圆平膜片弹性特性分析与优化设计

针对圆平膜片在传统设计中存在的计算繁琐、效率低下和精度不高等缺陷,应用ANSYS建立圆平膜片有限元模型,并提出圆平膜片弹性特性分析与优化设计的方法. 该方法用ANSYS仿真分析周边固支圆平膜片的弹性特性以及弹性体应力和位移分布情况;通过对圆平膜片的应力、应变及其静态和动态特性的计算,研究弹性体结构尺寸参数和载荷对弹性特性的影响规律;通过对模型的优化设计,使圆平膜片的性能指标得到进一步优化,弹性元件的设计精度得到提高.该方法对于仪器仪表中圆平膜片的参数优化设计具有一定指导意义和实用价值.     

三轴线加速度计E膜片弹性体应力应变解析法研究

基于E型膜片已设计出一种三轴线加速度计;此E型膜片的敏感弹性部分为圆环平膜片,对其应力应变特性的分析至关重要.考虑到E膜片的实际尺寸及测量时其变形较小,将E膜片变形作为薄板小挠度变形来对待,对z、x(y)各轴向加速度载荷az、ax(az)作用下,膜片的边界条件进行分析;并参考圆薄板轴对称/反轴对称变形的弹性曲面微分方程及通解,获得E膜片的应力应变解析解.     

自确认压力传感器结构设计

自确认传感器能够实现传感器故障的自诊断和自恢复,除了提供被测量的确认的测量值之外,还提供测量值的不确定度、测量值的状态等表征传感器输出可信度的参数,可以实时了解传感器的工作状态,及时采取相应的措施,大大提高监测系统的可靠性.本文针对自确认圆平膜片应变式压力传感器的设计,分析了圆平膜片的应力和应变分布,建立了圆平膜片上两种传统布片方式的数学模型,在分析圆平膜片压力传感器故障模式的基础上,对传统的布片方式进行了改进,建立了在圆平膜片上进行多组布片的方案,为实现自确认圆平膜片应变式压力传感器提供了坚实的基础.     

基于优化设计的印制板组件精细化动力学建模方法

以模态测试结果作为修正的目标值,提出了采用ANSYS优化设计对螺栓连接型印制板组件进行精细化动力学建模的方法.首先使用ANSYS概率设计模块计算出印制板组件特征值对结构材料参数的灵敏度.然后基于灵敏度分析结果与螺栓连接处的建模误差,使用ANSYS优化设计模块对印制板组件进行参数修正,最后通过比较不同边界条件下组件的固有特性验证了修正后参数的有效性.研究表明:基于灵敏度分析和建模误差的优化设计方法可以有效提高螺栓连接型印制板组件动力学模型的建模精度.     

应力隔离法在蓝宝石压力传感器结构设计中的应用

对硅-蓝宝石硅压力传感器C型弹性膜片接头结构和E型弹性膜片接头结构进行建模分析,优化设计应力隔离槽结构,并应用于硅-蓝宝石压力传感器一体化设计的弹性膜片与接头结构.较好地解决了硅-蓝宝石压力传感器的零点输出、满量程输出在不对称安装应力下产生偏移,影响传感器的测量精度的问题,使传感器的安全性、可靠性进一步提高,优化结构后的传感器在航天领域具有广泛的应用.     

压力传感器波纹膜片设计的力学性能分析

利用ANSYS有限元软件,对压力传感器波纹膜片的有关结构参数与力学性能的关系进行了分析:对均布载荷和集中载荷作用下,波纹膜片中心位移的有限元解与解析解进行了比较,验证有限元模型和结果的精度;根据ANSYS分析结果,对不同型面结构的波纹膜片,比较波纹形状对膜片力学性能的影响;讨论了正弦型波纹膜片的膜片厚度、波纹高度、波纹数目对其性能的影响,为波纹膜片结构的优化设计提供依据.     

