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);
}
void
M1Material :: givePlaneStressStiffMtrx(FloatMatrix &answer, MatResponseMode rMode, GaussPoint *gp, TimeStep *tStep)
{
answer.resize(3, 3);
if ( rMode == ElasticStiffness ) {
giveElasticPlaneStressStiffMtrx(answer);
return;
}
M1MaterialStatus *status = static_cast< M1MaterialStatus * >( this->giveStatus(gp) );
FloatArray sigmaN = status->giveTempNormalMplaneStresses();
if ( sigmaN.giveSize() != nmp ) {
sigmaN = status->giveNormalMplaneStresses();
if ( sigmaN.giveSize() != nmp ) {
giveElasticPlaneStressStiffMtrx(answer);
return;
}
}
FloatArray sigmaNyield = status->giveNormalMplaneYieldStresses();
double D11, D12, D13, D22, D23, aux;
D11 = D12 = D13 = D22 = D23 = 0.;
for ( int imp = 1; imp <= nmp; imp++ ) {
if ( sigmaN.at(imp) < sigmaNyield.at(imp) ) { // otherwise the plane is yielding
aux = mw.at(imp) * EN;
} else if ( sigmaNyield.at(imp) > 0. ) {
aux = mw.at(imp) * EN * HN / ( EN + HN );
} else {
aux = 0.;
}
D11 += aux * NN.at(imp, 1);
D12 += aux * NN.at(imp, 3);
D13 += aux * NN.at(imp, 2);
D22 += aux * NN.at(imp, 5);
D23 += aux * NN.at(imp, 4);
}
answer.at(1, 1) = D11;
answer.at(1, 2) = answer.at(2, 1) = answer.at(3, 3) = D12;
answer.at(1, 3) = answer.at(3, 1) = D13;
answer.at(2, 2) = D22;
answer.at(2, 3) = answer.at(3, 2) = D23;
}
