Hello,
I use MSC Marc with the subroutine hypela2. I use Total Lagrange where
the material tangent stiffness C is dS/dE = C. (2nd Piola Kirchoff to
Green Lagrange Strain). MSC Marc requires 36 components of the material
tangent stiffness operator (assuming it is left and right symmetric because 2nd Piola Kirchoff and Green Lagrange are so).
But my stiffness matrix is not (due to martensitic transformation). I would
like to use unsymmetric material stiffness. My question: How do you
implement an unsymmetric material tangent in MSC Marc? (with 81
distinctive components). I lose
quadratic convergence rate when I make the material tangent stiffness
symmetric.
Regards,
Rowan Laarhoven