) = (st0.xx+st0.yy) + 2.*Gred*(dexxr+deyyr-2*thirdDelV)
// (st0.xx+st0.yy)(1/d1-1) - 2*Pfinal*(1/d1-1) = -2.*Gred*(dexxr+deyyr-2*thirdDelV)/d1
// (st0.xx+st0.yy-2*Pfinal)*(1-d1) = -2.*Gred*(dexxr+deyyr-2*thirdDelV)
// B*Kred*lam = 2.*Gred*A or lam = 2.*Gred*A/(B*Kred)
// where B = st0.xx+st0.yy-2*Pfinal, and A = (dexxr+deyyr-2*thirdDelV)
// Then d1 = 1+2*Gred*A/B, n1 = ((st0.xx+st0.yy) + 2*Gred*A - 2*Pfinal)/d1 = (B+2*Gred*A)*B/(B+2*Gred*A) = B
//
// Also expect syy-sxx = sigmayy-sigmaxx = st0.yy-st0.xx = n2
// (stk.yy-stk.xx)/d2 = st0.yy-st0.xx
// (st0.yy-st0.xx)/d2 + 2*Gred*(deyyr-dexxr)/d2 = (st0.yy-st0.xx)
// (st0.yy-st0.xx)(d2-1) = - 2*Gred*(deyyr-dexxr)
// lam = (deyyr-dexxr)/(st0.yy-st0.xx)
// Then n2 = (st0.yy-st0.xx + 2*Gred*(deyyr-dexxr))/(1+2*Gred*(deyyr-dexxr)/(st0.yy-st0.xx)) = st0.yy-st0.xx
//
// But these to lam's seem to differ?
// We can write
}
else
{ // get final direction
GetDfDsigma(strial,&stk,np,&dfds);
}
// Plastic strain increments on particle
double dexxp = lambdak*dfds.xx;
double deyyp = lambdak*dfds.yy;
double dezzp = lambdak*dfds.zz;
double dgxyp = 2.*lambdak*dfds.xy; // 2 for engineering plastic shear strain
Tensor *eplast=mptr->GetPlasticStrainTensor();
eplast->xx += dexxp;
eplast->yy += deyyp;
eplast->xy += dgxyp;
eplast->zz += dezzp;
// Elastic strain increments on particle
ep->xx += (dvxx-dexxp);
ep->yy += (dvyy-deyyp);
dgxy -= dgxyp;
ep->xy += dgxy;
if(np==PLANE_STRESS_MPM)
ep->zz += eres - p->psLr2G*(dexxr+deyyr+dezzp);
else
{ // plain strain and axisymmetric when plastic increments is dezzp
// In plain strain, dvzz=0 elastic increment is -dezzp to zz strain total is zero
// Axisymmetry can have non-zero hoop strain
ep->zz += (dvzz-dezzp);
dezzr -= dezzp;
}
// Elastic strain increment minus the residual terms by now subtracting plastic parts
dexxr -= dexxp;
deyyr -= deyyp;
//dgxy -= dgxyp; // done above
//dezzr -= dezzp; // plane strain and axisymmetry done above, plain stress not needed
// increment particle deviatoric stresses (plane stress increments found above)
if(np!=PLANE_STRESS_MPM)
{ dels.xx -= 2.*p->Gred*dexxp;
dels.yy -= 2.*p->Gred*deyyp;
dels.xy -= p->Gred*dgxyp;
dels.zz -= 2.*p->Gred*dezzp;
sp->zz += dels.zz;
}
else
sp->zz = Pfinal; // now equal to Pfinal
Hypo2DCalculations(mptr,-dwrotxy,dels.xx,dels.yy,dels.xy);
// Elastic work increment per unit mass (dU/(rho0 V0)) (uJ/g)
double workEnergy = 0.5*((st0.xx+sp->xx)*dvxx
+ (st0.yy+sp->yy)*dvyy
+ (st0.xy+sp->xy)*dgxy);
if(np==AXISYMMETRIC_MPM)
{ workEnergy += 0.5*(st0.zz+sp->zz)*dvzz;
}
// plastic strain work
double plastEnergy = lambdak*(sp->xx*dfds.xx + sp->yy*dfds.yy + sp->zz*dfds.zz + 2.*sp->xy*dfds.xy);
// total work
mptr->AddWorkEnergy(plastEnergy + workEnergy);
// disispated energy per unit mass (dPhi/(rho0 V0)) (uJ/g)
double qdalphaTerm = lambdak*SQRT_TWOTHIRDS*plasticLaw->GetYieldIncrement(mptr,np,delTime,&alpha,p->hardProps);
double dispEnergy = plastEnergy - qdalphaTerm;
// heat energy is Cv(dT-dTq0) - dPhi
// The dPhi is subtracted here because it will show up in next
// time step within Cv dT (if adibatic heating occurs)
// The Cv(dT-dTq0) was done in update pressure
IncrementHeatEnergy(mptr,0.,0.,dispEnergy);
// The cumulative dissipated energy is tracked in plastic energy
mptr->AddPlastEnergy(dispEnergy);
// update internal variables
plasticLaw->UpdatePlasticInternal(mptr,np,&alpha);
}
/* Take increments in strain and calculate new Particle: strains, rotation strain,
stresses, strain energy,
dvij are (gradient rates X time increment) to give deformation gradient change
For Axisymmetry: x->R, y->Z, z->theta, np==AXISYMMETRIC_MPM, otherwise dvzz=0
This material tracks pressure and stores deviatoric stress only in particle stress
tensor
*/
void Neohookean::MPMConstitutiveLaw(MPMBase *mptr,Matrix3 du,double delTime,int np,void *properties,
ResidualStrains *res,int historyOffset) const
{
// Update strains and rotations and Left Cauchy strain
double detDf = IncrementDeformation(mptr,du,NULL,np);
// get pointer to new left Cauchy strain
Tensor *B = mptr->GetAltStrainTensor();
// account for residual stresses
double dJres = GetIncrementalResJ(mptr,res);
double Jres = dJres*mptr->GetHistoryDble(J_History+1,historyOffset);
mptr->SetHistoryDble(J_History+1,Jres,historyOffset);
double resStretch = pow(Jres,1./3.);
double Jres23 = resStretch*resStretch;
// Deformation gradients and Cauchy tensor differ in plane stress
if(np==PLANE_STRESS_MPM)
{ // Find B->zz required to have zero stress in z direction
double arg = B->xx*B->yy - B->xy*B->xy;
double xn;
Tensor *ep=mptr->GetStrainTensor();
switch(UofJOption)
{ case J_MINUS_1_SQUARED:
{ double a = pr.Lamesp*arg + pr.Gsp*pow(Jres,4./3.);
double b = pr.Lamesp*sqrt(arg);
xn = Jres*(b + sqrt(b*b + 4.*pr.Gsp*a))/(2.*a);
xn *= xn;
break;
}
case LN_J_SQUARED:
{ xn = B->zz;
double fx,fxp,xnp1,Jres23 = pow(Jres,2./3.);
int iter=1;
while(iter<20)
{ // get f and df/dxn
fx = pr.Gsp*(xn-Jres23) + 0.5*pr.Lamesp*Jres23*log(xn*arg/(Jres*Jres));
fxp = pr.Gsp + pr.Lamesp*Jres23/(2*xn);
// new prediction for solution
xnp1 = xn - fx/fxp;
if(fabs(xn-xnp1)<1e-10) break;
xn = xnp1;
iter+=1;
}
break;
}
case HALF_J_SQUARED_MINUS_1_MINUS_LN_J:
default:
xn = Jres*Jres*(pr.Lamesp+2.*pr.Gsp)/(pr.Lamesp*arg+2.*pr.Gsp*pow(Jres,4./3.));
break;
}
// Done and xn = new B->zz = Fzz^2 = dFzz*(old Bzz)*dFzz = dFzz^2*(old Bzz),
// and Fzz = dFzz*(old Fzz) = 1 + ep->zz
//cout << xn << "," << pow(Jres,2./3.)*pr.Lamesp*(xn*arg/(Jres*Jres)-1.) + 2.*pr.Gsp*(xn-pow(Jres,2./3.)) << endl;;
double dFzz = sqrt(xn/B->zz);
B->zz = xn;
// particle strain ezz now known
ep->zz = dFzz*(1.+ep->zz) - 1.;
// incremental J changes
detDf *= dFzz;
}
// Increment J and save it in history data
double J = detDf*mptr->GetHistoryDble(J_History,historyOffset);
mptr->SetHistoryDble(J_History,J,historyOffset);
// for incremental energy, store initial stress
Tensor *sporig=mptr->GetStressTensor();
Tensor st0 = *sporig;
// account for residual stresses
double Jeff = J/Jres;
// update pressure
double p0=mptr->GetPressure();
double Pterm = J*GetVolumetricTerms(Jeff,pr.Lamesp) + Jres*pr.Gsp*((B->xx+B->yy+B->zz)/(3.*Jres23) - 1.);
// artifical viscosity
double delV = 1. - 1./detDf; // total volume change
double QAVred = 0.,AVEnergy=0.;
if(delV<0. && artificialViscosity)
{ QAVred = GetArtificalViscosity(delV/delTime,sqrt(pr.Ksp)*J);
if(ConductionTask::AVHeating) AVEnergy = fabs(QAVred*delV);
}
double Pfinal = -Pterm + QAVred;
// set the pressure
mptr->SetPressure(Pfinal);
// incremental energy - dilational part
double avgP = 0.5*(p0+Pfinal);
double dilEnergy = -avgP*delV;
// incremental residual energy
double delVres = 1. - 1./dJres;
double resEnergy = -avgP*delVres;
// Account for density change in specific stress
// i.e.. Get (Kirchoff Stress)/rho0
double GJeff = resStretch*pr.Gsp; // = J*(Jres^(1/3) G/J) to get Kirchoff
// find deviatoric (Cauchy stress)J/rho0 = deviatoric (Kirchoff stress)/rho0
Tensor *sp=mptr->GetStressTensor();
double I1third = (B->xx+B->yy+B->zz)/3.;
sp->xx = GJeff*(B->xx-I1third);
sp->yy = GJeff*(B->yy-I1third);
sp->zz = GJeff*(B->zz-I1third);
sp->xy = GJeff*B->xy;
if(np==THREED_MPM)
{ sp->xz = GJeff*B->xz;
sp->yz = GJeff*B->yz;
}
// incremental work energy = shear energy
double shearEnergy = 0.5*((sp->xx+st0.xx)*du(0,0) + (sp->yy+st0.yy)*du(1,1) + (sp->zz+st0.zz)*du(2,2)+
(sp->xy+st0.xy)*(du(0,1)+du(1,0)));
if(np==THREED_MPM)
{ shearEnergy += 0.5*((sp->xz+st0.xz)*(du(0,2)+du(2,0)) + (sp->yz+st0.yz)*(du(1,2)+du(2,1)));
}
// strain energy
double dU = dilEnergy + shearEnergy;
mptr->AddWorkEnergyAndResidualEnergy(dU,resEnergy);
// particle isentropic temperature increment
double Kratio; // = rho_0 K/(rho K_0)
double Jeff1third = pow(Jeff,1./3.);
double Gterm = pr.Gsp*(1. - Jeff1third*Jeff1third + 2./(3.*Jeff1third));
switch(UofJOption)
{ case J_MINUS_1_SQUARED:
Kratio = pr.Lamesp+Jeff + Gterm;
break;
case LN_J_SQUARED:
Kratio = pr.Lamesp*(1-log(Jeff))/(Jeff*Jeff) + Gterm;
break;
case HALF_J_SQUARED_MINUS_1_MINUS_LN_J:
default:
Kratio = 0.5*(Jeff + 1./Jeff);
break;
}
Kratio /= pr.Ksp;
double dTq0 = -J*Kratio*gamma0*mptr->pPreviousTemperature*delV;
// thermodynamics heat and temperature
IncrementHeatEnergy(mptr,res->dT,dTq0,QAVred);
}
/* Take increments in strain and calculate new Particle: strains, rotation strain, plastic strain,
stresses, strain energy, plastic energy, dissipated energy, angle
dvij are (gradient rates X time increment) to give deformation gradient change
For Axisymmetry: x->R, y->Z, z->theta, np==AXISYMMETRIC_MPM, otherwise dvzz=0
This material tracks pressure and stores deviatoric stress only in particle stress tensor
*/
void Viscoelastic::MPMConstitutiveLaw(MPMBase *mptr,Matrix3 du,double delTime,int np,void *properties,ResidualStrains *res) const
{
// Effective strain by deducting thermal strain (no shear thermal strain because isotropic)
