Dislocation pileups: topological features of stresses and strains

When averaged over half-spaces, the elastic stress and strain fields from dislocation pileups are shown to take a peculiar topological features of the form y/\y\, i.e., they undergo an abrupt change when passing through the pileup plane. The average fields appear to be equivalent to the Somigliana dislocations and provides a description of strain boundaries in crystals such as the torsion boundary which represents a surface where the average rotation field experience a topological jump. (C) 2001 Published by Elsevier Science Ltd.