Multistage oscillators for ultra-low frequency vibration isolation and energy harvesting

Limited by the mass, stiffness, barrier height and natural frequency of the oscillator, the existing structure or mechanism is still difficult to achieve vibration suppression and effective utilization under ultra-low frequency excitation. In particular, it is difficult to break through the technical bottleneck of the integration and intelligence of vibration isolation and energy harvesting (VTEH). The introduction of nonlinearity is usually used to solve the problem of ultra-low frequency, and the integration problem can be overcome through electromechanical coupling. Therefore, the purpose of this article is to reveal and deeply explore the geometric nonlinearity and electromechanical coupling of multistage oscillators for ultra-low frequency VTEH. This kind of multifunctional oscillators can be realized by combining mechanical multistage coupling and electromechanical conversion technologies. The experimental results confirm the development of multistage theory, and the results show that, especially in the case of multi-coupling structures, the multistage oscillators with high-order quasi-zero stiffness can effectively reduce the initial frequencies of vibration isolation and the frequencies corresponding to the maximum output power. The theoretical and experimental results in this paper show that the multistage oscillators are suitable for VTEH of ultra-low frequency sources.