  The aim of this paper is to provide new results and insights for a screw
dislocation in functionally graded media within the gauge theory of
dislocations. We present the equations of motion for dislocations in
inhomogeneous media. We specify the equations of motion for a screw dislocation
in a functionally graded material. The material properties are assumed to vary
exponentially along the x and y-directions. In the present work we give the
analytical gauge field theoretic solution to the problem of a screw dislocation
in inhomogeneous media. Using the dislocation gauge approach, rigorous
analytical expressions for the elastic distortions, the force stresses, the
dislocation density and the pseudomoment stresses are obtained depending on the
moduli of gradation and an effective intrinsic length scale characteristic for
the functionally graded material under consideration.
