ABAQUS is commerical software program used across deciplines for finite element analysis. ABAQUS has a vast support available in terms of user reference manuals, support forums, and training videos.

Limited guidance and support is available publicly on development of user subroutines. The problems faced during running a subroutine and their solutions are presented here.

This is the first step that needs to be completed to test your subroutines (e.g., UMAT, UEL). This step can sometime be really tedious and time-consuming. Following links describe in detail the steps that you will need to follow to link a user subroutine with ABAQUS. Procedure might be little different for your case depending on your ABAQUS version, computer specific information etc. You might need to adapt the procedure appropriately to suit your needs. Two documents on the same topic is available, one by myself and another by A B M Tahidul Haque (PhD Candidate, University at Buffalo). Users are suggested to use the document that suits their need better.

ABAQUS Linking Document by Manish Kumar
HTML Version PDF version

ABAQUS Linking Document by A B M Tahidul Haque
PDF version

Here are two subroutines that I have created in ABAQUS
ElastomericX: User Subroutine for Analysis of Low Damping Rubber (LDR) bearing
LeadRubberX: User Subroutine for Analysis of Lead Rubber (LR) Bearing

Some examples of subroutines available on internet
User element UEL development exampleUser Material UMAT examples available through book: Introduction to computational plasticity
http://www.eng.ox.ac.uk/NP/ICP/ This link contains Fortran codes for many UMATS.