ANSYS在高精度压力传感器感压膜片结构分析中的应用

ANSYS作为最通用最有效的有限元软件之一,在计算数学、计算力学和计算工程科学领域都得到了的广泛的应用.本文正是利用ANSYS软件强大的有限元分析功能,对压力传感器感压膜片在一定压力下变形情况进行分析,实现感压膜片的应力分析.     

波纹膜片的设计方法研究

波纹膜片是一种环状同心波纹的圆形膜片,是差压传感器的核心零件。针对传统膜片设计计算方法存在的计算工作量大、误差大、周期长、费用高、难以计算膜片在受力状态下的应力分布情况等缺点,以经典的膜片压力特征方程为理论依据,辅以有限元分析方法,对膜片进行设计。对基于该方法设计的膜片进行一系列的测试和验证。结果表明,与传统设计方法相比,该方法不仅缩短了膜片的设计周期、提高了设计精度,而且满足了传感器对膜片的特性要求,对于类似膜片的设计具有一定的参考意义。     

基于ANSYS的水下金刚石绳锯机导向轮弹性轴的优化设计

针对水下金刚石绳锯机串珠绳张力传感器的设计需要,提出了基于ANSYS的张力传感器弹性轴的优化设计,建立了优化设计数学模型,分析了ANSYS的优化设计方法,完成了基于ANSYS的弹性轴优化设计过程,最终得到了满足弹性轴体积最小时的优化设计尺寸.     

自确认压力传感器结构参数设计及其有限元分析

设计了自确认压力传感器弹性体的结构参数,包括弹性体的材料选择,弹性体的形状、厚度和半径,建立了应变片在弹性体上的多组布片方案,为压力传感器实现自确认功能奠定了基础.应用有限元分析软件ANSYS对所设计的传感器弹性体进行了动、静态分析,获得了弹性体在受力情况下的位移、应力、应变分布状态,并且计算了弹性体的固有频率,分析结果表明,所设计的弹性体满足自确认压力传感器的设计要求.     

微型高温压力传感器芯片设计分析与优化

基于弹性力学和板壳力学理论,分析了微型高温压力传感器圆形膜片的受力分布,为力敏电阻在应变膜上的布置提供依据;利用有限元分析方法,借助ANSYS仿真软件,对微型高温压力传感器应变膜进行了一系列的分析和计算机模拟,探讨了传感器圆形应变膜简化应力模型的合理性以及温度对应力差分布的影响,得到了直观可靠的结果,为微型高温压力传感器芯片设计和研发新颖的微型高温压力传感器芯片提供有力的依据.     

Design and pressure analysis for bulk-micromachined electrothermal hydraulic microactuators using a PCM

Paraffin wax exhibits a volumetric expansion of ∼15%, at around its melting point. By exploiting this phenomenon, high performance bulk-machined electrothermal hydraulic microactuators have been demonstrated. The microactuators have been integrated into microfluidic valves, microgrippers and micropipettes. The paraffin wax is confined within a bulk-micromachined silicon container. This container is sealed using an elastic diaphragm of PDMS, while it is heated via gold microheaters located on an underlying glass substrate. All the layers used to make up the containers are bonded together using a unique combination of overglaze paste and PDMS. The hydraulic pressure of expanding paraffin wax was determined using the deflection theory of a circular plate. For the first time, the hydraulic pressure of expanding paraffin wax was calculated using the theory of large deflections for a circular plate and measured data from the type-A microgripper. This theory has been exploited for the deflection analysis of micromachined thin elastic diaphragms. In order to calculate the hydraulic pressure, the theory of large deflections of a circular plate is calculated using the measured actuation height, the PDMS diaphragm dimension of the microgripper (type-A) and mechanical properties of the PDMS. The hydraulic pressure was calculated to be approximately 0.12 MPa. All the devices were successfully demonstrated and operated at either 10 or 15 V.     

