void
TensorMechanicsPlasticMohrCoulombMulti::perturbStress(const RankTwoTensor & stress, std::vector<Real> & eigvals, std::vector<RankTwoTensor> & deigvals) const
{
Real small_perturbation;
RankTwoTensor shifted_stress = stress;
while (eigvals[0] > eigvals[1] - 0.1*_shift || eigvals[1] > eigvals[2] - 0.1*_shift)
{
for (unsigned i = 0; i < 3; ++i)
for (unsigned j = 0; j <= i; ++j)
{
small_perturbation = 0.1*_shift*2*(MooseRandom::rand() - 0.5);
shifted_stress(i, j) += small_perturbation;
shifted_stress(j, i) += small_perturbation;
}
shifted_stress.dsymmetricEigenvalues(eigvals, deigvals);
}
}
void
TensorMechanicsPlasticTensileMulti::dyieldFunction_dstressV(const RankTwoTensor & stress, const Real & /*intnl*/, std::vector<RankTwoTensor> & df_dstress) const
{
std::vector<Real> eigvals;
stress.dsymmetricEigenvalues(eigvals, df_dstress);
if (eigvals[0] > eigvals[1] - 0.1*_shift || eigvals[1] > eigvals[2] - 0.1*_shift)
{
Real small_perturbation;
RankTwoTensor shifted_stress = stress;
while (eigvals[0] > eigvals[1] - 0.1*_shift || eigvals[1] > eigvals[2] - 0.1*_shift)
{
for (unsigned i = 0; i < 3; ++i)
for (unsigned j = 0; j <= i; ++j)
{
small_perturbation = 0.1*_shift*2*(MooseRandom::rand() - 0.5);
shifted_stress(i, j) += small_perturbation;
shifted_stress(j, i) += small_perturbation;
}
shifted_stress.dsymmetricEigenvalues(eigvals, df_dstress);
}
}
}
