int
M1Material :: giveIPValue(FloatArray &answer, GaussPoint *gp, InternalStateType type, TimeStep *tStep)
{
M1MaterialStatus *status = static_cast< M1MaterialStatus * >( this->giveStatus(gp) );
if ( type == IST_PlasticStrainTensor ) {
FloatArray plasticStrain(3);
plasticStrain.zero();
FloatArray sigmaN = status->giveTempNormalMplaneStresses();
FloatArray strain = status->giveTempStrainVector();
double Exx, Eyy, Gamma;
Exx = Eyy = Gamma = 0.;
if ( sigmaN.giveSize() == nmp ) {
for ( int imp = 1; imp <= nmp; imp++ ) {
double epsN = 0.;
for ( int i = 1; i <= 3; i++ ) {
epsN += strain.at(i) * N.at(imp, i);
}
double epsNpl = epsN - sigmaN.at(imp) / EN;
double aux = epsNpl * mw.at(imp);
Exx += aux * N.at(imp, 1);
Eyy += aux * N.at(imp, 2);
Gamma += aux * N.at(imp, 3);
}
}
plasticStrain.at(1) = 1.5 * Exx - 0.5 * Eyy;
plasticStrain.at(2) = -0.5 * Exx + 1.5 * Eyy;
plasticStrain.at(3) = 4. * Gamma;
StructuralMaterial :: giveFullSymVectorForm( answer, plasticStrain, gp->giveMaterialMode() );
return 1;
} else {
return StructuralMaterial :: giveIPValue(answer, gp, type, tStep);
}
}
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;
}
