There are a number of open-source FEA packages available. See: http://en.wikipedia.org/wiki/List_of_finite_element_software_packages for a list.
Does anyone have experience using any of these? (Thinking esp. of Rezwan … )
If not, I note that FRANC2D and FRANC3D are specifically designed to model crack propagation, which is (maybe?) what we’re trying to do here. Their homepage is at http://www.cfg.cornell.edu/software/franc2d_casca.htm