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). But my stiffness matrix is not 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.
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). But my stiffness matrix is not 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.