double eres=CTE*res->dT;
if(DiffusionTask::active)
eres+=CME*res->dC;
// update pressure
double delV = du.trace() - 3.*eres;
UpdatePressure(mptr,delV,res,eres);
// deviatoric strains increment
// Actually find 2*de to avoid many multiples by two
Tensor de;
double dV = du.trace()/3.;
de.xx = 2.*(du(0,0) - dV);
de.yy = 2.*(du(1,1) - dV);
de.zz = 2.*(du(2,2) - dV);
de.xy = du(0,1)+du(1,0);
if(np==THREED_MPM)
{ de.xz = du(0,2)+du(2,0);
de.yz = du(1,2)+du(2,1);
}
// Find initial 2*e(t) in ed
Tensor *ep=mptr->GetStrainTensor();
Tensor ed = *ep;
double thirdV = (ed.xx+ed.yy+ed.zz)/3.;
ed.xx = 2.*(ed.xx-thirdV);
ed.yy = 2.*(ed.yy-thirdV);
ed.zz = 2.*(ed.zz-thirdV);
// Increment total strains on the particle
ep->xx += du(0,0);
ep->yy += du(1,1);
ep->zz += du(2,2);
ep->xy += de.xy;
if(np==THREED_MPM)
{ ep->xz += de.xz;
ep->yz += de.yz;
}
// get internal variable increments and update them too
Tensor dak;
double **ak =(double **)(mptr->GetHistoryPtr());
int k;
for(k=0;k<ntaus;k++)
{ double tmp = exp(-delTime/tauk[k]);
double tmpm1 = tmp-1.;
double tmpp1 = tmp+1.;
double arg = 0.25*delTime/tauk[k]; // 0.25 because e's have factor of 2
dak.xx = tmpm1*ak[XX_HISTORY][k] + arg*(tmpp1*ed.xx + de.xx);
dak.yy = tmpm1*ak[YY_HISTORY][k] + arg*(tmpp1*ed.yy + de.yy);
dak.xy = tmpm1*ak[XY_HISTORY][k] + arg*(tmpp1*ed.xy + de.xy);
dak.zz = tmpm1*ak[ZZ_HISTORY][k] + arg*(tmpp1*ed.zz + de.zz);
ak[XX_HISTORY][k] += dak.xx;
ak[YY_HISTORY][k] += dak.yy;
ak[ZZ_HISTORY][k] += dak.zz;
ak[XY_HISTORY][k] += dak.xy;
if(np==THREED_MPM)
{ dak.xz = tmpm1*ak[XZ_HISTORY][k] + arg*(tmpp1*ed.xz + de.xz);
dak.yz = tmpm1*ak[YZ_HISTORY][k] + arg*(tmpp1*ed.yz + de.yz);
ak[XZ_HISTORY][k] += dak.xz;
ak[YZ_HISTORY][k] += dak.yz;
}
}
// increment particle deviatoric stresses
double dsig[6];
dsig[XX] = Gered*de.xx;
dsig[YY] = Gered*de.yy;
dsig[ZZ] = Gered*de.zz;
dsig[XY] = Gered*de.xy;
if(np==THREED_MPM)
{ dsig[XZ] = Gered*de.xz;
dsig[YZ] = Gered*de.yz;
}
for(k=0;k<ntaus;k++)
{ dsig[XX] -= TwoGkred[k]*dak.xx;
dsig[YY] -= TwoGkred[k]*dak.yy;
dsig[ZZ] -= TwoGkred[k]*dak.zz;
dsig[XY] -= TwoGkred[k]*dak.xy;
if(np==THREED_MPM)
{ dsig[XZ] -= TwoGkred[k]*dak.xz;
dsig[YZ] -= TwoGkred[k]*dak.yz;
}
}
// Hypoelastic increment of particle deviatoric stresses
Tensor *sp=mptr->GetStressTensor();
Tensor st0 = *sp;
double dwrotxy = du(1,0)-du(0,1);
if(np==THREED_MPM)
{ double dwrotxz = du(2,0)-du(0,2);
double dwrotyz = du(2,1)-du(1,2);
Hypo3DCalculations(mptr,dwrotxy,dwrotxz,dwrotyz,dsig);
}
else
{ Hypo2DCalculations(mptr,-dwrotxy,dsig[XX],dsig[YY],dsig[XY]);
sp->zz += dsig[ZZ];
}
// incremental work energy = shear energy (dilation and residual energy done in update pressure)
double shearEnergy = 0.5*((sp->xx+st0.xx)*du(0,0) + (sp->yy+st0.yy)*du(1,1) + (sp->zz+st0.zz)*du(2,2)+
(sp->xy+st0.xy)*de.xy);
if(np==THREED_MPM)
{ shearEnergy += 0.5*((sp->xz+st0.xz)*de.xz + (sp->yz+st0.yz)*de.yz);
}
mptr->AddWorkEnergyAndResidualEnergy(shearEnergy,0.);
// disispated energy per unit mass (dPhi/(rho0 V0)) (uJ/g)
double dispEnergy = 0.;
for(k=0;k<ntaus;k++)
{ dispEnergy += TwoGkred[k]*(dak.xx*(0.5*(ed.xx+0.5*de.xx)-ak[XX_HISTORY][k]+0.5*dak.xx)
+ dak.yy*(0.5*(ed.yy+0.5*de.yy)-ak[YY_HISTORY][k]+0.5*dak.yy)
+ dak.zz*(0.5*(ed.zz+0.5*de.zz)-ak[ZZ_HISTORY][k]+0.5*dak.zz)
+ dak.xy*(0.5*(ed.xy+0.5*de.xy)-ak[XY_HISTORY][k]+0.5*dak.xy));
if(np==THREED_MPM)
{ dispEnergy += TwoGkred[k]*(dak.xz*(0.5*(ed.xz+0.5*de.xz)-ak[XZ_HISTORY][k]+0.5*dak.xz)
+ dak.yz*(0.5*(ed.yz+0.5*de.yz)-ak[YZ_HISTORY][k]+0.5*dak.yz));
}
}
mptr->AddPlastEnergy(dispEnergy);
// heat energy is Cv dT - dPhi
// The dPhi is subtracted here because it will show up in next
// time step within Cv dT (if adibatic heating occurs)
// The Cv dT was done in update pressure
IncrementHeatEnergy(mptr,0.,0.,dispEnergy);
}
/* For 3D MPM analysis, take increments in strain and calculate new
Particle: strains, rotation strain, stresses, strain energy, angle
dvij are (gradient rates X time increment) to give deformation gradient change
Assumes linear elastic, uses hypoelastic correction
*/
void Elastic::MPMConstLaw(MPMBase *mptr,double dvxx,double dvyy,double dvzz,double dvxy,double dvyx,
double dvxz,double dvzx,double dvyz,double dvzy,double delTime,int np,void *properties,ResidualStrains *res) const
{
// cast pointer to material-specific data
ElasticProperties *p = (ElasticProperties *)properties;
// Add to total strain
Tensor *ep = mptr->GetStrainTensor();
ep->xx += dvxx;
ep->yy += dvyy;
ep->zz += dvzz;
double dgamxy = dvxy+dvyx;
ep->xy += dgamxy;
double dgamxz = dvxz+dvzx;
ep->xz += dgamxz;
double dgamyz = dvyz+dvzy;
ep->yz += dgamyz;
// rotational strain increments (particle updated by Hypo3D)
double dwrotxy = dvyx-dvxy;
double dwrotxz = dvzx-dvxz;
double dwrotyz = dvzy-dvyz;
// residual strains (thermal and moisture) (isotropic only)
double exxr = p->alpha[0]*res->dT;
double eyyr = p->alpha[1]*res->dT;
double ezzr = p->alpha[2]*res->dT;
double eyzr = p->alpha[3]*res->dT;
double exzr = p->alpha[4]*res->dT;
double exyr = p->alpha[5]*res->dT;
if(DiffusionTask::active)
{ exxr += p->beta[0]*res->dC;
eyyr += p->beta[1]*res->dC;
ezzr += p->beta[2]*res->dC;
eyzr += p->beta[3]*res->dC;
exzr += p->beta[4]*res->dC;
exyr += p->beta[5]*res->dC;
}
// effective strains
double dvxxeff = dvxx-exxr;
double dvyyeff = dvyy-eyyr;
double dvzzeff = dvzz-ezzr;
double dgamyzeff = dgamyz-eyzr;
double dgamxzeff = dgamxz-exzr;
double dgamxyeff = dgamxy-exyr;
// save initial stresses
Tensor *sp=mptr->GetStressTensor();
Tensor st0=*sp;
// stress increments
double delsp[6];
int i;
for(i=0;i<6;i++)
{ delsp[i] = p->C[i][0]*dvxxeff + p->C[i][1]*dvyyeff + p->C[i][2]*dvzzeff
+ p->C[i][3]*dgamyzeff + p->C[i][4]*dgamxzeff + p->C[i][5]*dgamxyeff;
}
// update stress (need to make hypoelastic)
Hypo3DCalculations(mptr,dwrotxy,dwrotxz,dwrotyz,delsp);
// work energy increment per unit mass (dU/(rho0 V0))
mptr->AddWorkEnergyAndResidualEnergy(
0.5*((st0.xx+sp->xx)*dvxx + (st0.yy+sp->yy)*dvyy
+ (st0.zz+sp->zz)*dvzz + (st0.yz+sp->yz)*dgamyz
+ (st0.xz+sp->xz)*dgamxz + (st0.xy+sp->xy)*dgamxy),
0.5*((st0.xx+sp->xx)*exxr + (st0.yy+sp->yy)*eyyr
+ (st0.zz+sp->zz)*ezzr + (st0.yz+sp->yz)*eyzr
+ (st0.xz+sp->xz)*exzr + (st0.xy+sp->xy)*exyr));
// track heat energy
IncrementHeatEnergy(mptr,res->dT,0.,0.);
}
// Apply Constitutive law, check np to know what type
void TaitLiquid::MPMConstitutiveLaw(MPMBase *mptr,Matrix3 du,double delTime,int np,void *properties,ResidualStrains *res) const
{
#ifdef NO_SHEAR_MODEL
// get incremental deformation gradient
const Matrix3 dF = du.Exponential(incrementalDefGradTerms);
// decompose dF into dR and dU
Matrix3 dR;
Matrix3 dU = dF.RightDecompose(&dR,NULL);
// current deformation gradient
double detdF = dF.determinant();
Matrix3 pF = mptr->GetDeformationGradientMatrix();
Matrix3 F = dR*pF;
if(np==THREED_MPM)
F.Scale(pow(detdF,1./3.));
else
F.Scale2D(sqrt(detdF));
// new deformation matrix with volume change onle
mptr->SetDeformationGradientMatrix(F);
#else
// Update total deformation gradient, and calculate trial B
double detdF = IncrementDeformation(mptr,du,NULL,np);
#endif
// Get new J and save result on the particle
double J = detdF * mptr->GetHistoryDble(J_history);
mptr->SetHistoryDble(J_history,J);
// account for residual stresses
double dresStretch,resStretch = GetResidualStretch(mptr,dresStretch,res);
double Jres = resStretch*resStretch*resStretch;
double Jeff = J/Jres;
// new Kirchhoff pressure (over rho0) from Tait equation
double p0=mptr->GetPressure();
double pressure = J*TAIT_C*Ksp*(exp((1.-Jeff)/TAIT_C)-1.);
mptr->SetPressure(pressure);
// incremental energy per unit mass - dilational part
double avgP = 0.5*(p0+pressure);
double delV = 1. - 1./detdF;
double workEnergy = -avgP*delV;
// incremental residual energy per unit mass
double delVres = 1. - 1./(dresStretch*dresStretch*dresStretch);
double resEnergy = -avgP*delVres;
// viscosity term = 2 eta (0.5(grad v) + 0.5*(grad V)^T - (1/3) tr(grad v) I)
// (i.e., divatoric part of the symmetric strain tensor, 2 is for conversion to engineering shear strain)
Matrix3 shear;
double c[3][3];
c[0][0] = (2.*du(0,0)-du(1,1)-du(2,2))/3.;
c[1][1] = (2.*du(1,1)-du(0,0)-du(2,2))/3.;
c[2][2] = (2.*du(2,2)-du(0,0)-du(1,1))/3.;
c[0][1] = 0.5*(du(0,1)+du(1,0));
c[1][0] = c[0][1];
if(np==THREED_MPM)
{ c[0][2] = 0.5*(du(0,2)+du(2,0));
c[2][0] = c[0][2];
c[1][2] = 0.5*(du(1,2)+du(2,1));
c[2][1] = c[1][2];
shear.set(c);
}
else
shear.set(c[0][0],c[0][1],c[1][0],c[1][1],c[2][2]);
// Get Kirchoff shear stress (over rho0)
shear.Scale(J*TwoEtasp/delTime);
// update deviatoric stress
Tensor *sp=mptr->GetStressTensor();
sp->xx = shear(0,0);
sp->yy = shear(1,1);
sp->zz = shear(2,2);
sp->xy = shear(0,1);
if(np==THREED_MPM)
{ sp->xz = shear(0,2);
sp->yz = shear(1,2);
}
// shear work per unit mass = tau.du = tau.tau*delTime/TwoEtasp
double shearWork = sp->xx*sp->xx + sp->yy*sp->yy + sp->zz*sp->zz + 2.*sp->xy*sp->xy;
