Bistability in a symmetric out-of-plane microstructure
Bistability in a symmetric out-of-plane microstructure
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对称面外微观结构的双稳定性
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
C. Harnett
中科院分区：
文献类型：
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作者：
T. Lucas;D. Porter;J. Beharic;T. Berfield;C. Harnett
我们研究了应变金属/氧化物微结构的机械双稳性，这些微结构除了在一个中心附着点之外都是从衬底上释放的。这些器件的平面布局是对称的，但当结构从衬底上释放时，对称性被打破。残余应力导致每个结构沿着两个90°轴之沿着从衬底卷曲。这种结构表明，只要没有塑性变形，结构就可以被固定，但只能通过完全压平、约束和重新释放装置。我们通过仿真和实验研究了其他切换路径。ANSYS中的有限元建模表明，该装置可以通过施加单点力在形状之间可逆地切换。实验表明，可逆的，可重复的开关也可以通过基板平面中的气流的分布力来实现，其中较大的器件以较慢的流速进行开关。实验表征的边缘长度在700和550微米之间的装置显示在2-5 m/s的气流速度范围内切换，阈值流速由装置的高度和投影面积决定。这些表面加工的微器件可以用作机械记忆单元、被动阈值传感器和峰值流量事件的存档器。
We studied the mechanical bistability of strained metal/oxide microstructures that were released from the substrate except at a central attachment point. The devices’ planar layout was symmetric, but the symmetry was broken when the structures were released from the substrate. Residual stress caused each structure to curl up from the substrate along one of two 90° axes. This configuration suggested that the structures could be bistable as long as there was not plastic deformation—but only by completely flattening, constraining and re-releasing the device. We investigated other switching paths by simulation and experiment. Finite element modelling in ANSYS showed that the device could be reversibly switched between shapes by applying a single point force. Experiments showed that reversible, repeatable switching could also be achieved by the distributed force of gas flow in the plane of the substrate, with larger devices switching at slower flow velocities. Experimentally characterized devices with edge lengths between 700 and 550 microns showed switching in the airflow velocity range of 2–5 m/s, with the threshold flow rate governed by the height and projected area of the device. These bistable surface-machined microdevices could serve as mechanical memory cells, passive threshold sensors, and archivers of peak flow events.