  We investigate the damping enhancement in a class of biomimetic staggered
composites via a combination of design, modeling, and experiment. In total,
three kinds of staggered composites are designed by mimicking the structure of
bone and nacre. These composite designs are realized by 3D printing a rigid
plastic and a viscous elastomer simultaneously. Greatly-enhanced energy
dissipation in the designed composites is observed from both the experimental
results and theoretical prediction. The designed polymer composites have loss
modulus up to ~500 MPa, higher than most of the existing polymers. In addition,
their specific loss modulus (up to 0.43 $Km^2/s^2$) is among the highest of
damping materials. The damping enhancement is attributed to the large shear
deformation of the viscous soft matrix and the large strengthening effect from
the rigid inclusion phase.
