How do I use VUMAT in ABAQUS?

Your answer is really really general and even though I don’t fully comprehend what you want, I will try to explain the process in as greater detail as I can. There are many steps to this process.

1. You will have to setup Abaqus to use your UMATs and VUMATs which are essentially fortran subroutines. This means you will have to tell abaqus where it can find a fortran compiler to convert your fortran programs into object code and use it. For windows you will have to use the proprietary ‘Intel fortran’ compiler which, last time I hear (2014) was for about $500 for use in an academic setting. The price might be higher if its a private firm. Mind you, for using this compiler, you have to have ‘MS Visual studio’ installed. I am not sure if you require the professional version or the free version but I am sure it works in the pro version.
   The process of making this work can prove difficult but there are scores of articles about this on the internet. You should take a look at them.
   
   I found a way to use the subroutines on a linux machine with Abaqus by using the free fortran compiler ‘gfortran’. There are articles about this on the internet and it involves editing your environment file. If OS is not a constraint, you should definitely try this route. Even if you have windows, you can install a virtual machine and run linux on your windows machine. Install abaqus on that linux and use gfortran to run your subroutines.
   
   Once you have installed everything, you can check if the process was successful.
   In the abaqus command window, type
   
   abaqus verify -user_std
2. Abaqus will reply with a success message if it found a compiler that it can work with.
3. Once you have successfully set up #1, you can move to writing the subroutine. I personally use this:
   
   http://imechanica.org/files/Writ...
4. After writing the user subroutine and making sure that the fortran file and the input file reside in the same directory, you can run your jobs using this command

abaqus job=my_analysis user=my_subroutine

1. where, my_analysis is the input file name and my_subroutine is the fortran file containing your subroutine.