Dear everyone,

Using Abaqus 2021.HF7, I conduct simulations using an advanced Fortran UMAT subroutine which works fine on Linux platforms. However, since I started running the very same jobs on windows (with a working Fortran compiler and the same subroutine etc.), I encounter inconsistent job executions, meaning sometimes the job completes fine and sometimes, after a certain step increment, the process aborts:

***ERROR: TOO MANY ATTEMPTS MADE FOR THIS INCREMENT

Usually, when changing parameters of the material model, the error occurs still after the very same integration step (usually somewhere in the first quarter of the applied force curve) when using the same remaining model settings. However, after restarting Abaqus or the PC, the very same job sometimes completes consistently. This not only happens with one certain setup but with many different geometries and load cases. Also, the computation speed is generally very low (it should run should be much faster than with the older linux computer, but is actually much slower).

I tried to exclude any external influences; there also doesn't seem to be a difference whether I start a job from the Abaqus GUI or via the console, also analysis or interactive mode lead to the same irregular weird behavior (inconsistent when e.g. restarting the console: sometimes it completes, sometimes it crashes as stated above).

Again, I would like to mention that on Linux, using the same Abaqus version, this issue does not occur at all: there, all jobs complete at any time.

Is such an issue known regarding irregular errors occuring especially on windows platforms when using certain UMATs or is there even a solution? I appreciate any suggestions and help!

Kind regards,
Lu

Abaqus ​​​​​​​