UEXPAN

I am having problems in writing the umat and uexpan subroutines applicable to the creep model defined in 

http://ascelibrary.org/doi/abs/10.1061/%28ASCE%29ST.1943-541X.0000375

Has anybody written the algorithm? 

Hi,

I have a thermo-mechanical constitutive model for polymer and want to implement it in ABAQUS through two user subroutines namely UMAT and UEXPAN but I dont know how to use them together. Also, in UEXPAN, I need to pass in the strain tensor as information but I dont see 'STRAN' variable in the list of variables passed in to UEXPAN in Abaqus documentation. Does anyone know answer to this?

Thanks,

Mandar