| 引用本文: | 许静,马靖轩,王路文,连加俤,蔡林烜,董林玺.石墨烯柔性压阻传感器微织构压缩应变机制[J].中国表面工程,2024,37(1):169~178 |
| XU Jing,MA Jingxuan,WANG Luwen,LIAN Jia,CAI Lin,DONG Linxi.Compressive Strain Mechanism of Micro-texture of Graphene Flexible Piezoresistive Sensor[J].China Surface Engineering,2024,37(1):169~178 |
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| 石墨烯柔性压阻传感器微织构压缩应变机制 |
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许静1, 马靖轩1, 王路文2, 连加俤3, 蔡林烜1, 董林玺4
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1.杭州电子科技大学机械工程学院 杭州 310018;2.浙大城市学院信息与电气工程学院 杭州 310015;3.中国计量大学机电工程学院 杭州 310018;4.杭州电子科技大学电子信息学院 杭州 310018
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| 摘要: |
| 为满足智能机器人、电子皮肤等领域对柔性传感器高灵敏度日益增加的需求，通过设计高表面积形貌以制备石墨烯凸台微织构柔性传感器，并对比分析有无微织构传感器的灵敏度；基于结构力学方程与静电方程，建立微织构柔性传感器模型， 开展了电场作用不同基底厚度以及微织构间距下柔性传感器微织构应变的数值模拟，研究柔性压阻传感器微织构压缩应变机制，探寻机械载荷和电载荷的交互作用关系。结果表明，柔性基底的微织构化处理能有效提高柔性压阻传感器的灵敏度。模型总位移的最大值随基底厚度的增加呈非线性增加，微织构应变随着厚度的增加而减小。电场作用下微织构应变受机电耦合压力叠加的影响均大于无电场作用。框状微织构类似于悬臂梁，作用在微织构上的力矩随间距增加而增大，同时刚度减小， 微织构的压缩形变增加，应变增大。组合尺寸微织构的应变随着微织构间距的增加而增大，制备多尺寸微结构传感器可使用 （150+350）μm 的组合尺寸，能够有效增加接触面积提高传感器灵敏度。机械载荷和电载荷的耦合作用，组合尺寸对力矩与刚度的分配有效增加了基底的应变，提高了柔性传感器的灵敏度。 |
| 关键词: 柔性传感器 数值模拟 电场 超弹性材料 接触模型 |
| DOI：10.11933/j.issn.1007-9289.20220107001 |
| 分类号:TP212 |
| 基金项目:国家自然科学基金（52275182）；浙江省自然科学基金（LTGS23E060002）；浙江省属高校基本科研业务费专项资金（GK229909299001-14）；高端装备界面科学与技术全国重点实验室自由项目开放基金（SKLTKF22B02） |
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| Compressive Strain Mechanism of Micro-texture of Graphene Flexible Piezoresistive Sensor |
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XU Jing1, MA Jingxuan1, WANG Luwen2, LIAN Jia3, CAI Lin1, DONG Linxi4
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1.School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018 , China;2.School of Information and Electrical Engineering, Hangzhou City University, Hangzhou, 310015 , China;3.School of Mechanical Engineering, China Jiliang University, Hangzhou 310018 , China;4.School of Electronic Information, Hangzhou Dianzi University, Hangzhou 310018 , China
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| Abstract: |
| The flexible pressure sensor is gradually replacing traditional sensors owing to its high sensitivity, strong flexibility, implantability, wearability and other characteristics, and has become a research hotspot at home and abroad in recent years. To meet the increasing demand for highly sensitive flexible sensors in intelligent robots, electronic skin and other fields, considering the working mechanism that converts external physical stimuli into electrical signals and increasing the contact area as the entry point, a flexible pressure resistance sensor substrate is designed and processed into the frame convex micro-structured, which take PDMS as the base and graphene as the conductive function layer. The experiment results show that the micro-texture can improve the sensitivity of the flexible sensor, and the sensitivity is five times that of the non-micro-texture sensor. This is because when the micro-texture is subjected to external pressure, it produces compressive deformation, which increases the contact area of the substrate, resulting in reduced resistance and increased sensitivity of the sensor. To deeply study the mechanism of the compressive strain of the microtexture, the microtexture flexible sensor model is established, and a numerical simulation of the microtexture strain of the flexible sensor under the influence of electric field action is conducted based on the structural mechanical equation and electrostatic equation. The numerical simulation results of the microstructure strain of the flexible sensor in different substrate thicknesses, microstructure sizes, and combined size microstructures under the presence of an electric field are compared. The calculated results show that for the thickness of the different microstructures, the model total displacement maximum increases nonlinearly with the substrate thickness and the microtexture strain decreases with the thickness. Owing to the elastic potential energy stored by PDMS, the total displacement of the microtexture surface increase is less than the increase of the thickness, causing a decrease in the microstructural strain. Under the experimental conditions with the electric field, the stress variables of the microtexture are greater than those without the electric field. The maximum value of the micro-texture strain was 4.953×10?10 and the minimum value was 3.018×10?10 without the electric field. The maximum strain was 5.515×10?10 and the minimum was 3.297×10?10 with the electric field. This is caused by the influence of electromechanical coupling, which concentrates the electric field, and the superposition of pressure on the microtexture adds the strain. For different microstructure spacing, the strain of the microtexture increases with the spacing. This is because the frame microtexture is similar to the cantilever beam, where the moment acting on increases with the increased spacing while the stiffness decreases, and the increased compressive deformation of the microtexture leads to increased strain. For different combinations of microstructure sizes, the strain of the combined size micro-textures increases with the increase of the total spacing of the microtextures. This is because according to the torque distribution method, the greater the pressure on the torque of the small and micro-texture, the greater the spacing of the large and micro-texture, the greater the transmission torque. When the micro-texture distance increases from 300 μm to 500 μm, the micro-texture strain increases by 1.6×10?11 in the absence of the electric field, and the micro-texture strain increases by 1.78×10?11 in the electric field. When the micro-texture distance increases from 500 μm to 700 μm, the increase is 0.98×10?11 under the action of the electric field. Therefore, the decrease of the micro-texture stiffness of a small size leads to a decrease in the overall micro-texture stiffness and increases the overall strain. The preparation of multi-size microstructure sensors can use a combined size of (150+350) μm, which can effectively increase the contact area and improve the sensitivity of the sensors. In conclusion, reducing the thickness of the microstructure base and increasing the spacing of the microstructure can increase the sensitivity of flexible sensors. |
| Key words: flexible sensor numerical simulations electric fields superelastic materials contact model |
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