Computational two-scale homogenization of periodic masonry: Characteristic lengths and dispersive waves

The wave propagation along the orthotropy axes in both the running bond and English bond masonry is analyzed by considering wave-lengths multiple of periodic cell size. Dispersive waves propagating along the orthotropy direction parallel to the mortar joints are characterized by velocities that differ quite markedly from the corresponding ones in the classical continuum and this difference increases with the increase of the stiffness mismatch between the brick and mortar. Conversely, along the direction perpendicular to the mortar joints the velocity of the shear waves is approximately equal to that in the classical equivalent continuum. These findings show the qualitative similarity of the mechanical behavior of masonry with layered materials.