In a single crystal containing dislocations, the elastic strain defined by a linear constitutive
law from the stress tensor can be written as the sum of a symmetric gradient and a solenoidal
tensor
,
called the dislocation strain. This latter part of the elastic strain is related to
dislocations since its incompatibility equals the curl of the contortion. The aim of this
paper is to derive a time-evolution law for the internal thermodynamic variable
,
arising from the second law of thermodynamics, and to discuss its mathematical
setting. This encompasses a discussion on the functional space used and about the
equation’s well-posedness. A fourth-order time-dependent nonlinear PDE involving
the incompatibility operator is found, which is similar in form to the Cahn–Hilliard
equation, and represents in this respect a tensor generalization for solenoidal
fields.
Keywords
dislocations, linear elasticity, incompatibility,
Cahn–Hilliard, evolution law, second principle