用激光束成像法测量双E型硅弹性膜应变

用激光束成像法对双E型传感器的硅弹性膜应变进行的研究,测出了该弹性膜的应变情况,此方法对其它结构形式的敏感芯片应变的研究也有一定的参考价值。     

FBAR-on-diaphragm type electro-acoustic resonant micro-accelerometer: a theoretical study

We presented a theoretical study of the performance of a novel FBAR-on-diaphragm sensor-head structure for the FBAR-based electro-acoustic resonant micro-accelerometer. This structure overcomes disadvantages in the FBAR-beam structure for its limited cantilever beam thickness, and deficiencies in the embedded-FBAR structure for its complex micro-fabrication process. Its elastic diaphragm is made of silicon dioxide (SiO₂)/silicon nitride (Si₃N₄) bilayer film, which is not only more susceptible to the IC compatible integration process for the Si-based microstructure and the FBAR, but also improves sensitivity and temperature stability of the BAW accelerometer. FBAR-on-diaphragm type BAW accelerometer integrates the acceleration sensing structure, i.e., the SiO₂/Si₃N₄ bilayer diaphragm and the Si proof-mass, with the AlN FBAR electro-acoustic transducer. Preliminary performance analysis on FBAR-on-diaphragm type BAW accelerometer suggests that the FBAR-on-diaphragm structure is feasible. We obtained modal frequencies of the FBAR-on-diaphragm structure and stress distribution of the diaphragm under 0–100 g acceleration loads through the finite element modal analysis and static simulation, Applying the calculated maximum stress to the piezoelectric film in FBAR for qualitative analysis, and combining the dependency of elastic coefficient on stress in the Wurtzite AlN film calculated with the first-principle method, we roughly predicted the maximum elastic coefficient variation in the Wurtzite AlN film under different acceleration load. With the help of the RF simulation software ADS, we changed the longitudinal wave velocity corresponding to the elastic constants with variant acceleration loads. By comparing the resulted resonant frequencies of the sensor head without and with different acceleration loads, we qualitatively characterized its frequency shift and sensitivity. In our study, we gave further analysis of the simulation results. It reveals that the first-order modal frequency of the SiO₂/Si₃N₄ circular diaphragm is quite far away from the higher ones, which means less cross modal coupling. It also reveals that under the acceleration load, its resonant frequency with a quite linear acceleration–frequency shift characteristic will up-shift with the sensitivity of several KHz/g.     

Dynamical modeling and experimental validation of a micro-speaker with corrugated diaphragm for mobile phones

As the design trend of modern cellular phones evolves to be miniaturization and versatile sound in quality, the electro-mechanical components including the micro-speaker are essential toward size reduction and broad frequency range of sound. To reduce size, a diaphragm type micro-speaker is commonly employed in industry, while to broaden the sound frequency range corrugations on the diaphragm are adopted. The corrugations are generally capable of leading to fairly flat response over a broad range since diaphragm stiffness is decreased in axial direction. To confirm the aforementioned capability, the modeling on a corrugated diaphragm is performed first using finite element method (FEM) to obtain the associated dynamic equations in terms of modal coordinates; then the equations are next combined with the magneto-electrical model of the voice coil motor (VCM) that is attached to the bottom side of the diaphragm. Finally, the acoustic effects of the air inertia on the diaphragm and vents of the outer case are modeled using basic acoustic theories. Assembling all derived system equations and solving them, the frequency response of the micro-speaker in sound pressure level (SPL) can be simulated. It shows that the diaphragm corrugation in fact helps flatten the SPL response of the micro-speaker (especially in high frequency range) to lessen sound distortion. Furthermore, the corrugation angle approximately below 45° is favored over other angles or flatter SPL response. Experiments are also conducted to verify the theoretical findings.     

Analysis of fluid flow and deflection for pressure-balanced MEMS diaphragm valves

Based on the linear plate theory for an elastic thin plate and the Bernoulli equation for a steady incompressible and inviscid fluid flow, the effect of fluid flow on the deformation of microelectromechanical systems (MEMS) diaphragm valve is investigated both analytically and numerically. For a given configuration of diaphragm valve, a relationship between the applied pressure and resulting contact area between diaphragm and valve seat is derived. Possible instability of such a system under the pressure-balanced mechanism is demonstrated with both analytical and numerical solutions for the deflection. Deflection as a function of flow speed, radius of outlet orifice, inlet gap, and bending stiffness of diaphragm are presented. In addition, the effect of diaphragm making contact with the valve seat due to pressure differential and fluid flow is analyzed and a relation between the contact zone and the external pressure is obtained. The results of the analysis suggest important parameters in the design of MEMS diaphragm valves and can be used as a basis in the design of such valves.     

