Help regarding RVE calculations under constant stress triaxiality condition

Hi all,

I want to do RVE analysis under constant stress triaxiality condition in ABAQUS. I am following a recent paper (http://www.sciencedirect.com/science/article/pii/S0020768314003424) which explains the procedure using spring elements and user defined MPC. I have written user defined MPC and trying to check it with single element, but I am not getting correct results. I have checked my calculations for MPC. I think I am missing somewhere in modelling part. I have attached mpc script (mpc.txt) and single element ABAQUS input file(single_3d.txt) . It will be great help if someone can help me out of the problem.

with regards,

Thanks,

Anshul