Abstract
Capacitive pressure sensors which convert pressure into electric signals are a kind of highly efficient and reliable sensor and have wide applications. The flexible structure of capacitive pressure sensors may undergo large deformation, and the sensitivity and linearity with respect to the deformation are two major performance indices of capacitive pressure sensors. Thus, a simple and accurate analytical model to predict the deformation and electromechanical coupling under external pressure is essential for the quantitative design of the sensors. In this paper, we propose an electromechanical analytical model which couples the capacitance change under large deformation of the flexible curved electrodes. The theory is used to predict the deformation and capacitance of a flexible rhomboidal capacitive sensor, and is verified by both numerical simulations and experiments. The electromechanical analytical model can be applied to other cantilever-like capacitors with symmetric flexible/curved electrodes under symmetric loading. The theory can degenerate into the existing analyses in the literature for the case of small deformation. The accurate analytical model can facilitate design and analyses of capacitive pressure sensors and other similar structures.
摘要
电容式压力传感器是一种将压力转换成电信号的高效可靠的传感器, 具有广泛的用途. 柔性电容式压力传感器的结构可能会发 生较大的变形, 大变形下的灵敏度和线性度是柔性压力传感器的主要性能指标, 无法用传统小变形理论进行分析. 因此, 建立能够准确 预测外部压力下柔性压力传感器的变形和力-电耦合性能的理论模型对传感器的定量设计至关重要. 在本文中, 我们提出了一个力-电 耦合理论模型, 分析了柔性电极在弯曲大变形下的电容变化. 该理论被用来预测柔性菱形电容式传感器的变形和电容变化关系, 并通 过数值模拟和实验进行了验证. 该力-电耦合理论可用于对具有对称柔性/弧形电极的悬臂式电容器在对称载荷作用下的力-电性能进 行分析和设计, 并可退化为文献中的小变形理论. 准确的理论分析模型可以促进电容式压力传感器和其他类似结构的研究和设计.
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Acknowledgements
This work was supported by the National Natural Science Foundation of China (Grant No. 12272020), and Beijing Natural Science Foundation (Grant No. JQ21001).
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Methodology, Investigation, Writing–original draft. Tianyu Wang: Validation, Investigation, Writing–review & editing, Visualization. Li-Hua Shao: Conceptualization, Methodology, Writing–review & editing, Supervision, Project administration, Funding acquisition.
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Song, W., Wang, T. & Shao, LH. Analytical model for large deformation and capacitance of rhomboidal pressure sensors and experimental verification. Acta Mech. Sin. 39, 122497 (2023). https://doi.org/10.1007/s10409-023-22497-x
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DOI: https://doi.org/10.1007/s10409-023-22497-x