if(np==THREED_MPM) shearWork += 2.*(sp->xz*sp->xz + sp->yz*sp->yz);
shearWork *= delTime/TwoEtasp;
mptr->AddWorkEnergyAndResidualEnergy(workEnergy+shearWork,resEnergy);
// particle isentropic temperature increment dT/T = - J (K/K0) gamma0 Delta(V)/V
// Delta(V)/V = 1. - 1/detdF (total volume)
double Kratio = Jeff*(1.+pressure/(TAIT_C*Ksp));
double dTq0 = -J*Kratio*gamma0*mptr->pPreviousTemperature*delV;
// heat energy is Cv (dT - dTq0) -dPhi
// Here do Cv (dT - dTq0)
// dPhi = shearWork is lost due to shear term
IncrementHeatEnergy(mptr,res->dT,dTq0,shearWork);
}
// This method handles the pressure equation of state. Its tasks are
// 1. Calculate the new pressure
// 2. Update particle pressure
// 3. Increment the particle energy due to dilation
// 4. Call plasticLaw to see if it wants to change the shear modulus
// J = V(T,c)/V0(T,c), Jeff = V(T,c)/V0(Tref,cref), Jres = V0(T,c)/V0(Tref,cref) = J/Jeff
// Jtot = V(T,c)/V0(Trec,cref), Jres = V0(T,c)/V0(Tref,cref) for free expansion, J = V(T,c)/V0(T,c)
// Jn+1 = (detdF/detdFres) Jn, Jresn+1 = detdFres Jresn, Jtot = detdF Jtotn
// detdFres = (1+dres)^3 (approximately)
// Here Tref and cref are starting conditions and T and c are current temperature and moisture
void HEMGEOSMaterial::UpdatePressure(MPMBase *mptr,double J,double detdF,int np,double Jeff,
double delTime,HEPlasticProperties *p,ResidualStrains *res,double detdFres) const
{
// J is total volume change - may need to reference to free-swelling volume if that works
// Note that swelling looks like a problem because the sums of strains needs to be adjusted
// to stress-free state
// previous pressure
double P,P0 = mptr->GetPressure();
double delV = 1. - 1./detdF;
double dTq0;
// M-G EOS
// Want specific pressure or pressure over current density (using J = rho0/rho)
if(J>1.)
{ // new compression J(k+1) = 1-x(k+1)
double x = 1.-J;
// compression law
// denominator = 1 - S1*x - S2*x^2 - S3*x^3
double denom = 1./(1. - x*(S1 + x*(S2 + x*S3)));
// law not valid if denominator passes zero
if(denom<0)
{ cout << "# Excessive x = " << x << endl;
mptr->Describe();
}
// current effective and reduced (by rho0) bulk modulus
p->Kred = C0squared*(1.-0.5*gamma0*x)*denom*denom;
// Pressure from bulk modulus and an energy term
double e = mptr->GetInternalEnergy();
P = J*(p->Kred*x + gamma0*e);
// particle isentropic temperature increment
dTq0 = -J*gamma0*mptr->pPreviousTemperature*delV;
}
else
{ // In tension hyperelastic law P = - K0(J-1)
p->Kred = C0squared*Jeff;
P = -J*C0squared*(Jeff-1.);
//P = P0 - J*p->Kred*delV;
// particle isentropic temperature increment
double Kratio = Jeff;
dTq0 = -J*Kratio*gamma0*mptr->pPreviousTemperature*delV;
}
// artifical viscosity
// delV is total incremental volumetric strain = total Delta(V)/V
double QAVred = 0.,AVEnergy=0.;
if(delV<0. && artificialViscosity)
{ double c = sqrt(p->Kred*J/1000.); // m/sec
QAVred = GetArtificalViscosity(delV/delTime,c);
if(ConductionTask::AVHeating) AVEnergy = fabs(QAVred*delV);
}
// set final pressure
mptr->SetPressure(P+QAVred);
// work energy is dU = -P dV + s.de(total)
// Here do hydrostatic terms, deviatoric later
double avgP = 0.5*(P0+P);
double delVres = 1. - 1./detdFres;
mptr->AddWorkEnergyAndResidualEnergy(-avgP*delV,-avgP*delVres);
// heat energy is Cv (dT - dTq0) - dPhi - |QAVred*delV|
// Here do Cv (dT - dTq0) - |QAVred*delV| term and dPhi is done later
IncrementHeatEnergy(mptr,res->dT,dTq0,AVEnergy);
// SCGL and SL shear modulus and save Gratio = Jeff G/G0 for later calculations
// Note: Jeff in Gred and Gratio is so that where they are used, they give
// specific Cauchy stress
p->Gred = G1sp * plasticLaw->GetShearRatio(mptr,avgP,Jeff,p->hardProps);
}
/* Take increments in strain and calculate new Particle: strains, rotation strain,
stresses, strain energy,
dvij are (gradient rates X time increment) to give deformation gradient change
For Axisymmetry: x->R, y->Z, z->theta, np==AXISYMMETRIC_MPM, otherwise dvzz=0
This material tracks pressure and stores deviatoric stress only in particle stress
tensor
*/
void Mooney::MPMConstitutiveLaw(MPMBase *mptr,Matrix3 du,double delTime,int np,void *properties,
ResidualStrains *res,int historyOffset) const
{
// incremental energy, store initial stress
Tensor *sporig=mptr->GetStressTensor();
Tensor st0 = *sporig;
// Update strains and rotations and Left Cauchy strain
double detDf = IncrementDeformation(mptr,du,NULL,np);
// get pointer to new left Cauchy strain
Tensor *B = mptr->GetAltStrainTensor();
// account for residual stresses
double dJres = GetIncrementalResJ(mptr,res);
double Jres = dJres*mptr->GetHistoryDble(J_History+1,historyOffset);
mptr->SetHistoryDble(J_History+1,Jres,historyOffset);
// Deformation gradients and Cauchy tensor differ in plane stress
if(np==PLANE_STRESS_MPM)
{ // Find B->zz required to have zero stress in z direction
// fixed arguments
double arg = B->xx*B->yy - B->xy*B->xy;
double arg12 = sqrt(arg);
double arg16 = pow(arg,1./6.);
double arg2 = B->xx+B->yy;
// Newton-Rapheson starting at B.zz = 1
// In tests finds answer in 3 or less steps
Tensor *ep=mptr->GetStrainTensor();
double xn16,xn12,xnp1,xn = (1.+ep->zz)*(1.+ep->zz);
double fx,fxp,J13,J0,J2,Jeff;
int iter=1;
double mJ2P,mdJ2PdJ;
// solution for B.zz in xn and J = sqrt(xn*arg) with dJ/dxn = arg/(2 sqrt(xn*arg))
// Solving f=0 where f = 3J^2 Kterm + Jres*G1(2*xn-arg2)J^(1/3) + Jres*G2(xn*arg2 - 2*arg)/J^(1/3)
// where J^(1/3) = (xn*arg)^(1/6)
// df/dxn = d(3J^2 Kterm)/dJ dJ/dxn
// + Jres*G1((14*xn-arg2)/(6*xn))J^(1/3)
// + Jres*G2((5*xn*arg2+2*arg)/(6*xn))/J^(1/3)
while(iter<20)
{ xn16 = pow(xn,1./6.);
xn12 = sqrt(xn);
J13 = xn16*arg16;
J0 = xn12*arg12;
J2 = J0*J0;
Jeff = J0/Jres;
// get f and df/dxn
GetNewtonPressureTerms(Jeff, Ksp, mJ2P, mdJ2PdJ);
fx = 3.*Jres*mJ2P + G1sp*(2.*xn-arg2)*J13 + G2sp*(xn*arg2-2.*arg)/J13;
fxp = (1.5*J0/xn)*mdJ2PdJ + G1sp*J13*(14.*xn-arg2)/(6.*xn) + G2sp*(2.*arg+5.*xn*arg2)/(6.*J13*xn);
// new prediction for solution
xnp1 = xn - fx/fxp;
//cout << iter << ": " << xn << "," << xnp1 << "," << fabs(xn-xnp1) << endl;
if(fabs(xn-xnp1)<1e-10) break;
xn = xnp1;
iter+=1;
}
if(iter>=20) cout << "# Not enough iterations in plane stress Mooney-Rivlin material" << endl;
// Done and xn = new B->zz = Fzz^2 = dFzz*(old Bzz)*dFzz = dFzz^2*(old Bzz),
// and Fzz = dFzz*(old Fzz) = 1 + ep->zz
double dFzz = sqrt(xn/B->zz);
B->zz = xn;
// particle strain ezz now known
ep->zz = dFzz*(1.+ep->zz) - 1.;
// incremental J changes
detDf *= dFzz;
}
// Increment J and save it in history data
double J = detDf*mptr->GetHistoryDble(J_History,historyOffset);
mptr->SetHistoryDble(J_History,J,historyOffset);
// account for residual stresses
double Jeff = J/Jres;
// update pressure
double p0=mptr->GetPressure();
double Kterm = J*GetVolumetricTerms(Jeff,Ksp); // times J to get Kirchoff stress
// artifical viscosity
double delV = 1. - 1./detDf; // total volume change
double QAVred = 0.,AVEnergy=0.;
if(delV<0. && artificialViscosity)
{ QAVred = GetArtificalViscosity(delV/delTime,sqrt(Ksp*J),mptr);
if(ConductionTask::AVHeating) AVEnergy = fabs(QAVred*delV);
}
double Pfinal = -Kterm + QAVred;
// set the pressure
mptr->SetPressure(Pfinal);
// incremental energy - dilational part
double avgP = 0.5*(p0+Pfinal);
double dilEnergy = -avgP*delV;
// incremental residual energy
double delVres = 1. - 1./dJres;
double resEnergy = -avgP*delVres;
// Account for density change in specific stress
// i.e.. Get (Cauchy Stress)/rho = J*(Cauchy Stress)/rho0 = (Kirchoff Stress)/rho0
double J23 = pow(J, 2./3.);
double J43 = J23*J23;
double JforG1 = J23/Jres; // J^(5/3)/(Jres J) = J^(2/3)/Jres to get Kirchoff stress
double JforG2 = J43/Jres; // J^(7/3)/(Jres J) = J^(4/3)/Jres to get Kirchoff stress
//JforG1 *= Jres; // this uses Jeff to get Kirchoff stress
//JforG2 *= Jres; // this uses Jeff to get Kirchoff stress
// find deviatoric (Cauchy stress)J/rho0 = deviatoric (Kirchoff stress)/rho0
Tensor *sp=mptr->GetStressTensor();
sp->xx = (2*B->xx-B->yy-B->zz)*G1sp/(3.*JforG1)
+ (B->xx*(B->yy+B->zz)-2*B->yy*B->zz-B->xy*B->xy)*G2sp/(3.*JforG2);
sp->yy = (2*B->yy-B->xx-B->zz)*G1sp/(3.*JforG1)
+ (B->yy*(B->xx+B->zz)-2*B->xx*B->zz-B->xy*B->xy)*G2sp/(3.*JforG2);
sp->zz = (2*B->zz-B->xx-B->yy)*G1sp/(3.*JforG1)
+ (B->zz*(B->xx+B->yy)-2*B->xx*B->yy+2.*B->xy*B->xy)*G2sp/(3.*JforG2);
sp->xy = B->xy*G1sp/JforG1 + (B->zz*B->xy)*G2sp/JforG2;
if(np==THREED_MPM)
{ sp->xx += (2.*B->yz*B->yz-B->xz*B->xz)*G2sp/(3.*JforG2);
sp->yy += (2.*B->xz*B->xz-B->yz*B->yz)*G2sp/(3.*JforG2);
sp->zz -= (B->xz*B->xz+B->yz*B->yz)*G2sp/(3.*JforG2);
sp->xy -= B->xz*B->yz*G2sp/JforG2;
sp->xz = B->xz*G1sp/JforG1 + (B->yy*B->xz-B->xy*B->yz)*G2sp/JforG2;
sp->yz = B->yz*G1sp/JforG1 + (B->xx*B->yz-B->xy*B->xz)*G2sp/JforG2;
}
// incremental work energy = shear energy
double shearEnergy = 0.5*((sp->xx+st0.xx)*du(0,0) + (sp->yy+st0.yy)*du(1,1) + (sp->zz+st0.zz)*du(2,2)+