具有自由悬浮敏感膜的硅微机械电容式麦克风的设计与仿真计算

提出了一种具有自由悬浮敏感膜和带孔铜底板的硅微机械电容式麦克风.采用低压化学汽相淀积工艺制作而成的复合敏感膜一端固定于硅基,其余部分处于自由悬浮状态,可以释放敏感膜的内应力.底板采用铜电镀技术制作,底板上呈蜂窝状分布的圆形通气孔用来调节敏感膜与底板间的空气压膜阻尼.仿真计算表明在5 V偏置电压下麦克风灵敏度为10.62 mV/Pa,工作稳定最大电压为9.7 V,工作频率带宽为0～10.57 kHz.分析结果表明该微机械麦克风能满足市场需求.     

Optimization design of multi-material micropump using finite element method

This paper presents a micropump fabricated from low cost materials with specific goal of cost reduction. The micropump does not require any valve flap and comprises one plastic pump polyether–ether–ketone (PEEK) body, one metal diaphragm, and three piezoelectric ceramics to form piezoelectrically actuated diaphragm valves. The valve actuation simplifies micropump structural designs and assembly processes to make the pump attractive for low cost bio-medical drug delivery applications. A detailed optimization design of geometric parameters of the piezoelectrically actuated diaphragm is undertaken by use of 3D finite element method (FEM) to maximize piezoelectric actuation capability and ensure actuation reliability. An optimized geometric dimensional design: the ratio of thicknesses between the piezoelectric ceramics and the metal diaphragm, and the lateral dimension of the piezoelectric ceramic, is obtained through simulations. Based on the optimized design, a good agreement has been reached between simulated and measured strokes of the micropumps. The tested results show that the micropump has a high pump flow rate for air, up to 39 ml/min, and for water, up to 1.8 ml/min, and is capable of ensuring diaphragm’s maximum stress and strain is within material strength for reliable work.     

Design of MEMS PZT circular diaphragm actuators to generate large deflections

This paper presents a design of lead zirconate titanate (PZT) circular diaphragm actuators to generate large deflections. The actuators utilize a unimorph structure consisting of an active PZT and a passive thermally grown SiO/sub 2/ layer. The diaphragm structures were formed by deep reactive ion etching (DRIE). Two different designs, where the PZT layer in the diaphragm actuators was driven by either interdigitated (IDT) electrodes or parallel plate electrodes, were investigated. Both finite element analysis and experimental results proved that the IDT configuration is favorable to generate deflections larger than the diaphragm thickness. The IDT configuration creates an expansion in the PZT layer in the radial direction and a contraction in the tangential direction under forward bias, which enables large deflections. At applied voltages of 100 V, an actuator 800 /spl mu/m in diameter could generate center deflections of around /spl sim/7.0 /spl mu/m, significantly greater than the diaphragm thickness of 2.8 /spl mu/m. The deflection profiles for the diaphragm actuators became flatter when an inactive region in the annular IDT configuration was introduced. There was also a proportional reduction of the maximum deflection.     

Computer aided design of post-tensioned concrete reservoirs

A computer method based on the classical shell and plate theories is presented for the elastic analysis of cylindrical water tanks subjected to axisymmetrical loading and post-tensioning loads. A spherical dome or circular plate roof, cylindrical container, top and bottom ring beams together with a circular plate foundation are considered as possible components of a water tank in the flexibility formulation. Classical shell, plate, and ring beam theories are used to obtain flexibility coefficients. A computer program has been developed based on this formulation and successfully used in the design of post-tensioned concrete water tanks with diameters of 80 m built in Saudi Arabia.