Roton-Enabled Mechanical Diode at Extremely Low Frequency

This paper presents a refined model for a mechanical diode based on a mass-spring system. The proposed model utilizes a bilinear spring to construct a frequency converter, which effectively disrupts the reciprocal transmission of acoustic waves. By employing a mass-spring-mass system as a filter, a nonlocal connection is introduced to generate an extremely low-frequency band gap (2–4 Hz), thereby achieving a mechanical diode with a lower operating frequency. The feasibility of these low-frequency mechanical diodes is demonstrated through comprehensive numerical simulations and experimental analyses. In addition, we evaluated the effect of bilinear springs and nonlocal connection parameters on the diode performance.