This paper deals with the propagation of progressive elastic waves in
masonry-like solids. The constitutive equation of masonry-like materials
models the mechanical behavior of materials (such as masonry, rocks
and stones) that do not withstand tensile stresses. The stress function
delivering the Cauchy
stress
corresponding to an
infinitesimal strain tensor
is nonlinear and differentiable on an open subset
W of the set of all
strains. We consider the propagation of small amplitude elastic waves
in a masonry-like body subjected to a given homogenous strain field
belonging to
W. We obtain the propagation condition, which involves the acoustic tensor
(,),
which depends on both
and
the direction of propagation
,
and prove that, due to the presence of cracks, the wave propagation velocities in
masonry are lower than in a linear elastic material.