Hello everyone;

I have implemented the Sanisand constitutive model (UMAT) in abaqus in the scope of performing a dynamic analysis on a 3D soil-pile interaction problem. I have succeded in defining the initial parameters in the manner as described in the Sanisand readme delivered within the Umat package.

Currently, i was wondering about an error that is keeping to pop out in the .log file when running a job with the above mentioned Sanisand Umat.

The dispaly errors are (i) and (ii) as follows :

(i) Subroutine INTERSECT_DM – bisection

err = 4233.87844492903

ERROR: max no. of iterations exceeded

Subroutine INTERSECT_DM – bisection

err = 2108.86530036459

mario_2 = one

attempt number 1

accept solution

(ii) mario_DT – kRk_1, mario10=one, pp_kk= 1.051068305969238E-003

Note the following errors are still poping out in the .log file until that the .log file remains unchanged in terms of size.

What is mainly the problem with the Subroutine INTERSECT_DM ? Is there any technical explination that may help to understand what is causing such an error ?

Thank you for helping me with this issue

Best regards

Tags: abaqus sanisand step increment UMAT
(i) The first error message may represent that after the maximum number of iterations, ABAQUS still cannot find the intersection point of the yield surface.

(II)The second error message mean Kp<0 or LDeR<0