Print to file in Vumat

13.2.1 USER SUBROUTINES: OVERVIEW

Testing and debugging
When developing user subroutines, test them thoroughly on smaller examples in which the user
subroutine is the only complicated aspect of the model before attempting to use them in production
analysis work.
If needed, debug output can be written to the ABAQUS/Standard message (.msg) file using
FORTRAN unit 7 or to the ABAQUS/Standard data (.dat) file or the ABAQUS/Explicit status (.sta)
file using FORTRAN unit 6; these units should not be opened by your routines since they are already
opened by ABAQUS.
FORTRAN units 15 through 18 or units greater than 100 can be used to read or write other userspecified
information. The use of other FORTRAN units may interfere with ABAQUS file operations;
see “FORTRAN unit numbers used by ABAQUS,” Section 3.6.1. You must open these FORTRAN units;
and because of the use of scratch directories, the full pathname for the file must be used in the OPEN
statement

also:
3.6.1 FORTRAN UNIT NUMBERS USED BY Abaqus
Abaqus uses the FORTRAN unit numbers outlined in the table below. Unless noted otherwise, you should not try to write to these FORTRAN units from user subroutines.
For Abaqus/Standard, you should specify unit numbers 15–18 or unit numbers greater than 100 .
For Abaqus/Explicit, specify units 16–18 or unit numbers greater than 100 ending in 5 to 9, e.g. 105, 268, etc. You cannot write to the.sta file.

here is an example:

IF (condition fulfilled) THEN
   open(15,file='Exp.rpl',position='append')
   write(15,*) TIME(2), RPL
   close(15)
END IF

write to log file:
IF (condition fulfilled) THEN
    print*, NDI
END IF

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Ruhr-University
Bochum
Germany