Complexity Digest 2001.11 - 07
12-Mar-2001
Pattern Formation: Spiral Cracks Without Twisting, Nature
Abstract: A fascinating class of patterns, often
encountered in nature as meandering cracks on rocks, dried-out
fields and tectonic plates, is produced by the fracture of solids.
Here we describe the observation and modelling of an unusual type
of pattern consisting of spiral cracks in fragments of a thin
layer of drying precipitate. We find that this symmetry-breaking
cracking mode arises naturally not from twisting forces, but from
a propagating stress front induced by the fold-up of the
fragments.