defects

The geometric formulation of continuum mechanics provides a powerful approach to understand and solve problems in anelasticity where an elastic deformation is combined with a non-elastic component arising from defects, thermal stresses, growth effects, or other effects leading to residual stresses. The central idea is to assume that the material manifold, prescribing the reference configuration for a body, has an intrinsic, non-Euclidean, geometric structure. Residual stresses then naturally arise when this configuration is mapped into Euclidean space.

Article published in Journal of the Mechanics and Physics of Solids

In the theory of dislocations, the Burgers vector is usually defined by referring to a crystal structure. Using the notion of affine development of curves on a differential manifold with a connection, we give a differential geometric definition of the Burgers vector directly in the continuum setting, without making use of an underlying crystal structure.

(to appear in International Journal of Fracture; Proceedings of the 5th Intl. Symposium on Defect andMaterial Mechanics)

Amit Acharya and Claude Fressengeas

There will be a mini-symposium entitled "Defects and Microstructure at the Nanoscale and Beyond," at the USNCCM-10 conference in Columbus, OH, July 16 -19, 2009.  This topic is of keen interest to the I-Mechanica community and we hope many of you will join us there. Our goal is to bring together researchers from the mechanics, materials, and physics communities to cross-fertilize research on defect-mediated processes in microstructural evolution, with a focus on both hard and soft materials.