(sp->xy+st0.xy)*(du(0,1)+du(1,0)));
if(np==THREED_MPM)
{ shearEnergy += 0.5*((sp->xz+st0.xz)*(du(0,2)+du(2,0)) + (sp->yz+st0.yz)*(du(1,2)+du(2,1)));
}
// strain energy
double dU = dilEnergy + shearEnergy;
mptr->AddWorkEnergyAndResidualEnergy(dU,resEnergy);
// thermodynamics depends on whether or not this is a rubber
double dTq0;
if(rubber)
{ // convert internal energy to temperature change
dTq0 = dU/GetHeatCapacity(mptr);
}
else
{ // elastic particle isentropic temperature increment
double Kratio; // = rho_0 K/(rho K_0)
switch(UofJOption)
{ case J_MINUS_1_SQUARED:
Kratio = Jeff;
break;
case LN_J_SQUARED:
Kratio = (1-log(Jeff))/(Jeff*Jeff);
break;
case HALF_J_SQUARED_MINUS_1_MINUS_LN_J:
default:
Kratio = 0.5*(Jeff + 1./Jeff);
break;
}
dTq0 = -J*Kratio*gamma0*mptr->pPreviousTemperature*delV;
}
IncrementHeatEnergy(mptr,res->dT,dTq0,QAVred);
}
/* Take increments in strain and calculate new Particle: strains, rotation strain,
stresses, strain energy,
du are (gradient rates X time increment) to give deformation gradient change
For Axisymmetry: x->R, y->Z, z->theta, np==AXISYMMETRIC_MPM, otherwise dvzz=0
This material tracks pressure and stores deviatoric stress only in particle stress tensor
*/
void Viscoelastic::MPMConstitutiveLaw(MPMBase *mptr,Matrix3 du,double delTime,int np,void *properties,ResidualStrains *res,int historyOffset) const
{
// current previous deformation gradient and stretch
Matrix3 pFnm1 = mptr->GetDeformationGradientMatrix();
// get incremental deformation gradient and decompose it
const Matrix3 dF = du.Exponential(incrementalDefGradTerms);
Matrix3 dR;
Matrix3 dVstretch = dF.LeftDecompose(&dR,NULL);
// decompose to get previous stretch
Matrix3 Vnm1 = pFnm1.LeftDecompose(NULL,NULL);
// get strain increments de = (dV-I) dR Vnma dRT
dVstretch(0,0) -= 1.;
dVstretch(1,1) -= 1.;
dVstretch(2,2) -= 1.;
Matrix3 Vrot = Vnm1.RMRT(dR);
Matrix3 detot = dVstretch*Vrot;
// Update total deformation gradient
Matrix3 pF = dF*pFnm1;
mptr->SetDeformationGradientMatrix(pF);
// Effective strain by deducting thermal strain (no shear thermal strain because isotropic)
double eres=CTE*res->dT;
if(DiffusionTask::active)
eres+=CME*res->dC;
// update pressure
double dTq0 = 0.,dispEnergy = 0.;
double traceDe = detot.trace();
double delV = traceDe - 3.*eres;
#ifdef USE_KIRCHOFF_STRESS
// tracking J
double detdF = dF.determinant();
double **h =(double **)(mptr->GetHistoryPtr(0));
double J = detdF*h[mptrHistory][MGJ_HISTORY];
h[mptrHistory][MGJ_HISTORY] = J;
UpdatePressure(mptr,delV,res,eres,detdF,J,delTime,dTq0,dispEnergy);
#else
UpdatePressure(mptr,delV,res,eres,&dF,delTime,dTq0,dispEnergy);
#endif
// deviatoric strains increment in de
// Actually de is finding 2*(dev e) to avoid many multiplies by two
Tensor de;
double dV = traceDe/3.;
de.xx = 2.*(detot(0,0) - dV);
de.yy = 2.*(detot(1,1) - dV);
de.zz = 2.*(detot(2,2) - dV);
de.xy = 2.*detot(0,1);
if(np==THREED_MPM)
{ de.xz = 2.*detot(0,2);
de.yz = 2.*detot(1,2);
}
// Find initial 2*e(t) (deviatoric strain) in ed
Tensor ed;
double thirdV = Vrot.trace()/3.;
ed.xx = 2.*(Vrot(0,0)-thirdV);
ed.yy = 2.*(Vrot(1,1)-thirdV);
ed.zz = 2.*(Vrot(2,2)-thirdV);
ed.xy = 2.*Vrot(0,1);
if(np==THREED_MPM)
{ ed.xz = 2.*Vrot(0,2);
ed.yz = 2.*Vrot(1,2);
}
// increment particle deviatoric stresses - elastic part
double dsig[6];
dsig[XX] = Gered*de.xx;
dsig[YY] = Gered*de.yy;
dsig[ZZ] = Gered*de.zz;
dsig[XY] = Gered*de.xy;
if(np==THREED_MPM)
{ dsig[XZ] = Gered*de.xz;
dsig[YZ] = Gered*de.yz;
}
// get internal variable increments, update them, add to incremental stress, and get dissipated energy6
Tensor dak;
double **ak =(double **)(mptr->GetHistoryPtr(0));
int k;
for(k=0;k<ntaus;k++)
{ double tmp = exp(-delTime/tauk[k]);
double tmpm1 = tmp-1.;
double tmpp1 = tmp+1.;
double arg = 0.25*delTime/tauk[k]; // 0.25 because e's have factor of 2
dak.xx = tmpm1*ak[XX_HISTORY][k] + arg*(tmpp1*ed.xx + de.xx);
dak.yy = tmpm1*ak[YY_HISTORY][k] + arg*(tmpp1*ed.yy + de.yy);
dak.xy = tmpm1*ak[XY_HISTORY][k] + arg*(tmpp1*ed.xy + de.xy);
dak.zz = tmpm1*ak[ZZ_HISTORY][k] + arg*(tmpp1*ed.zz + de.zz);
ak[XX_HISTORY][k] += dak.xx;
ak[YY_HISTORY][k] += dak.yy;
ak[ZZ_HISTORY][k] += dak.zz;
ak[XY_HISTORY][k] += dak.xy;
// add to stress increments
dsig[XX] -= TwoGkred[k]*dak.xx;
dsig[YY] -= TwoGkred[k]*dak.yy;
dsig[ZZ] -= TwoGkred[k]*dak.zz;
dsig[XY] -= TwoGkred[k]*dak.xy;
// dissipation
dispEnergy += TwoGkred[k]*(dak.xx*(0.5*(ed.xx+0.5*de.xx)-ak[XX_HISTORY][k]+0.5*dak.xx)
+ dak.yy*(0.5*(ed.yy+0.5*de.yy)-ak[YY_HISTORY][k]+0.5*dak.yy)
+ dak.zz*(0.5*(ed.zz+0.5*de.zz)-ak[ZZ_HISTORY][k]+0.5*dak.zz)
+ dak.xy*(0.5*(ed.xy+0.5*de.xy)-ak[XY_HISTORY][k]+0.5*dak.xy));
// extra terms for 3D
if(np==THREED_MPM)
{ // internal variables
dak.xz = tmpm1*ak[XZ_HISTORY][k] + arg*(tmpp1*ed.xz + de.xz);
dak.yz = tmpm1*ak[YZ_HISTORY][k] + arg*(tmpp1*ed.yz + de.yz);
ak[XZ_HISTORY][k] += dak.xz;
ak[YZ_HISTORY][k] += dak.yz;
// stresses
dsig[XZ] -= TwoGkred[k]*dak.xz;
dsig[YZ] -= TwoGkred[k]*dak.yz;
// dissipation
dispEnergy += TwoGkred[k]*(dak.xz*(0.5*(ed.xz+0.5*de.xz)-ak[XZ_HISTORY][k]+0.5*dak.xz)
+ dak.yz*(0.5*(ed.yz+0.5*de.yz)-ak[YZ_HISTORY][k]+0.5*dak.yz));
}
}
// Update particle deviatoric stresses
Tensor *sp=mptr->GetStressTensor();
//Tensor st0 = *sp;
if(np==THREED_MPM)
{ // incremental rotate of prior stress
Matrix3 stn(sp->xx,sp->xy,sp->xz,sp->xy,sp->yy,sp->yz,sp->xz,sp->yz,sp->zz);
Matrix3 str = stn.RMRT(dR);
#ifdef USE_KIRCHOFF_STRESS
// convert sigma(n)/rho(n) to sigma(n)/rho(n+1) and add dsigma/rho(n+1)
sp->xx = detdF*str(0,0)+J*dsig[XX];
sp->yy = detdF*str(1,1)+J*dsig[YY];
sp->xy = detdF*str(0,1)+J*dsig[XY];
sp->zz = detdF*str(2,2)+J*dsig[ZZ];
sp->yz = detdF*str(1,2)+J*dsig[YZ];
sp->xz = detdF*str(0,2)+J*dsig[XZ];
#else
sp->xx = str(0,0)+dsig[XX];
sp->yy = str(1,1)+dsig[YY];
sp->xy = str(0,1)+dsig[XY];
sp->zz = str(2,2)+dsig[ZZ];
sp->yz = str(1,2)+dsig[YZ];
sp->xz = str(0,2)+dsig[XZ];
#endif
}
else
{ // incremental rotate of prior stress
Matrix3 stn(sp->xx,sp->xy,sp->xy,sp->yy,sp->zz);
Matrix3 str = stn.RMRT(dR);
#ifdef USE_KIRCHOFF_STRESS
// convert sigma(n)/rho(n) to sigma(n)/rho(n+1) and add dsigma/rho(n+1)
sp->xx = detdF*str(0,0)+J*dsig[XX];
sp->yy = detdF*str(1,1)+J*dsig[YY];
sp->xy = detdF*str(0,1)+J*dsig[XY];
sp->zz = detdF*sp->zz+J*dsig[ZZ];
#else
sp->xx = str(0,0)+dsig[XX];
sp->yy = str(1,1)+dsig[YY];
sp->xy = str(0,1)+dsig[XY];
sp->zz += dsig[ZZ];
#endif
}
// incremental work energy = shear energy (dilation and residual energy done in update pressure)
double shearEnergy = sp->xx*detot(0,0) + sp->yy*detot(1,1) + sp->zz*detot(2,2) + sp->xy*de.xy;
if(np==THREED_MPM)
{ shearEnergy += sp->xz*de.xz + sp->yz*de.yz;
}
mptr->AddWorkEnergyAndResidualEnergy(shearEnergy,0.);
// disispated energy per unit mass (dPhi/(rho0 V0)) (nJ/g)
mptr->AddPlastEnergy(dispEnergy);
// heat energy is Cv dT - dPhi
// The dPhi is subtracted here because it will show up in next
// time step within Cv dT (if adibatic heating occurs)
// The Cv dT was done in update pressure
IncrementHeatEnergy(mptr,res->dT,dTq0,dispEnergy);
}
// To allow some subclasses to support large deformations, the initial calculation for incremental
// deformation gradient (the dvij), volume change (delV) can be
// handled first by the subclass. This mtehod then finishes the constitutive law
void IsoPlasticity::LRPlasticityConstLaw(MPMBase *mptr,double dexx,double deyy,double dezz,double dgxy,
double dgxz,double dgyz,double delTime,int np,double delV,double eres,
PlasticProperties *p,ResidualStrains *res,Matrix3 *dR) const
{
// here dvij is total strain increment, dexxr is relative strain by subtracting off eres
double dexxr=dexx-eres;
double deyyr=deyy-eres;
double dezzr=dezz-eres;
// allow arbitrary equation of state for pressure
double dTq0 = 0.,dispEnergy = 0.;
UpdatePressure(mptr,delV,np,p,res,eres,dTq0,dispEnergy);
// Elastic deviatoric stress increment
Tensor *sp=mptr->GetStressTensor();
Tensor stk;
//Tensor st0=*sp;
double dsig[6];
double thirdDelV = delV/3.;
dsig[XX] = 2.*p->Gred*(dexxr-thirdDelV);
dsig[YY] = 2.*p->Gred*(deyyr-thirdDelV);
dsig[ZZ] = 2.*p->Gred*(dezzr-thirdDelV);
dsig[YZ] = p->Gred*dgyz;
dsig[XZ] = p->Gred*dgxz;
dsig[XY] = p->Gred*dgxy;
// incremental rotate of prior strain
Tensor *eplast=mptr->GetAltStrainTensor();
Matrix3 etn(eplast->xx,0.5*eplast->xy,0.5*eplast->xz,0.5*eplast->xy,eplast->yy,0.5*eplast->yz,
0.5*eplast->xz,0.5*eplast->yz,eplast->zz);
Matrix3 etr = etn.RMRT(*dR);
Matrix3 stn(sp->xx,sp->xy,sp->xz,sp->xy,sp->yy,sp->yz,sp->xz,sp->yz,sp->zz);
Matrix3 str = stn.RMRT(*dR);
// trial deviatoric stress
stk.xx = str(0,0) + dsig[XX];
stk.yy = str(1,1) + dsig[YY];
stk.zz = str(2,2) + dsig[ZZ];
stk.yz = str(1,2) + dsig[YZ];
stk.xz = str(0,2) + dsig[XZ];
stk.xy = str(0,1) + dsig[XY];
// Calculate plastic potential f = ||s|| - sqrt(2/3)*sy(alpha,rate,...)
