孔的形状和排列方式对厚孔板微结构压膜空气阻尼的影响分析

本文对微结构上孔的形状和排列方式对压膜空气阻尼的影响进行了理论和模拟分析.理论研究表明对于不同厚度、不同排列方式下的孔单元阵列,若孔的总面积和孔单元面积均为常数,当孔数增加到某一值时有最小阻尼力,并用FEM工具ANSYS证明了该结论的正确性.结果还表明孔数对恒定尺寸微结构空气阻尼的影响随着结构厚度和孔数的增加而变得更加明显.分析结果对比表明在同样的尺寸条件下,孔方形排列微结构的空气阻尼小于孔蜂窝式排列微结构的空气阻尼,该现象随着孔单元面积的增加变得越明显,但是随着孔单元接近微结构的边界,阻尼之间的差距减小.研究结果可以用在高精度MEMS器件如MEMS地震检波器、MEMS光开关和MEMS红外光传感器等的优化设计中去.

The effects of hole shapes and array forms on the squeeze-film air damping of thick perforated microstructures

Squeeze-film air dampings of thick perforated microstructures with hole arrays in different forms have been studied analytically and numerically by changing the shapes of holes and the areas of hole cells. Analytical results show that there are the minimum air damping forces for oscillating perforated microstructures with different values of thickness and array forms of hole at some values of hole number in the conditions that the total areas of holes and hole ceils are constant, respectively, which is approved by FEM analysises. The results also show that the influence of the number of hole on air damping becomes more evident with an incease of the thickness or hole number of a constant lateral dimensions microstructure. The analyzed results contrast also shows that the air damping of a microstructure whose etched holes array in square is smaller than that of a microstructure whose etched holes array in hexagon in the same dimensions conditions, and the phenomenon is more obvious with an increase of the area of a hole cell. But as the hole cells are approaching the fringe of the microstructure, the predominance is reducing. The studied resuits can be applied in the optimization of the design of MEMS devices such as high precision aeeelerometers, optical MEMS switches, MEMS infrared optical sensors.