Experimental Study on Vibration Reduction Performance of Strongly Nonlinear Vibration Absorption Meta-Structure

A vibration absorption meta-structure with strong nonlinear stiffness is proposed by combining concepts of the vibration absorber and meta-structure. An experimental setup comprising the meta-structure and a primary oscillator is designed. The results of ultraslow linear sweep and fixed-frequency harmonic excitation tests show that the meta-structure can suppress the vibrations of the primary oscillator with different stiffnesses. Moreover, the meta-structure changes the resonance frequency band of the test system to an acceptable range when softer springs are used in the primary oscillator. The primary oscillator and meta-structure have almost the same phase when the resonance occurs, resulting in an acceptable change. Another meta-structure mode is activated as its frequency increases, inducing an additional resonance band when a harder spring is attached. Furthermore, permanent magnets are installed in the meta-structure to form a bistable characteristic, and the influences of the number of magnets on the vibration reduction are analyzed. When the meta-structure has twelve magnets, the high-frequency resonance peak is eliminated because the magnets can suppress the second mode of the meta-structure. The wavelet analysis is conducted to detect the frequency components. The meta-structure results in energy spread from the excitation frequency to the other frequencies.