  We study in this work a system of granular disks enclosed in a rectangular
region. Granular disks are arranged, at high particle density, in a hexagonal
lattice. Specifically, we are interested in the conditions for mechanical
signal transmission. Two different potentials are considered. Our results are
obtained by means of soft disks computer simulations. We analytically determine
the eigenfrequencies spectra of the system from the corresponding Hessian
matrix. Alternatively, the eigenfrequencies can also be obtained from the time
evolution of molecular dynamics simulations. Previous works have shown that
mechanical signal transmission in granular matter can be used to develop
acoustic switches. Our results reveal that the working range of the granular
switch changes dramatically for different interaction models. In particular,
strong anisotropies in signal transmission may appear for certain interparticle
forces.
