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Modelling and Validation of Electret-based Vibration Energy Harvesters in View of Charge Migration
Zhaoshu Yang,Lihua Tang,Kai Tao,Kean C. Aw 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.1
One of the key problems of electret-based vibration energy harvester (eVEH) modelling is that the surface voltage itself cannot precisely reveal the charge storage characteristics of the electret fabricated by different processes. In this paper, we endeavor to interpret the charge migration mechanism of the eVEH with electrets fabricated by different processes. Based on the above analysis, a unified analytical model of the eVEH is derived accordingly. The dynamic response and voltage output predicted by this model are verifi ed numerically by the equivalent circuit simulation and experimentally with an out-of-plane eVEH prototype. According to the analysis, the maximum power output is approximately 255 μW when the prototype works at its resonance frequency and the vibration amplitude is 1 mm. This paper elucidates the working principle of the eVEH and provides a framework for further theoretical study of eVEHs from the first principle.
Song Shijun,Xiong Chao,Yin Junhui,Yang Zhaoshu,Wang Lu 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.2
In this study, a hierarchical composite Kagome honeycomb sandwich (HCKHS) structure was manufactured based on the interlocking method, and its uniaxial compression performance was explored. Through experiments, the compressive strength, stiffness, energy absorption, and failure process of HCKHS specimens of seven different sizes were determined and compared. Mechanical analytical models were established, and the variation trend in the specific strength was predicted and compared with those of other advanced sandwich structures. The size effect of the HCKHS specimens was analyzed. The influence of a single variable on the core modulus, failure strength, and failure modes was discussed, and failure mechanism maps were drawn. The structure was optimized based on the maximum specific strength and engineering application, and the optimal size design ratio was obtained. The results showed that the HCKHS specimens exhibited excellent compressive properties with a convenient manufacturing process, making them suitable for lightweight applications in engineering. The optimization ideas presented herein are also applicable to other two-dimensional hierarchical or normal composite honeycomb sandwich structures with diamond, triangular, and hexagonal shapes.