I recently gave a presentation with the title Advanced User-Material Modeling of Cather Kinking
at the ANSYS Regional Conferences in Boston on Oct 15, 2010. In this presentation I discussed some of my recent ANSYS simulation work (using UserMat subroutines) related to geometric instabilities of catheters. Like Abaqus, ANSYS supports the use a advanced user-material models and the PolyUMod library
is now available for both Abaqus and ANSYS.