  Adding perforations to a continuum sheet allows new modes of deformation, and
thus modifies its elastic behavior. The failure behavior of such a perforated
sheet is explored, using a model experimental system: a material containing a
one-dimensional array of rectangular holes. In this model system, a transition
in failure mode occurs as the spacing and aspect ratio of the holes are varied:
rapid failure via a running crack is completely replaced by quasi-static
failure which proceeds via the breaking of struts at random positions in the
array of holes. I demonstrate that this transition can be connected to the loss
of stress enhancement which occurs as the material geometry is modified.
