Inertia Modulated Meta-structure with Time-Varying Inertia Amplification

In this work, a new inertia modulated meta-structure is proposed to enable time-dependent inertia parameters, and thereby realize non-reciprocal wave propagation via spatiotemporal modulation. The designed cell structure is composed of an oscillatory disk and a mass that slides in a guide embedded in the disk frictionlessly with prescribed motion. Effective moment of inertia and damping coefficients of the rocking motion of the cell structure are rendered time-dependent due to the inertia and Coriolis forces of the periodically sliding mass, which allows us to implement the expected spatiotemporal modulation upon a super-cell. Non-reciprocal propagation behavior of the proposed meta-structure is verified via theoretical solution of the dispersion relation as well as dynamic response of a finite array. Effects of modulation parameters, including the frequency, amplitude, and phase, on the unidirectional propagation characteristic are thoroughly investigated.