Solutions for lamellar inhomogeneities in an infinitely extended isotr
opic solid subjected to a uniform stress field at infinity are obtaine
d by using Eshelby's equivalent inclusion method. First, two limiting
cases are studied: cracks (i.e. inhomogeneities with elastic moduli id
entically zero), and anticracks (i.e. inhomogeneities with infinitely
large elastic moduli). Solutions are obtained for different modes of u
niform loading in plane strain (biaxial load and in-plane shear), and
anti-plane strain. It is observed that the stress field of an anticrac
k under biaxial load has an inverse square root singularity at the tip
of the anticrack. The stress held arises from the contribution of a p
lanar dislocation distribution and a dislocation dipole distribution.
Finally the most general case of inhomogeneities with finite non-zero
elastic moduli, which here are called quasicracks, is considered and n
ew solutions are provided. Quasicracks are useful to model fibers in f
iber-reinforced materials. Analytical solutions are provided for the s
tress held in the matrix, including the interface shear stress.