A high potential barrier is not conducive to triggering the snap-through motion of a bistable oscillator. The magnetically coupled bistable energy harvester with multiple degrees of freedom, which possesses a considerable bandwidth due to its high-order resonances, also faces the same issue. To address this challenge, a novel magnetically coupled bistable energy harvester with a barrier-decreasing effect is proposed in this study to further enhance the performance in working bandwidth and power generation. The characteristics of co-bistability and variable barrier are skillfully realized by a pair of orthogonal spring oscillators facing a piezoelectric cantilever beam. Firstly, a mathematical model of the harvester is established based on the Euler-Bernoulli beam, linear piezoelectricity, and magnetic dipole theories. Subsequently, the system’s static and dynamic bifurcations, decreasing barrier mechanism, and dynamic responses under swept and stochastic excitations are deeply investigated through numerical simulations, and the key parameters are optimized by intelligent optimization algorithms. Finally, a comprehensive test platform is constructed and the effectiveness of the designed harvester is validated through corresponding experiments. The simulation analyses show that compared with the conventional magnetically coupled bistable energy harvester, the presented harvester can reduce the barrier height by 65%, resulting in an enhancement in effective bandwidth of up to 108%. The power output capacity of the optimized MCBEH-BD is extremely improved under the white-noise excitation. Furthermore, it is found that the experimental results are qualitatively consistent with the numerical outcomes, and they all support the conclusion that the diminution of the potential barrier greatly increases the probability of inducing the potential well escape phenomenon of the piezoelectric beam. Therefore, the proposed harvester with a barrier-decreasing effect has significant superiorities in operating bandwidth and generating capability. The research findings will be beneficial to the advancement of wide-band and low-threshold nonlinear energy harvesters in the future, especially in low-frequency and low-intensity vibration environments.

中文翻译：

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磁耦合双稳态能量采集器的增强宽带性能，具有降低势垒效果


高电位势垒不利于触发双稳态振荡器的突弹跳变运动。具有多自由度的磁耦合双稳态能量收集器由于其高阶谐振而拥有相当大的带宽，也面临着同样的问题。为了应对这一挑战，该文提出了一种具有降低势垒效应的新型磁耦合双稳态能量采集器，以进一步提高其工作带宽和发电性能。共双稳态和可变势垒的特性通过一对面向压电悬臂梁的正交弹簧振荡器巧妙地实现了。首先，基于欧拉-伯努利束、线性压电和磁偶极子理论建立了采集器的数学模型;随后，通过数值仿真深入研究了系统的静态和动态分岔、降低势垒机制以及扫描和随机激励下的动态响应，并通过智能优化算法对关键参数进行优化。最后，构建了一个全面的测试平台，并通过相应的实验验证了所设计的收割机的有效性。仿真分析表明，与传统的磁耦合双稳态能量采集器相比，所提出的采集器可以将势垒高度降低 65%，从而使有效带宽提高高达 108%。优化的 MCBEH-BD 在白噪声激励下的功率输出能力得到了极大的提高。 进一步发现，实验结果与数值结果在质量上是一致的，它们都支持电位势垒的减小大大增加了诱发压电束势阱逃逸现象的概率的结论。因此，所提出的具有降低障碍效应的采集器在工作带宽和发电能力方面具有显著的优势。研究结果将有利于未来宽带和低阈值非线性能量采集器的发展，特别是在低频和低强度振动环境中。