void
M1Material :: giveRealStressVector_3d(FloatArray &answer,
GaussPoint *gp,
const FloatArray &totalStrain,
TimeStep *tStep)
{
answer.resize(6);
answer.zero();
// get the status at the beginning
M1MaterialStatus *status = static_cast< M1MaterialStatus * >( this->giveStatus(gp) );
// prepare status at the end
this->initTempStatus(gp);
// get the initial values of plastic strains on microplanes (set to zero in the first step)
FloatArray epspN = status->giveNormalMplanePlasticStrains();
if ( epspN.giveSize() < numberOfMicroplanes ) {
epspN.resize(numberOfMicroplanes);
epspN.zero();
}
// loop over microplanes
FloatArray sigN(numberOfMicroplanes);
IntArray plState(numberOfMicroplanes);
for ( int imp = 1; imp <= numberOfMicroplanes; imp++ ) {
Microplane *mPlane = this->giveMicroplane(imp - 1, gp);
//IntegrationPointStatus *mPlaneStatus = this->giveMicroplaneStatus(mPlane);
double epsN = computeNormalStrainComponent(mPlane, totalStrain);
// evaluate trial stress on the microplane
double sigTrial = EN * ( epsN - epspN.at(imp) );
// evaluate the yield stress (from total microplane strain, not from its plastic part)
double sigYield = EN * ( s0 + HN * epsN ) / ( EN + HN );
if ( sigYield < 0. ) {
sigYield = 0.;
}
// check whether the yield stress is exceeded and set the microplane stress
if ( sigTrial > sigYield ) { //plastic yielding
sigN.at(imp) = sigYield;
epspN.at(imp) = epsN - sigYield / EN;
plState.at(imp) = 1;
} else {
sigN.at(imp) = sigTrial;
plState.at(imp) = 0;
}
// add the contribution of the microplane to macroscopic stresses
for ( int i = 1; i <= 6; i++ ) {
answer.at(i) += N [ imp - 1 ] [ i - 1 ] * sigN.at(imp) * microplaneWeights [ imp - 1 ];
}
}
// multiply the integral over unit hemisphere by 6
answer.times(6);
// update status
status->letTempStrainVectorBe(totalStrain);
status->letTempStressVectorBe(answer);
status->letTempNormalMplaneStressesBe(sigN);
status->letTempNormalMplanePlasticStrainsBe(epspN);
status->letPlasticStateIndicatorsBe(plState);
}
void
M1Material :: giveRealStressVector_PlaneStress(FloatArray &answer,
GaussPoint *gp,
const FloatArray &totalStrain,
TimeStep *tStep)
{
int i, imp;
FloatArray sigmaN, deps, sigmaNyield;
double depsN, epsN;
answer.resize(3);
answer.zero();
sigmaNyield.resize(nmp);
sigmaNyield.zero();
M1MaterialStatus *status = static_cast< M1MaterialStatus * >( this->giveStatus(gp) );
this->initTempStatus(gp);
sigmaN = status->giveNormalMplaneStresses();
if ( sigmaN.giveSize() < nmp ) {
sigmaN.resize(nmp);
sigmaN.zero();
}
deps.beDifferenceOf( totalStrain, status->giveStrainVector() );
for ( imp = 1; imp <= nmp; imp++ ) {
depsN = N.at(imp, 1) * deps.at(1) + N.at(imp, 2) * deps.at(2) + N.at(imp, 3) * deps.at(3);
epsN = N.at(imp, 1) * totalStrain.at(1) + N.at(imp, 2) * totalStrain.at(2) + N.at(imp, 3) * totalStrain.at(3);
sigmaN.at(imp) += EN * depsN;
double sy = EN * ( s0 + HN * epsN ) / ( EN + HN ); // current microplane yield stress
if ( sy < 0. ) {
sy = 0.;
}
if ( sigmaN.at(imp) > sy ) {
sigmaN.at(imp) = sy;
}
sigmaNyield.at(imp) = sy;
for ( i = 1; i <= 3; i++ ) {
answer.at(i) += N.at(imp, i) * sigmaN.at(imp) * mw.at(imp);
}
}
// update status
status->letTempStrainVectorBe(totalStrain);
status->letTempNormalMplaneStressesBe(sigmaN);
status->letNormalMplaneYieldStressesBe(sigmaNyield);
status->letTempStressVectorBe(answer);
}