HardeningAlpha alpha;
plasticLaw->UpdateTrialAlpha(mptr,np,&alpha,0); // initialize to last value
double strial = GetMagnitudeSFromDev(&stk,np);
double ftrial = strial - SQRT_TWOTHIRDS*plasticLaw->GetYield(mptr,np,delTime,&alpha,p->hardProps);
if(ftrial<0.)
{ // elastic, update stress and strain energy as usual
// set in-plane deviatoric stress
*sp = stk;
// rotate plastic strain
eplast->xx = etr(0,0);
eplast->yy = etr(1,1);
eplast->zz = etr(2,2);
eplast->xy = 2.*etr(0,1);
eplast->xz = 2.*etr(0,2);
eplast->yz = 2.*etr(1,2);
// work energy increment per unit mass (dU/(rho0 V0)) (nJ/g)
mptr->AddWorkEnergy(sp->xx*dexx + sp->yy*deyy + sp->zz*dezz
+ sp->yz*dgyz + sp->xz*dgxz + sp->xy*dgxy);
//mptr->AddWorkEnergy(0.5*((st0.xx+sp->xx)*dexx + (st0.yy+sp->yy)*deyy + (st0.zz+sp->zz)*dezz
// + (st0.yz+sp->yz)*dgyz + (st0.xz+sp->xz)*dgxz + (st0.xy+sp->xy)*dgxy));
// give material chance to update history variables that change in elastic updates
plasticLaw->ElasticUpdateFinished(mptr,np,delTime,0);
// heat energy from pressure and any pressure method items
IncrementHeatEnergy(mptr,res->dT,dTq0,dispEnergy);
return;
}
// Find direction of plastic strain and lambda for this plastic state
// Base class finds it numerically, subclass can override if solvable by more efficient meethods
Tensor dfds;
GetDfDsigma(strial,&stk,np,&dfds);
double lambdak = plasticLaw->SolveForLambdaBracketed(mptr,np,strial,&stk,p->Gred,1.,1.,delTime,&alpha,p->hardProps,0);
// Now have lambda, finish update on this particle
// Plastic strain increments on particle
double dexxp = lambdak*dfds.xx;
double deyyp = lambdak*dfds.yy;
double dezzp = lambdak*dfds.zz;
double dgxyp = 2.*lambdak*dfds.xy; // 2 for engineering plastic shear strain
double dgxzp = 2.*lambdak*dfds.xz; // 2 for engineering plastic shear strain
double dgyzp = 2.*lambdak*dfds.yz; // 2 for engineering plastic shear strain
// incremental plastic strain
eplast->xx = etr(0,0) + dexxp;
eplast->yy = etr(1,1) + deyyp;
eplast->zz = etr(2,2) + dezzp;
eplast->xy = 2.*etr(0,1) + dgxyp;
eplast->xz = 2.*etr(0,2) + dgxzp;
eplast->yz = 2.*etr(1,2) + dgyzp;
// increment particle deviatoric stresses
sp->xx = stk.xx - 2.*p->Gred*dexxp;
sp->yy = stk.yy - 2.*p->Gred*deyyp;
sp->zz = stk.zz - 2.*p->Gred*dezzp;
sp->yz = stk.yz - p->Gred*dgyzp;
sp->xz = stk.xz - p->Gred*dgxzp;
sp->xy = stk.xy - p->Gred*dgxyp;
// work energy increment per unit mass (dU/(rho0 V0)) (nJ/g)
double workEnergy = sp->xx*dexx + sp->yy*dezz + sp->zz*dezz + sp->yz*dgyz + sp->xz*dgxz + sp->xy*dgxy;
//double workEnergy = 0.5*((st0.xx+sp->xx)*dexx + (st0.yy+sp->yy)*dezz + (st0.zz+sp->zz)*dezz
// + (st0.yz+sp->yz)*dgyz + (st0.xz+sp->xz)*dgxz + (st0.xy+sp->xy)*dgxy);
// total work
mptr->AddWorkEnergy(workEnergy);
// plastic strain work
double plastEnergy = lambdak*(sp->xx*dfds.xx + sp->yy*dfds.yy + sp->zz*dfds.zz
+ 2.*sp->xy*dfds.xy + 2.*sp->xz*dfds.xz + 2.*sp->yz*dfds.yz);
// and subtrace q dalpa disispated energy per unit mass (dPhi/(rho0 V0)) (nJ/g)
double qdalphaTerm = lambdak*SQRT_TWOTHIRDS*plasticLaw->GetYieldIncrement(mptr,np,delTime,&alpha,p->hardProps);
dispEnergy += plastEnergy - qdalphaTerm;
// The cumulative dissipated energy is tracked in plastic energy
// Setting the disp energy allows heating if mechanical energy is on
mptr->AddPlastEnergy(dispEnergy);
// heat energy is Cv(dT-dTq0) - dPhi
// The dPhi is subtracted here because it will show up in next
// time step within Cv dT (if adiabatic heating occurs)
// The Cv(dT-dTq0) was done already in update pressure
IncrementHeatEnergy(mptr,res->dT,dTq0,dispEnergy);
// update internal variables
plasticLaw->UpdatePlasticInternal(mptr,np,&alpha,0);
}
// To allow some subclasses to support large deformations, the initial calculation for incremental
// deformation gradient (the dvij), volume change (delV)
// handled first by the subclass. This method then finishes the constitutive law
void IsoPlasticity::LRPlasticityConstLaw(MPMBase *mptr,double dexx,double deyy,double dgxy,
double dezz,double delTime,int np,double delV,double eres,
PlasticProperties *p,ResidualStrains *res,Matrix3 *dR) const
{
// here deij is total strain increment, dexxr is relative strain by subtracting off eres
double dexxr = dexx-eres;
double deyyr = deyy-eres;
double dezzr = dezz-eres; // In plane strain trial dezz=0, but not in axisymmetric
// allow arbitrary equation of state for pressure
double P0 = mptr->GetPressure();
double dTq0 = 0.,dispEnergy = 0.;
UpdatePressure(mptr,delV,np,p,res,eres,dTq0,dispEnergy);
double Pfinal = mptr->GetPressure();
// Deviatoric stress increment
Tensor *sp=mptr->GetStressTensor();
Tensor dels,stk;
//Tensor st0=*sp;
double thirdDelV = delV/3.;
dels.xx = 2.*p->Gred*(dexxr-thirdDelV);
dels.yy = 2.*p->Gred*(deyyr-thirdDelV);
if(np==PLANE_STRESS_MPM)
dels.zz = Pfinal-P0;
else
dels.zz = 2.*p->Gred*(dezzr-thirdDelV);
dels.xy = p->Gred*dgxy;
// incremental rotate of plastic strain
Tensor *eplast=mptr->GetAltStrainTensor();
Matrix3 etn(eplast->xx,0.5*eplast->xy,0.5*eplast->xy,eplast->yy,eplast->zz);
Matrix3 etr = etn.RMRT(*dR);
eplast->xx = etr(0,0);
eplast->yy = etr(1,1);
eplast->xy = 2.*etr(0,1);
// incremental rotation of stress
Matrix3 stn(sp->xx,sp->xy,sp->xy,sp->yy,sp->zz);
Matrix3 str = stn.RMRT(*dR);
// trial deviatoric stress
stk.xx = str(0,0) + dels.xx;
stk.yy = str(1,1) + dels.yy;
stk.zz = str(2,2) + dels.zz;
stk.xy = str(0,1) + dels.xy;
// Calculate plastic potential f = ||s|| - sqrt(2/3)*sy(alpha,rate,...)
HardeningAlpha alpha;
plasticLaw->UpdateTrialAlpha(mptr,np,&alpha,0); // initialize to last value and zero plastic strain rate
double strial = GetMagnitudeSFromDev(&stk,np);
double ftrial = strial - SQRT_TWOTHIRDS*plasticLaw->GetYield(mptr,np,delTime,&alpha,p->hardProps);
if(ftrial<0.)
