Oskar Xavier's blog

The implicit implementation of creep in abaqus requires dh/d(\delta \epsilon_c ) as Jacobian in Newton-Raphson's iteration. The derivative can be expanded as shown in the figure attached. The term dh/dq, the one underlined by a green stroke, is expected to be provided by users through specifying DECRA, whereas the term dq/d(\delta \epsilon), underlined by a red one, is confusing me. It seems that that term is computed by Abaqus but I have no idea how it is done. The same question applies to the last derivative on the right hand side.

I wonder if there is any subroutine interface to have access to nodal ( not integral point ) displacement in abaqus DURING the analysis phase.  Suppose I have a field that is going to be used in UMAT and that is dependent on  displacements of all nodes (presumably stored in an array) from the last increment. Is this possible to be implemented within Abaqus?

Thank you all !