On the dynamics of a nonlinear energy harvester with multiple resonant zones
On the dynamics of a nonlinear energy harvester with multiple resonant zones
复制标题
DOI：
10.1007/s11071-018-4124-2
复制
发表时间：
2018-02
影响因子：
5.6
通讯作者：
P. Alevras;S. Theodossiades;H. Rahnejat
中科院分区：
文献类型：
--
作者：
P. Alevras;S. Theodossiades;H. Rahnejat
本文通过谐波平衡法和数值分析方法研究了一种用于旋转系统的非线性振动能量采集器的动力学特性。电磁采集器连接到一个匀速旋转的轴上。采用磁悬浮作为系统的非线性恢复力，拓宽了振子的谐振范围。该系统被建模为一个Duffing振荡器与静态下的线性频率变化，以及谐波激励。行为图表和骨干曲线提取的基波响应和验证对选定的情况下，使用直接数值积分的频率响应曲线。结果发现，刚度的变化，以及不对称的强迫，产生了一种新的结构的多个谐振区，将单稳态和双稳态动力学。与先前考虑的双稳态能量采集器相反，跨阱振荡通过从单阱势能到具有前向频率扫描的双阱的过渡来实现。此外，井内振荡呈现硬化行为，不同于双稳态Duffing振荡器的众所周知的软化井内响应。分析表明，所提出的系统具有多个谐振响应的频率扫描，连续相互作用的骨干曲线类似于一个多模态系统的影响。向双稳态动态的转变和硬化井内振荡的这种组合效应引起采集器在多个不同频率范围内的谐振响应。因此，该系统表现出加宽的频率响应，增强了其能量收集潜力。
The dynamics of a nonlinear vibration energy harvester for rotating systems is investigated analytically through harmonic balance, as well as by numerical analysis. The electromagnetic harvester is attached to a spinning shaft at constant speed. Magnetic levitation is used as the system nonlinear restoring force for broadening the resonant range of the oscillator. The system is modelled as a Duffing oscillator with linear frequency variation under static, as well as harmonic excitation. Behaviour charts and backbone curves are extracted for the fundamental harmonic response and validated against frequency response curves for selected cases, using direct numerical integration. It is found that variation in stiffness, together with asymmetric forcing, gives rise to a novel structure of multiple resonant zones, incorporating mono-stable and bi-stable dynamics. Contrary to previously considered bi-stable energy harvesters, cross-well oscillations are realized through a transition from single-well potential energy to double-well with forward frequency sweep. Furthermore, in-well_oscillations present a hardening behaviour, unlike the well-known softening in-well response of bi-stable Duffing oscillators. The analysis shows that the proposed system has multiple resonant responses to a frequency sweep, influenced by consecutive interacting backbone curves similar to a multi-modal system. This combined effect of the transition to bi-stable dynamics and the hardening in-well oscillations induces resonant response of the harvester over multiple distinct frequency ranges. Thus, the system exhibits a broadened frequency response, enhancing its energy harvesting potential.