{ // elastic, update stress and strain energy as usual
// set in plane deviatoric stress
sp->xx = stk.xx;
sp->xy = stk.xy;
sp->yy = stk.yy;
sp->zz = stk.zz;
// work energy increment per unit mass (dU/(rho0 V0)) (by midpoint rule) (nJ/g)
// energy units are also Pa mm^3/g, i.e., same as stress units
if(np==AXISYMMETRIC_MPM)
{ mptr->AddWorkEnergy(sp->xx*dexx + sp->yy*deyy + sp->xy*dgxy + sp->zz*dezz);
//mptr->AddWorkEnergy(0.5*((st0.xx+sp->xx)*dexx + (st0.yy+sp->yy)*deyy + (st0.xy+sp->xy)*dgxy + (st0.zz+sp->zz)*dezz));
}
else if(np==PLANE_STRESS_MPM)
{ // zz deformation
mptr->IncrementDeformationGradientZZ(-p->psLr2G*(dexxr+deyyr) + eres);
mptr->AddWorkEnergy(sp->xx*dexx + sp->yy*deyy + sp->xy*dgxy);
//mptr->AddWorkEnergy(0.5*((st0.xx+sp->xx)*dexx + (st0.yy+sp->yy)*deyy + (st0.xy+sp->xy)*dgxy));
}
else
{ mptr->AddWorkEnergy(sp->xx*dexx + sp->yy*deyy + sp->xy*dgxy);
//mptr->AddWorkEnergy(0.5*((st0.xx+sp->xx)*dexx + (st0.yy+sp->yy)*deyy + (st0.xy+sp->xy)*dgxy));
}
// give subclass material chance to update history variables that change in elastic updates
plasticLaw->ElasticUpdateFinished(mptr,np,delTime,0);
// heat energy from pressure and any pressure method items
IncrementHeatEnergy(mptr,res->dT,dTq0,dispEnergy);
return;
}
// Find lambda for this plastic state
// Base class finds it numerically, subclass can override if solvable by more efficient methods
double lambdak = plasticLaw->SolveForLambdaBracketed(mptr,np,strial,&stk,p->Gred,p->psKred,Pfinal,delTime,&alpha,p->hardProps,0);
// Now have lambda, finish update on this particle
Tensor dfds;
if(np==PLANE_STRESS_MPM)
{ // get final stress state
double d1 = (1 + p->psKred*lambdak);
double d2 = (1.+2.*p->Gred*lambdak);
double n1 = (stk.xx+stk.yy-2.*Pfinal)/d1;
double n2 = (-stk.xx+stk.yy)/d2;
double sxx = (n1-n2)/2.;
double syy = (n1+n2)/2.;
double txy = stk.xy/d2;
// find increment in deviatoric stress
dels.xx = sxx+Pfinal-sp->xx;
dels.yy = syy+Pfinal-sp->yy;
dels.xy = txy-sp->xy;
// get final direction
dfds.xx = (2.*sxx-syy)/3.;
dfds.yy = (2.*syy-sxx)/3.;
dfds.zz = -(dfds.xx+dfds.yy);
dfds.xy = txy; // tensorial shear strain
// zz deformation
mptr->IncrementDeformationGradientZZ(-p->psLr2G*(dexxr+deyyr - lambdak*(dfds.xx+dfds.yy)) + eres + lambdak*dfds.zz);
// If fully plastic, the increment in deviatoric stress should be zero
// sxx = sigmaxx+Pfinal = st0.xx, syy = sigmayy+Pfinal = st0.yy, szz = Pfinal
// But first two must be wrong because trace is no longer zero?
//
// This is probably wrong
// i.e.: n1 + 2*Pfinal = st0.xx+st0.yy
// (stk.xx+stk.yy)/d1 - 2*Pfinal*(1/d1-1) = st0.xx+st0.yy
// But (stk.xx+stk.yy) = (st0.xx+st0.yy) + 2.*Gred*(dexxr+deyyr-2*thirdDelV)
// (st0.xx+st0.yy)(1/d1-1) - 2*Pfinal*(1/d1-1) = -2.*Gred*(dexxr+deyyr-2*thirdDelV)/d1
// (st0.xx+st0.yy-2*Pfinal)*(1-d1) = -2.*Gred*(dexxr+deyyr-2*thirdDelV)
// B*Kred*lam = 2.*Gred*A or lam = 2.*Gred*A/(B*Kred)
// where B = st0.xx+st0.yy-2*Pfinal, and A = (dexxr+deyyr-2*thirdDelV)
// Then d1 = 1+2*Gred*A/B, n1 = ((st0.xx+st0.yy) + 2*Gred*A - 2*Pfinal)/d1 = (B+2*Gred*A)*B/(B+2*Gred*A) = B
//
// Also expect syy-sxx = sigmayy-sigmaxx = st0.yy-st0.xx = n2
// (stk.yy-stk.xx)/d2 = st0.yy-st0.xx
// (st0.yy-st0.xx)/d2 + 2*Gred*(deyyr-dexxr)/d2 = (st0.yy-st0.xx)
// (st0.yy-st0.xx)(d2-1) = - 2*Gred*(deyyr-dexxr)
// lam = (deyyr-dexxr)/(st0.yy-st0.xx)
// Then n2 = (st0.yy-st0.xx + 2*Gred*(deyyr-dexxr))/(1+2*Gred*(deyyr-dexxr)/(st0.yy-st0.xx)) = st0.yy-st0.xx
//
// But these two lam's seem to differ?
// We can write
}
else
{ // get final direction
GetDfDsigma(strial,&stk,np,&dfds);
}
// Plastic strain increments on particle
double dexxp = lambdak*dfds.xx;
double deyyp = lambdak*dfds.yy;
double dezzp = lambdak*dfds.zz;
double dgxyp = 2.*lambdak*dfds.xy; // 2 for engineering plastic shear strain
eplast->xx += dexxp;
eplast->yy += deyyp;
eplast->zz += dezzp;
eplast->xy += dgxyp;
// increment particle deviatoric stresses (plane stress increments found above)
if(np!=PLANE_STRESS_MPM)
{ dels.xx -= 2.*p->Gred*dexxp;
dels.yy -= 2.*p->Gred*deyyp;
dels.xy -= p->Gred*dgxyp;
dels.zz -= 2.*p->Gred*dezzp;
sp->zz += dels.zz;
}
else
sp->zz = Pfinal; // now equal to Pfinal
// update in-plane stressees
sp->xx = str(0,0) + dels.xx;
sp->yy = str(1,1) + dels.yy;
sp->xy = str(0,1) + dels.xy;
// Elastic work increment per unit mass (dU/(rho0 V0)) (nJ/g)
double workEnergy = sp->xx*dexx + sp->yy*deyy + sp->xy*dgxy;
//double workEnergy = 0.5*((st0.xx+sp->xx)*dexx + (st0.yy+sp->yy)*deyy + (st0.xy+sp->xy)*dgxy);
if(np==AXISYMMETRIC_MPM)
{ workEnergy += sp->zz*dezz;
//workEnergy += 0.5*(st0.zz+sp->zz)*dezz;
}
// total work
mptr->AddWorkEnergy(workEnergy);
// plastic strain work
double plastEnergy = lambdak*(sp->xx*dfds.xx + sp->yy*dfds.yy + sp->zz*dfds.zz + 2.*sp->xy*dfds.xy);
// dand subtract q dalpha to get isispated energy per unit mass (dPhi/(rho0 V0)) (nJ/g)
double qdalphaTerm = lambdak*SQRT_TWOTHIRDS*plasticLaw->GetYieldIncrement(mptr,np,delTime,&alpha,p->hardProps);
dispEnergy += plastEnergy - qdalphaTerm;
// The cumulative dissipated energy is tracked in plastic energy
mptr->AddPlastEnergy(dispEnergy);
// heat energy is Cv(dT-dTq0) - dPhi
// The dPhi is subtracted here because it will show up in next
// time step within Cv dT (if adibatic heating occurs)
IncrementHeatEnergy(mptr,res->dT,dTq0,dispEnergy);
// update internal variables
plasticLaw->UpdatePlasticInternal(mptr,np,&alpha,0);
}
/* Take increments in strain and calculate new Particle: strains, rotation strain,
stresses, strain energy,
dvij are (gradient rates X time increment) to give deformation gradient change
For Axisymmetry: x->R, y->Z, z->theta, np==AXISYMMEtRIC_MPM, otherwise dvzz=0
This material tracks pressure and stores deviatoric stress only in particle stress
tensor
*/
void HEIsotropic::MPMConstitutiveLaw(MPMBase *mptr,Matrix3 du,double delTime,int np,void *properties,
ResidualStrains *res,int historyOffset) const
{
HEPlasticProperties *p = (HEPlasticProperties *)properties;
// store initial stress
Tensor *sp = mptr->GetStressTensor();
Tensor st0 = *sp;
// Compute Elastic Predictor
// ============================================
// Update total deformation gradient, and calculate trial B
Tensor Btrial;
double detdF = IncrementDeformation(mptr,du,&Btrial,np);
// Deformation gradients and Cauchy tensor differ in plane stress and plane strain
// This code handles plane strain, axisymmetric, and 3D - Plane stress is blocked
double J = detdF * mptr->GetHistoryDble(J_History,historyOffset);
mptr->SetHistoryDble(J_History,J,historyOffset); // Stocking J
// J is determinant of F (or sqrt root of determinant of B), Jeff is normalized to residual stretch
double dJres = GetIncrementalResJ(mptr,res);
double Jres = dJres * mptr->GetHistoryDble(J_History+1,historyOffset);
mptr->SetHistoryDble(J_History+1,Jres,historyOffset);
double Jeff = J/Jres;
// Get hydrostatic stress component in subroutine
double dTq0 = 0.,dispEnergy = 0.;
UpdatePressure(mptr,J,detdF,np,Jeff,delTime,p,res,dJres,historyOffset,dTq0,dispEnergy);
// Others constants
double J23 = pow(J, 2./3.)/Jres;
// find Trial (Cauchy stress)/rho0
// (Trial_s/rho0 = Trial_s*rho/(rho*rho0) = (Trial_tau*rho/rho0^2) = (1/J)*(Trial_tau/rho0)
Tensor stk = GetTrialDevStressTensor(&Btrial,J*J23,np,p->Gred);
// Checking for plastic loading
// ============================================
// Get magnitude of the deviatoric stress tensor
// ||s|| = sqrt(s.s)
// Set alpint for particle
HardeningAlpha alpha;
plasticLaw->UpdateTrialAlpha(mptr,np,&alpha,historyOffset);
// Trial stress state
double magnitude_strial = GetMagnitudeS(&stk,np);
double gyld = plasticLaw->GetYield(mptr,np,delTime,&alpha,p->hardProps);
double ftrial = magnitude_strial-SQRT_TWOTHIRDS*gyld;
//cout << " #magnitude_strial = "<< magnitude_strial<< " GetYield = "<< gyld<< " ftrial = "<< ftrial<< endl;
//cout << " #yldred = "<< yldred << " Epred = "<< Epred << " gyld = "<< gyld <<" alpint = "<< alpint<< " ftrial = "<< ftrial<< endl;
// these will be needed for elastic or plastic
Tensor *pB = mptr->GetAltStrainTensor();
//============================
// TEST
//============================
if(ftrial<=0.)
