A multi-directional multi-stable device: Modeling, experiment verification and applications

Multi-stable vibration energy harvester based on spring-mass system has received widespread attention from many researchers, because the spring-mass multi-stable system has the advantages of low natural frequency, simple structure and high output power. This work considers such a energy harvesting system, but with the additional novelty of using the link mechanism to improve the bistable smooth and discontinuous (SD) oscillator, and a multi-directional multi-stable device (MMD) is proposed. Equilibrium analysis demonstrates the multi-stable mechanism and the bifurcation conditions for the unperturbed system. While for the perturbed system, the Extended Averaging Method is carried out to demonstrate the multi-stable behaviors, transitions between different potential wells, and their large amplitude inter-well motions. The experimental results are compared to theoretical results. Both theoretical and experimental data suggest that the MMD produces a large amplitude response at ultra-low frequencies, enabling motion throughout all equilibrium positions. The designed prototype can be easily adopted for efficient energy harvesting from ultra-low frequency vibration sources. © 2020 Elsevier Ltd.