Characterization of challenges in asymmetric nonlinear vibration energy harvesters subjected to realistic excitation
Characterization of challenges in asymmetric nonlinear vibration energy harvesters subjected to realistic excitation
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DOI：
10.1016/j.jsv.2020.115460
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发表时间：
2020-09
影响因子：
4.7
通讯作者：
Wen Cai;R. Harne
中科院分区：
文献类型：
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作者：
Wen Cai;R. Harne
随着物联网（IoT）的爆炸式发展，振动能量收集提供了一种环保的解决方案，以取代消耗性电池为物联网无线传感器供电。然而，在实践中实施时，环境振动输入能量的周期性比以前的研究中所采用的假设少得多。考虑到非线性器件平台中不可避免的不对称性，这变得尤为重要。这项研究揭示了这些复杂的挑战，实际的振动能量收集的开发和探索的分析模型的基础上等效线性化。建模方法提供了一个机会，了解不对称性，非线性和组合激励响应的能量采集器的直流功率输送的影响。在分析模型中，加权高斯联合分布被用来近似随机激励引起的影响。结合数值计算和试验验证，分析表明，随着随机基底加速度的增加，可能出现两种结果。第一个结果涉及通过触发大幅值非线性振荡来增强DC功率。第二个结果对应于高功率输送的损失，因为噪声干扰了快速通过动态的实现。减小非对称性或增加谐波激励分量都有利于诱导功率增强动力学，抑制第二种情况的发生。虽然简化的高斯分布，分析框架不能重现在每种情况下的动态响应的精确细节，结果表明，分析的统计趋势在模拟和实验中得到了全面的证实。这表明本研究的新建模可能有助于指导人们注意实际组合激励环境中非线性振动能量采集器的设计和部署技术，其中精确制造或放置的限制可能会引入结构不对称性。
With an explosion of the internet of things (IoT), vibration energy harvesting provides an environmentally friendly solution to replace consumable batteries in powering IoT wireless sensors. Yet, when implemented in practice, ambient vibration input energy is much less periodic than assumptions adopted in previous studies. This becomes especially important given that asymmetries are inevitable in nonlinear device platforms. This research sheds light on these complex challenges of practical vibration energy harvesting by developing and exploring an analytical model based on equivalent linearization. The modeling approach provides an opportunity to understand influences of asymmetry, nonlinearity, and combined excitation response on the DC power delivery of energy harvesters. In the analytical model, a weighted Gaussian joint distribution is utilized to approximate the influences caused by the random excitation. Combined with numerical and experimental validation, the analysis indicates that with the increase of stochastic base acceleration, two outcomes are possible. A first outcome involves an enhancement of DC power by way of triggering large amplitude nonlinear oscillations. A second outcome corresponds to a loss of high power delivery since the noise interferes with the attainment of the snap-through dynamic. Either reducing asymmetry or increasing harmonic excitation component is found to be favorable to induce the power-enhancing dynamics and inhibit the occurrence of the second case. Although with the simplified Gaussian distribution, the analytical framework cannot reproduce exact details of the dynamic responses in every case, the results show that the statistical trends of the analysis are overall borne out in simulation and experiment. This indicates the new modeling of this research may help guide attention to design and deployment techniques for nonlinear vibration energy harvesters in practical combined excitation environments, where limitations on precise manufacture or placement may introduce structural asymmetry.