{ // if elastic
//============================
// save on particle
*pB = Btrial;
// Get specifique stress i.e. (Cauchy Stress)/rho = J*(Cauchy Stress)/rho0 = (Kirchoff Stress)/rho0
// The deviatoric stress was calculated as (Cauchy Stress)/rho, so need to scale by J to get correct stress
sp->xx = J*stk.xx;
sp->yy = J*stk.yy;
sp->xy = J*stk.xy;
sp->zz = J*stk.zz;
// work energy per unit mass (U/(rho0 V0)) and we are using
// W(F) as the energy density per reference volume V0 (U/V0) and not current volume V
double workEnergy = 0.5*((st0.xx+sp->xx)*du(0,0)
+ (st0.yy+sp->yy)*du(1,1)
+ (st0.zz+sp->zz)*du(2,2)
+ (st0.xy+sp->xy)*(du(1,0)+du(0,1)));
if(np==THREED_MPM)
{ sp->xz = J*stk.xz;
sp->yz = J*stk.yz;
workEnergy += 0.5*((st0.yz+sp->yz)*(du(2,1)+du(1,2))
+ (st0.xz+sp->xz)*(du(2,0)+du(0,2)));
}
mptr->AddWorkEnergy(workEnergy);
// residual energy or sigma.deres - it is zero here for isotropic material
// because deviatoric stress is traceless and deres has zero shear terms
// residual energy due to pressure was added in the pressure update
// heat energy is Cv(dT-dTq0) - dPhi, all from pressure update
IncrementHeatEnergy(mptr,res->dT,dTq0,dispEnergy);
// give material chance to update history variables that change in elastic updates
plasticLaw->ElasticUpdateFinished(mptr,np,delTime,historyOffset);
return;
}
// Plastic behavior - Return Mapping algorithm
//=====================================================
// if plastic
// JAN: Use hardening law method (which can now use other laws too)
double Ie1bar = (Btrial.xx+Btrial.yy+Btrial.zz)/(3.*J23);
double MUbar = Jres*p->Gred*Ie1bar;
// Find lambda for this plastic state
double dlambda = plasticLaw->SolveForLambdaBracketed(mptr,np,magnitude_strial,&stk,
MUbar,1.,1.,delTime,&alpha,p->hardProps,historyOffset);
// update deviatoric stress (need to scale by J to get to Kirchoff stress/rho
Tensor nk = GetNormalTensor(&stk,magnitude_strial,np);
//cout << "nk.xx = " << nk.xx << "nk.xy = " << nk.xy << endl;
double twoMuLam = 2.*MUbar*dlambda;
sp->xx = J*(stk.xx - twoMuLam*nk.xx);
sp->yy = J*(stk.yy - twoMuLam*nk.yy);
sp->zz = J*(stk.zz - twoMuLam*nk.zz);
sp->xy = J*(stk.xy - twoMuLam*nk.xy);
if(np == THREED_MPM)
{ sp->xz = J*(stk.xz - twoMuLam*nk.xz);
sp->yz = J*(stk.yz - twoMuLam*nk.yz);
}
// save on particle
double twoThirdsLamI1bar = 2.*dlambda*Ie1bar;
pB->xx = Btrial.xx - twoThirdsLamI1bar*nk.xx;
pB->yy = Btrial.yy - twoThirdsLamI1bar*nk.yy;
pB->zz = Btrial.zz - twoThirdsLamI1bar*nk.zz;
pB->xy = Btrial.xy - twoThirdsLamI1bar*nk.xy;
if(np == THREED_MPM)
{ pB->xz = Btrial.xz - twoThirdsLamI1bar*nk.xz;
pB->yz = Btrial.yz - twoThirdsLamI1bar*nk.yz;
}
/* Old method collecting B from stresses
pB->xx = (sp->xx/p->Gred+Ie1bar)*J23;
pB->yy = (sp->yy/p->Gred+Ie1bar)*J23;
pB->zz = (sp->zz/p->Gred+Ie1bar)*J23;
pB->xy = sp->xy*J23/p->Gred;
if(np == THREED_MPM)
{ pB->xz = sp->xz*J23/p->Gred;
pB->yz = sp->yz*J23/p->Gred;
}
*/
// strain energy per unit mass (U/(rho0 V0)) and we are using
double workEnergy = 0.5*((st0.xx+sp->xx)*du(0,0)
+ (st0.yy+sp->yy)*du(1,1)
+ (st0.zz+sp->zz)*du(2,2)
+ (st0.xy+sp->xy)*(du(1,0)+du(0,1)));
if(np==THREED_MPM)
{ workEnergy += 0.5*((st0.yz+sp->yz)*(du(2,1)+du(1,2))
+ (st0.xz+sp->xz)*(du(2,0)+du(0,2)));
}
// total work
mptr->AddWorkEnergy(workEnergy);
// residual energy or sigma.deres - it is zero here for isotropic material
// because deviatoric stress is traceless and deres has zero shear terms
// residual energy due to pressure was added in the pressure update
// Plastic work increment per unit mass (dw/(rho0 V0)) (nJ/g)
dispEnergy += dlambda*(sp->xx*nk.xx + sp->yy*nk.yy + sp->zz*nk.zz + 2.*sp->xy*nk.xy);
if(np==THREED_MPM) dispEnergy += 2.*dlambda*(sp->xz*nk.xz + sp->yz*nk.yz);
// Subtract q.dalpha to get final disispated energy per unit mass (dPhi/(rho0 V0)) (nJ/g)
dispEnergy -= dlambda*SQRT_TWOTHIRDS*plasticLaw->GetYieldIncrement(mptr,np,delTime,&alpha,p->hardProps);
// The cumulative dissipated energy is tracked in plastic energy
mptr->AddPlastEnergy(dispEnergy);
// heat energy is Cv(dT-dTq0) - dPhi
IncrementHeatEnergy(mptr,res->dT,dTq0,dispEnergy);
// update internal variables in the plastic law
plasticLaw->UpdatePlasticInternal(mptr,np,&alpha,historyOffset);
}
/* For 2D MPM analysis, take increments in strain and calculate new
Particle: strains, rotation strain, stresses, strain energy, angle
dvij are (gradient rates X time increment) to give deformation gradient change
Assumes linear elastic, uses hypoelastic correction
For Axisymmetric MPM, x->R, y->Z, x->theta, and dvzz is change in hoop strain
(i.e., du/r on particle and dvzz will be zero if not axisymmetric)
*/
void Elastic::MPMConstLaw(MPMBase *mptr,double dvxx,double dvyy,double dvxy,double dvyx,double dvzz,
double delTime,int np,void *properties,ResidualStrains *res) const
{
// cast pointer to material-specific data
ElasticProperties *p = (ElasticProperties *)properties;
// Add to total strain
Tensor *ep=mptr->GetStrainTensor();
ep->xx+=dvxx;
ep->yy+=dvyy;
double dgam=dvxy+dvyx;
ep->xy+=dgam;
double dwrotxy=dvyx-dvxy;
// residual strains (thermal and moisture)
double erxx = p->alpha[1]*res->dT;
double eryy = p->alpha[2]*res->dT;
double erxy = p->alpha[3]*res->dT;
double erzz = CTE3*res->dT;
if(DiffusionTask::active)
{ erxx += p->beta[1]*res->dC;
eryy += p->beta[2]*res->dC;
erxy += p->beta[3]*res->dC;
erzz += CME3*res->dC;
}
// moisture and thermal strain and temperature change
// (when diffusion, conduction, OR thermal ramp active)
double dvxxeff = dvxx - erxx;
double dvyyeff = dvyy - eryy;
double dgameff = dgam - erxy;
// save initial stresses
Tensor *sp=mptr->GetStressTensor();
Tensor st0=*sp;
// find stress (Units N/m^2 cm^3/g)
// this does xx, yy, ans xy only. zz do later if needed
double c1,c2,c3;
if(np==AXISYMMETRIC_MPM)
{ // axisymmetric strain
ep->zz += dvzz;
// hoop stress affect on RR, ZZ, and RZ stresses
double dvzzeff = dvzz - erzz;
c1=p->C[1][1]*dvxxeff + p->C[1][2]*dvyyeff + p->C[4][1]*dvzzeff + p->C[1][3]*dgameff;
c2=p->C[1][2]*dvxxeff + p->C[2][2]*dvyyeff + p->C[4][2]*dvzzeff + p->C[2][3]*dgameff;
c3=p->C[1][3]*dvxxeff + p->C[2][3]*dvyyeff + p->C[4][3]*dvzzeff + p->C[3][3]*dgameff;
}
else
{ c1=p->C[1][1]*dvxxeff + p->C[1][2]*dvyyeff + p->C[1][3]*dgameff;
c2=p->C[1][2]*dvxxeff + p->C[2][2]*dvyyeff + p->C[2][3]*dgameff;
c3=p->C[1][3]*dvxxeff + p->C[2][3]*dvyyeff + p->C[3][3]*dgameff;
}
Hypo2DCalculations(mptr,-dwrotxy,c1,c2,c3);
// work and resdiaul strain energu increments
double workEnergy = 0.5*((st0.xx+sp->xx)*dvxx + (st0.yy+sp->yy)*dvyy + (st0.xy+sp->xy)*dgam);
double resEnergy = 0.5*((st0.xx+sp->xx)*erxx + (st0.yy+sp->yy)*eryy + (st0.xy+sp->xy)*erxy);
if(np==PLANE_STRAIN_MPM)
{ // need to add back terms to get from reduced cte to actual cte
sp->zz += p->C[4][1]*(dvxx+p->alpha[5]*erzz)+p->C[4][2]*(dvyy+p->alpha[6]*erzz)
+p->C[4][3]*(dgam+p->alpha[7]*erzz)-p->C[4][4]*erzz;
// extra residual energy increment per unit mass (dU/(rho0 V0)) (by midpoint rule) (uJ/g)
resEnergy += 0.5*(st0.zz+sp->zz)*erzz;
}
else if(np==PLANE_STRESS_MPM)
{ ep->zz += p->C[4][1]*dvxxeff+p->C[4][2]*dvyyeff+p->C[4][3]*dgameff+erzz;
}
else
{ // axisymmetric hoop stress
sp->zz += p->C[4][1]*dvxxeff + p->C[4][2]*dvyyeff + p->C[4][4]*(dvzz - erzz) + p->C[4][3]*dgameff;
// extra work and residual energy increment per unit mass (dU/(rho0 V0)) (by midpoint rule) (uJ/g)
workEnergy += 0.5*(st0.zz+sp->zz)*dvzz;
resEnergy += 0.5*(st0.zz+sp->zz)*erzz;
}
mptr->AddWorkEnergyAndResidualEnergy(workEnergy, resEnergy);
// track heat energy
IncrementHeatEnergy(mptr,res->dT,0.,0.);
}
/* Take increments in strain and calculate new Particle: strains, rotation strain,
stresses, strain energy,
dvij are (gradient rates X time increment) to give deformation gradient change
For Axisymmetry: x->R, y->Z, z->theta, np==AXISYMMEtRIC_MPM, otherwise dvzz=0
This material tracks pressure and stores deviatoric stress only in particle stress tensor
*/
void ClampedNeohookean::MPMConstitutiveLaw(MPMBase *mptr,Matrix3 du,double delTime,int np,void *properties,
ResidualStrains *res,int historyOffset) const
{
// Update total deformation gradient, and calculate trial B
Tensor Btrial;
double detDF = IncrementDeformation(mptr,du,&Btrial,np);
// global J
double J = detDF * mptr->GetHistoryDble(J_History,historyOffset);
mptr->SetHistoryDble(J_History,J,historyOffset);
// convert Btrial to matrix to get eigenvalues and check for clamping
Matrix3 Belas(Btrial.xx,Btrial.xy,Btrial.xz,
Btrial.xy,Btrial.yy,Btrial.yz,
Btrial.xz,Btrial.yz,Btrial.zz);
if(np!=THREED_MPM) Belas.setIs2D(true);
// get Eigenvalues and Eigenvectors
Vector lam2 = Belas.Eigenvalues();
// clamp eigenvalues if needed
bool clamped = false;
if(lam2.x<lamMin2 || lam2.x>lamMax2 || lam2.y<lamMin2 || lam2.y>lamMax2 || lam2.z<lamMin2 || lam2.z>lamMax2)
clamped = true;
// Get Je and Jp, adjusting if clamped
double Je,Jp;
Matrix3 Ucol;
