This chapter discusses additional user programs that can be run with Abaqus. It provides an overview of the following enhancements:

• “Define viscous and structural matrices via user subroutine UINTER,” Section 14.1

• “Define fluid exchange via user subroutines VUFLUIDEXCHEFFAREA and VUFLUIDEXCH,” Section 14.2

• “Utility routines to obtain principal stress/strain values and directions in Abaqus/Explicit,” Section 14.3

• “Utility routines to obtain parallel processes information,” Section 14.4

• “New location option for saving plug-ins created with the Really Simple GUI (RSG) Dialog Builder,” Section 14.5

• “Utility routine to obtain the volume fraction in Eulerian elements,” Section 14.6