Hi Wolfgang
The stress tensor for this problem is symmetric (small strain
elastoplasticity) but in general it need not be.
I have not implemented the complementary mixed formulation where
stress is one of the unknowns in deal.ii yet. If I were to use deal.ii
as it is presently I would have set up the FESystem as follows (roughly)
fe(
FE_Q<deal_II_dimension>(2), 6), // six stress components
FE_Q<deal_II_dimension>(2), 1)); // scalar plastic multiplier
and then used the FEValuesExtractors as follows
// generate stress and plastic mutliplier shape function views
const FEValuesExtractors::Scalar plastic_mult(6);
std::vector<FEValuesExtractors::Scalar> stress;
for (unsigned int alpha = 0; alpha < 6; alpha++) {
stress.push_back(FEValuesExtractors::Scalar(alpha));
}
I would like to be able to generate tensorial output for
visualisation. So I will give that ago as well.
regards
Andrew
On 02 Sep 2009, at 5:21 PM, Wolfgang Bangerth wrote:
Andrew,
as a postscript to my previous mail: I don't know what you use to
generate
output, but VTK has the ability to plot tensor-valued data. If you
wanted to
do that, you'd probably also have to extend the
DataComponentInterpretation
mechanism that tells DataOut which variables are scalars, vectors,
or in your
case tensors. That is independent of the extractors, however, and
you'll be
able to implement them separately if you wanted to do that.
As for tensors in general: Are your stress tensors not symmetric? If
they are,
do you implement them as 6-component (in 3d) objects, or as full
unsymmetric
9-component object?
Best
W.
-------------------------------------------------------------------------
Wolfgang Bangerth email: [email protected]
www: http://www.math.tamu.edu/~bangerth/
_______________________________________________
dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