if(clamped)
{ // Find Belas = U.LAM.UT
Ucol = Belas.Eigenvectors(lam2);
// clamp values now
if(lam2.x<lamMin2)
lam2.x = lamMin2;
else if(lam2.x>lamMax2)
lam2.x = lamMax2;
if(lam2.y<lamMin2)
lam2.y = lamMin2;
else if(lam2.y>lamMax2)
lam2.y = lamMax2;
if(lam2.z<lamMin2)
lam2.z = lamMin2;
else if(lam2.z>lamMax2)
lam2.z = lamMax2;
Matrix3 UcolT = Ucol.Transpose();
Matrix3 Lam(lam2.x,0.,0.,lam2.y,lam2.z);
Matrix3 LamUcolT = Lam*UcolT;
Belas = Ucol*LamUcolT;
// get Je and Jp
Je = sqrt(lam2.x*lam2.y*lam2.z);
Jp = J/Je;
mptr->SetHistoryDble(JP_HISTORY,Jp,historyOffset);
}
else
{ Jp = mptr->GetHistoryDble(JP_HISTORY,historyOffset);
Je = J/Jp;
if(elasticModel==ELASTIC_DISNEY)
Ucol = Belas.Eigenvectors(lam2);
}
// store B elastic
Tensor *sp=mptr->GetStressTensor();
Tensor *B = mptr->GetAltStrainTensor();
B->xx = Belas(0,0);
B->yy = Belas(1,1);
B->zz = Belas(2,2);
B->xy = Belas(0,1);
if(np==THREED_MPM)
{ B->xz = Belas(0,2);
B->yz = Belas(1,2);
}
// change mechanical properties by hardening
double arg = exp(hardening*(1.-Jp));
double altGsp = pr.Gsp*arg;
double altLamesp = pr.Lamesp*arg;
// account for residual stresses
double dJres = GetIncrementalResJ(mptr,res);
double Jres = dJres*mptr->GetHistoryDble(J_History+1,historyOffset);
mptr->SetHistoryDble(J_History+1,Jres,historyOffset);
double resStretch = pow(Jres,1./3.);
double Jres23 = resStretch*resStretch;
// account for residual stresses relative to elastic J
double Jeff = Je/Jres;
// for incremental energy, store initial stress and pressure
Tensor *sporig=mptr->GetStressTensor();
Tensor st0 = *sporig;
double Pfinal,p0=mptr->GetPressure();
if(elasticModel==ELASTIC_DISNEY)
{ // Use model from Disney paper
// Get Cauchy stress/rho0
double sig[3][3];
double lam[3];
lam[0]=sqrt(lam2.x)/resStretch;
lam[1]=sqrt(lam2.y)/resStretch;
lam[2]=sqrt(lam2.z)/resStretch;
for(int i=0;i<3;i++)
{ for(int j=i;j<3;j++)
{ sig[i][j] = 0.;
for(int k=0;k<3;k++)
{ sig[i][j] += (2.*altGsp*lam[k]*(lam[k]-1)/Jeff + altLamesp*(Jeff-1))*Ucol(i,k)*Ucol(j,k);
}
}
}
// update pressure (*J to get Kirchoff pressure)
Pfinal = -J*(sig[0][0]+sig[1][1]+sig[2][2])/3.;
mptr->SetPressure(Pfinal);
// get and set deviatoric stress
// find eviatoric (Kirchoff stress)/rho0 = deviatoric (Cauchy stress)J/rho0
sp->xx = J*sig[0][0]+Pfinal;
sp->yy = J*sig[1][1]+Pfinal;
sp->zz = J*sig[2][2]+Pfinal;
sp->xy = J*sig[0][1];
if(np==THREED_MPM)
{ sp->xz = J*sig[0][2];
sp->yz = J*sig[1][2];
}
}
else
{ // Use standard neo-Hookean law
// update pressure (*J to get Kirchoff pressure)
Pfinal = -J*(GetVolumetricTerms(Jeff,altLamesp) + (altGsp/Jeff)*((B->xx+B->yy+B->zz)/(3.*Jres23) - 1.));
mptr->SetPressure(Pfinal);
// Account for density change in specific stress
// i.e.. Get (Kirchoff Stress)/rho0
double GJeff = J*resStretch*altGsp/Je; // = J*(Jres^(1/3) G/Je) to get Kirchoff
// find deviatoric (Kirchoff stress)/rho0 = deviatoric (Cauchy stress)J/rho0
double I1third = (B->xx+B->yy+B->zz)/3.;
sp->xx = GJeff*(B->xx-I1third);
sp->yy = GJeff*(B->yy-I1third);
sp->zz = GJeff*(B->zz-I1third);
sp->xy = GJeff*B->xy;
if(np==THREED_MPM)
{ sp->xz = GJeff*B->xz;
sp->yz = GJeff*B->yz;
}
}
// work and residual energies
double delV = 1. - 1./detDF; // total volume change
double avgP = 0.5*(p0+Pfinal);
double dilEnergy = -avgP*delV;
// incremental residual energy
double delVres = 1. - 1./dJres;
double resEnergy = -avgP*delVres;
// incremental work energy = shear energy
double shearEnergy = 0.5*((sp->xx+st0.xx)*du(0,0) + (sp->yy+st0.yy)*du(1,1) + (sp->zz+st0.zz)*du(2,2)+
(sp->xy+st0.xy)*(du(0,1)+du(1,0)));
if(np==THREED_MPM)
{ shearEnergy += 0.5*((sp->xz+st0.xz)*(du(0,2)+du(2,0)) + (sp->yz+st0.yz)*(du(1,2)+du(2,1)));
}
// strain energy
double dU = dilEnergy + shearEnergy;
mptr->AddWorkEnergyAndResidualEnergy(dU,resEnergy);
// thermodynamics heat and temperature
// Should find energy dissipated by plasticity and add in third term
IncrementHeatEnergy(mptr,res->dT,0.,0.);
}
// Once stress deformation has been decomposed, finish calculations in the material axis system
// When stress are found, they are rotated back to the global axes (using Rtot and dR)
// Similar, strain increments are rotated back to find work energy (done in global system)
void Elastic::LRElasticConstitutiveLaw(MPMBase *mptr,Matrix3 de,Matrix3 er,Matrix3 Rtot,Matrix3 dR,
Matrix3 *Rnmatot,int np,void *properties,ResidualStrains *res) const
{
// effective strains
double dvxxeff = de(0,0)-er(0,0);
double dvyyeff = de(1,1)-er(1,1);
double dvzzeff = de(2,2)-er(2,2);
double dgamxy = 2.*de(0,1);
// save initial stresses
Tensor *sp=mptr->GetStressTensor();
//Tensor st0=*sp;
// stress increments
// cast pointer to material-specific data
ElasticProperties *p = GetElasticPropertiesPointer(properties);
if(np==THREED_MPM)
{ double dgamyz = 2.*de(1,2);
double dgamxz = 2.*de(0,2);
// update sigma = dR signm1 dRT + Rtot dsigma RtotT
double dsigyz = p->C[3][3]*dgamyz;
double dsigxz = p->C[4][4]*dgamxz;
double dsigxy = p->C[5][5]*dgamxy;
Matrix3 dsig(p->C[0][0]*dvxxeff + p->C[0][1]*dvyyeff + p->C[0][2]*dvzzeff, dsigxy, dsigxz,
dsigxy, p->C[1][0]*dvxxeff + p->C[1][1]*dvyyeff + p->C[1][2]*dvzzeff, dsigyz,
dsigxz, dsigyz, p->C[2][0]*dvxxeff + p->C[2][1]*dvyyeff + p->C[2][2]*dvzzeff);
Matrix3 dsigrot = dsig.RMRT(Rtot);
Matrix3 stn(sp->xx,sp->xy,sp->xz,sp->xy,sp->yy,sp->yz,sp->xz,sp->yz,sp->zz);
Matrix3 str = stn.RMRT(dR);
sp->xx = str(0,0) + dsigrot(0,0);
sp->yy = str(1,1) + dsigrot(1,1);
sp->zz = str(2,2) + dsigrot(2,2);
sp->xy = str(0,1) + dsigrot(0,1);
sp->xz = str(0,2) + dsigrot(0,2);
sp->yz = str(1,2) + dsigrot(1,2);
// stresses are in global coordinates so need to rotate strain and residual
// strain to get work energy increment per unit mass (dU/(rho0 V0))
Matrix3 derot = de.RMRT(Rtot);
Matrix3 errot = er.RMRT(Rtot);
mptr->AddWorkEnergyAndResidualEnergy(sp->xx*derot(0,0) + sp->yy*derot(1,1) + sp->zz*derot(2,2)
+ 2.*(sp->yz*derot(1,2) + sp->xz*derot(0,2) + sp->xy*derot(0,1)),
sp->xx*errot(0,0) + sp->yy*errot(1,1) + sp->zz*errot(2,2)
+ 2.*(sp->yz*errot(1,2) + sp->xz*errot(0,2) + sp->xy*errot(0,1)) );
//mptr->AddWorkEnergyAndResidualEnergy(0.5*((st0.xx+sp->xx)*derot(0,0) + (st0.yy+sp->yy)*derot(1,1)
// + (st0.zz+sp->zz)*derot(2,2)) + (st0.yz+sp->yz)*derot(1,2)
// + (st0.xz+sp->xz)*derot(0,2) + (st0.xy+sp->xy)*derot(0,1),
// 0.5*((st0.xx+sp->xx)*errot(0,0) + (st0.yy+sp->yy)*errot(1,1)
// + (st0.zz+sp->zz)*errot(2,2)) + (st0.yz+sp->yz)*errot(1,2)
// + (st0.xz+sp->xz)*errot(0,2) + (st0.xy+sp->xy)*errot(0,1));
}
else
{ // find stress increment
// this does xx, yy, and xy only. zz done later if needed
double dsxx,dsyy;
if(np==AXISYMMETRIC_MPM)
{ dsxx = p->C[1][1]*dvxxeff + p->C[1][2]*dvyyeff + p->C[4][1]*dvzzeff ;
dsyy = p->C[1][2]*dvxxeff + p->C[2][2]*dvyyeff + p->C[4][2]*dvzzeff;
}
else
{ dsxx = p->C[1][1]*dvxxeff + p->C[1][2]*dvyyeff;
dsyy = p->C[1][2]*dvxxeff + p->C[2][2]*dvyyeff;
}
double dsxy = p->C[3][3]*dgamxy;
// update sigma = dR signm1 dRT + Rtot dsigma RtotT
Matrix3 dsig(dsxx,dsxy,dsxy,dsyy,0.);
Matrix3 dsigrot = dsig.RMRT(Rtot);
Matrix3 stn(sp->xx,sp->xy,sp->xy,sp->yy,sp->zz);
Matrix3 str = stn.RMRT(dR);
sp->xx = str(0,0) + dsigrot(0,0);
sp->yy = str(1,1) + dsigrot(1,1);
sp->xy = str(0,1) + dsigrot(0,1);
// stresses are in global coordinate so need to rotate strain and residual
// strain to get work energy increment per unit mass (dU/(rho0 V0))
double ezzr = er(2,2);
Matrix3 derot = de.RMRT(Rtot);
Matrix3 errot = er.RMRT(Rtot);
// work and residual strain energy increments and sigma or F in z direction
double workEnergy = sp->xx*derot(0,0) + sp->yy*derot(1,1) + 2.0*sp->xy*derot(0,1);
double resEnergy = sp->xx*errot(0,0) + sp->yy*errot(1,1) + 2.*sp->xy*errot(0,1);
//double workEnergy = 0.5*((st0.xx+sp->xx)*derot(0,0) + (st0.yy+sp->yy)*derot(1,1)) + (st0.xy+sp->xy)*derot(0,1);
//double resEnergy = 0.5*((st0.xx+sp->xx)*errot(0,0) + (st0.yy+sp->yy)*errot(1,1)) + (st0.xy+sp->xy)*errot(0,1);
if(np==PLANE_STRAIN_MPM)
{ // need to add back terms to get from reduced cte to actual cte
sp->zz += p->C[4][1]*(dvxxeff+p->alpha[5]*ezzr) + p->C[4][2]*(dvyyeff+p->alpha[6]*ezzr) - p->C[4][4]*ezzr;
// extra residual energy increment per unit mass (dU/(rho0 V0)) (by midpoint rule) (nJ/g)
resEnergy += sp->zz*ezzr;
//resEnergy += 0.5*(st0.zz+sp->zz)*ezzr;
}
else if(np==PLANE_STRESS_MPM)
{ // zz deformation
mptr->IncrementDeformationGradientZZ(p->C[4][1]*dvxxeff + p->C[4][2]*dvyyeff + ezzr);
}
else
{ // axisymmetric hoop stress
sp->zz += p->C[4][1]*dvxxeff + p->C[4][2]*dvyyeff + p->C[4][4]*dvzzeff;
// extra work and residual energy increment per unit mass (dU/(rho0 V0)) (by midpoint rule) (nJ/g)
workEnergy += sp->zz*de(2,2);
resEnergy += sp->zz*ezzr;
//workEnergy += 0.5*(st0.zz+sp->zz)*de(2,2);
//resEnergy += 0.5*(st0.zz+sp->zz)*ezzr;
}
mptr->AddWorkEnergyAndResidualEnergy(workEnergy, resEnergy);
}
// track heat energy
IncrementHeatEnergy(mptr,res->dT,0.,0.);
}
