Windows Environment for User Programmable Features As soon as Abaqus/CAE starts, it creates a file called abaqus.rpy on the Abaqus default directory. By locating this file you will know which is the Abaqus default directory in your installation. When Abaqus starts, it reads the file abaqus_v6.env from c:\simulia\abaqus\6.xx\site. To enable F90 functionality, copy the file abaqus_v6.env to the Abaqus default directory. Then, edit the copy of abaqus_v6.env to add the keyword '/free' to the compiler directive, as shown below. It is best to add '/free' to your own copy of abaqus_v6.env--do not replace the compiler directive with the example line below, ad '/free' to the compiler directive on your copy of abaqus-v6.env. compile_fortran=['ifort', '/c','/DABQ_WIN86_64', '/recursive', '/Qauto-scalar', '/QxW', '/nologo', '/Od', '/include:%I', '/free'] For Abaqus to accept user code, you must have Intel Fortran 11.1, and the Visual Studio (VS) 2008 shell that comes with it, installed. The VS 2008 shell that comes with Fortran 11.1 is all you need but having the full VS 2008 adds functionality. If you want to use the full VS 2008, you have to install VS before installing Fortran to get Fortan integrated into VS. In either case, you must upgade VS 2008 to SP1 or better. The upgrade is free and available on the web. Using VS 2008, you should debug your UMAT befroe trying it out with Abaqus. A simple umat_tester.f90 is avalable in \cite{feacm-abaqus} to help you. You can modify it to suit your needs. Once you modify the compiler directive, UMAT code can be written in F90 format, as long as the file name given to Abaqus has an extension .for. Since F77 is very limited, I prefer to use F90. Unfortunately, Visual Studio requires F90 code to have an extension .f90. Therefore, once the .f90 code is debugged, you have to copy it to a file with extension .for. UMAT, VUMAt, UGENS, and UEL examples in Abaqus documentation are writenn in F77. A free converter, written in F90, is available in \cite{Metcalf}, mirored in \cite{feacm-abaqus}. Next, you have to modify the WIN7 environment variables so that Abaqus can find the ifort compiler, linker, and Fortran libraries needed. Basically, you have to add to the User variables and System variables. You may not need all that is lited below, and you may have more things in your WIN7 environment than listed below, because of other software installed on your computer. To access WIN7 environment, do the following: Click WIN7 Start, right-click Computer, Properties, Advanced system settings, Advanced, Environment. Then, modify your WIN7 environment to get something similar to the following: User variables: INCLUDE: %IFORT_COMPILER11%\Include;%IFORT_COMPILER11%\Include\Intel64 LIB: %IFORT_COMPILER11%\Lib\intel64;%MSVS9.0%\VC\Lib;%MSVS9.0%\VC\PlatformSDK\Lib PATH: C:\Program Files (x86) System Variables: IFORT_COMPILER11: C:\Program Files (x86)\Intel\Compiler\11.1\048 INTEL_LICENSE_FILE: C:\Program Files (x86)\Common Files\Intel\Licenses MSVS9.0: C:\Program Files (x86)\Microsoft Visual Studio 9.0 PATH: C:\Program Files\Microsoft HPC Pack 2008\Bin\; C:\Program Files (x86)\Common Files\Microsoft Shared\VSA\9.0\VsaEnv;%IFORT_COMPILER11%\mkl\em64t\bin; C:\SIMULIA\Abaqus\Commands;%IFORT_COMPILER11%\Bin\intel64; %MSVS9.0%\VC\Bin; VS90COMNTOOLS: c:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\Tools\ Michael Metcalf, A tool to convert f77 source code to f90, ftp://ftp.numerical.rl.ac.uk/pub/MandR/convert.f90