 | How can we obtain an arbitrary deformation of anarbitrary body by just repeating and combining some basic deformationprodedures? | ||
| The illustrations shows Volterras answer to thisquestion: Take a cylinder of a material, cut it along some wall, shift thesurfaces of the cut in all ways that - after welding the walls together again(including taking out or adding material) - will lead to different deformationstates. | ||
 | As Volterra showed, there is a limited and rather small numberof possible independent cuts + shifts. All other cuts plus some deformation canalways be expressed as a linear superposition of the elementary cuts. | ||
| Here are the elementary cuts. The first one just shows thecut, the next three ones correspond to dislocations - i.e. a real dislocationproduces exactly the strain field generated by the cut and shift procedure. | ||
| |||
| The last three cuts corresponds to special defects calleddisclinations that are more elementary thandislocations, but are not observed in real crystals (except, maybe, in grainboundaries). They do however, appear in two-dimensional lattices, e.g. in theflux-line lattice of asuperconductor. | ||
5.1.2 Volterra Construction and Consequences
5.2.2 Stress Field of a Straight Dislocation
© H. Föll
To index