MEMS开关关键技术研究

发布时间：2018-01-10 02:19

本文关键词：MEMS开关关键技术研究　出处：《西安电子科技大学》2013年博士论文　论文类型：学位论文

【摘要】：MEMS开关中,受表面效应的影响,黏着力对开关触点的工作可靠性有极大的影响。本文以固体力学、弹塑性力学和黏着力学为基础,建立触点微／纳米量级的弹性和塑性接触模型;基于量子力学研究了触点的隧道电流机理,建立了在弹-塑性变形条件下粗糙表面触点间的隧道电流和接触电阻计算模型；基于机电动力学原理设计了一种永磁微加速度开关。研究内容如下： (1)基于Lennard-Jones势能定律和Hamaker假设,通过积分方法得到球体与平面间的黏着力,结合经典弹性理论计算了纳米级刚性球体和弹性平面的黏着接触变形,对常见金属触点材料在弹性接触时接触力、接触变形、接触面积等参数的变化规律进行了仿真分析。 (2)对污染触点进行了接触研究,模拟分析了金表面沉积碳膜后,触点的弹性接触力、接触变形、接触面积等参数的变化规律。 (3)建立了表面黏着接触应力计算模型。采用von Mises强度理论研究弹性平面屈服问题,得到了塑性变形区域和塑性变形量。 (4)给出了弹性和塑性区域的变形准则,基于该准则模拟分析球体下压过程中球-面间隙和接触面积的变化规律。以Au材料为例,计算了球体下压过程中材料的应力-应变关系并得到Au材料的微观屈服极限。 (5)建立了触点塑性接触模型,基于该模型对清洁和污染触点接触过程中接触压力、接触应力、表面变形量及接触面积等参数的变化规律进行了仿真分析,得到了接触表面的引力区域、斥力区域；弹性变形区域和塑性变形区域。 (6)基于隧道电流密度计算公式,推导了刚性球形触点趋近刚性平面时隧道电流和接触电阻的计算公式,并进一步给出了刚性接触时触点的收缩面积和截面收缩率随触点间隙的变化规律。 (7)建立了刚性球形触点和弹-塑性平面电接触的计算模型,研究了弹性和塑性变形对触点的接触力、隧道电流、接触电阻的影响。 (8)将触点表面微丘的曲率半径和高度误差量按照正态分布选取,建立了粗糙表面电接触模型；研究了微丘半径,高度误差和微丘数量对接触电阻的影响。得到典型触点接触电阻随接触力及接触压强变化的规律。 (9)给出一种永磁微加速度开关的结构设计方案,提出了该开关的静态设计原则。建立了微型运动平板间空气阻尼的计算模型。推导了MEMS微平面机构所受的空气阻尼力和阻尼系数的解析公式。 (10)基于典型粗糙表面电接触计算模型,给出了触点稳定工作时接触压力-接触电阻和电流-电压关系曲线。 (11)建立了开关动力学分析模型,对开关在激励下的工作响应进行了仿真。
[Abstract]:Based on the solid mechanics , the elastic - plastic mechanics and the adhesive force theory , the elastic and plastic contact model of the contact micro / nano scale is established . Based on the quantum mechanics , the tunneling current and the contact resistance calculation model between the contact points are established . A permanent magnet micro - acceleration switch is designed based on the principle of the machine electrodynamics . The research contents are as follows : ( 1 ) Based on Lennard - Jones potential energy law and Hamaker assumption , the adhesive force between the sphere and the plane is obtained by integral method . According to the classical elastic theory , the adhesion contact deformation of the nano - rigid sphere and elastic plane is calculated , and the rule of contact force , contact deformation and contact area of the common metal contact material is simulated and analyzed . ( 2 ) The contact study of pollution contact is carried out , and the law of elastic contact force , contact deformation and contact area of the contact is simulated after the carbon film has been deposited on the gold surface . ( 3 ) The calculation model of contact stress on the surface is established . The yield problem of elastic plane is studied by von mises strength theory , and the plastic deformation area and plastic deformation amount are obtained . ( 4 ) The deformation criterion of elastic and plastic regions is given . Based on the criterion , the rule of ball - surface gap and contact area in the process of ball pressing is simulated . Taking Au material as an example , the stress - strain relationship of the material in the process of pressing the ball is calculated and the micro yield limit of Au material is obtained . ( 5 ) The contact plastic contact model is established . Based on the model , the contact pressure , contact stress , surface deformation amount and contact area are simulated and analyzed . The contact surface ' s attractive area , repulsive force area , elastic deformation area and plastic deformation area are obtained . ( 6 ) Based on the calculation formula of tunneling current density , the calculation formula of tunnel current and contact resistance in rigid spherical contact approaching rigid plane is deduced , and the change law of the contact ' s shrinkage area and the cross - section shrinkage ratio with the contact gap is further given . ( 7 ) The calculation model of electrical contact between rigid spherical contact and elastic - plastic plane is established , and the influence of elastic and plastic deformation on the contact force , tunnel current and contact resistance of the contact is studied . ( 8 ) selecting the radius of curvature and the height error of the microhills of the contact surface according to the normal distribution , establishing a rough surface electrical contact model , and researching the influence of the micro - dome radius , the height error and the number of the microhills on the contact resistance , and obtaining the rule of the contact resistance of the typical contact with the contact force and the contact pressure . ( 9 ) The design scheme of the permanent magnet micro - acceleration switch is given , and the principle of static design of the switch is put forward . The calculation model of the air damping between the micro - motion plates is established . The analytical formula of the damping force and damping coefficient of the MEMS micro - plane mechanism is deduced . ( 10 ) Based on the typical rough surface electrical contact calculation model , the contact pressure - contact resistance and the current - voltage relationship curve of the contact stability operation are given . ( 11 ) The model of switch dynamics is established , and the working response of the switch under excitation is simulated .

【学位授予单位】：西安电子科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH-39

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