I have updated this again to improve file writing and calculations of principal and mises. This is done in a solver call PlasticSolver. PlasticSolver is ElasticSolver with the addition of calculations of principal and mises and output to files called output_stress.txt and output_strain.txt. It only does it for one specified integration point on one specified element.
The UMATmises_yield.F90 works with ElasticSolver, but only mormal stress and strain will be output.
UMATmises_yield.F90 with PlasticSolver will output the above.
PlasticSolver is built by
elmerf90 PlasticSolve.F90 -o PlasticSolve
and callrd in the sif by
Procedure = "PlasticSolve" "ElasticSolver"