Broadband vibration reduction through combined linear-nonlinear oscillators in a meta-plate

Abstract

Nonlinear acoustic meta-materials/structures (NAMs) hold great promise for ultra-low and ultra-broadband vibration suppression through chaotic band mechanisms, but at the expense of compromising the original bandgap benefits. To concurrently harness the benefits arising from both bandgaps and chaotic passbands, we propose a dedicated design paradigm in which both linear and nonlinear oscillators are integrated in meta-plates. Harmonic balance method and time-domain integration are utilized to compute the system responses and evaluate the performances of two types of meta-plates. Type I design leverages the complementary benefits of linear acoustic meta-materials/structures (LAMs) and NAMs. The design entails the stability of the bandgap, in which additional 17 dB improvement is achieved over traditional NAMs, while maintaining a stable chaotic band. Type II extends the Type I design, elucidating the influence of nonlinearity location, linear stiffness and damping. Based on the insights gained, broadband vibration suppression has seen a significant extension into the lower frequency range, along with a notable improvement in vibration suppression effectiveness. Our concept is demonstrated experimentally on a meta-plate consisting of linear and vibro-impact nonlinear oscillators. The study alludes to a new route for designing high-performance meta-structures in views of structural vibration control.