[Solved] Solution Dependent Variables (*DEPVAR) in VUMAT

The number and type of Solution Dependent Variables (SDV) depends on the material model. They are typically used to "remember" the state a material point is in between calls to the VUMAT. For viscoplastic material models there are typically the components of the viscoplastic deformation gradient. For hyperelastic materials the stress can be directly calculated from the provided deformation gradient (or stretch tensor), and it is therefore not necessary to use ANY state variables when you code a VUMAT for a hyperelastic material model.

Another use of state variables is to save other values that you are interested in. For example, you can save the first invariant I1, if you like. You can then create history or contour graphs of those state variables.

-Jorgen

Clearly understood. 

Many thanks. 

Melly