Non-reciprocal Dynamic Response of a Bilinear Lattice

We report on the non-reciprocal dynamics of a one-dimensional bilinear lattice subject to continuous harmonic excitation. The bilinear nature of the lattice is due to elements within the unit cell that have different elastic moduli in compression and extension. We investigate the asymmetric wave propagation characteristics of bilinear lattices, and explain the results based on the nonlinear dynamics of the unit cell. We show that we can obtain different responses for the forward and backward configurations relying on either (i) the harmonic (frequency-preserving) operating range, or (ii) different onsets of instability. We discuss experimental realization of the unit cell based on 3D-printed macroscale structures.