  We study the propagation of stress waves through ordered 2D networks of
granular chains. The quasi-particle continuum theory employed captures the
acoustic pulse splitting, bending, and recombination through the network and is
used to derive its effective acoustic properties. The strong wave mitigation
properties of the network predicted theoretically are confirmed through both
numerical simulations and experimental tests. In particular, the leading pulse
amplitude propagating through the system is shown to decay exponentially with
the propagation distance and the spatial structure of the transmitted wave
shows an exponential localization along the direction of the incident wave. The
length scales that characterized these exponential decays are studied and
determined as a function of the geometrical properties of the network. These
results open avenues for the design of efficient impact mitigating structures
and provide new insights into the mechanisms of wave propagation in granular
matter.
