无力矩马达电液伺服阀

本文介绍用PZT压电元件和PMN电致伸缩元件制作的无力矩马达电液伺服阀。用PMN制做的无力矩马达伺服阀可大大提高动态响应特性。     

基于PZT薄膜的集成式微悬臂梁结构设计与制作

设计了基于PZT压电薄膜的双层和双片压电微悬臂梁结构,利用压电材料的正压电效应和逆压电效应,通过两个压电元件实现传感和执行功能的集成.悬臂梁结构采用体硅加工工艺制作,锆钛酸铅(Pb(Zr,Ti)O3,PZT)压电薄膜采用sol-gel方法在Pt/Ti/SiO2/Si衬底上制作,压电薄膜具有完整的钙钛矿结构和(111)择优取向.为了提高悬臂梁的性能和制作成品率,对制作微悬臂梁的关键工艺进行了优化.     

具有保护功能的集成式路面压电装置的设计与分析

以工程应用为导向,对比分析了三种压电路面实施方案的优缺点,全面分析了埋入式压电元件的失效机理,明确了集成式路面压电装置方案是保护压电元件免于失效的根本措施.在提出集成式路面压电装置设计要求的基础上,设计并制作了一种集成式路面压电装置.采用有限元对该装置的主要部分进行了刚度和强度校核,并进行了碾压实验.结果表明该装置对压...     

基于阻抗技术的压电元件自损伤检测-

为了保证结构健康监测系统的有效运行,基于压电阻抗技术原理,提出了一种压电传感、驱动元件自损伤检测方法.通过研究压电元件等效电容值(压电元件导纳虚部数值)的变化,判别压电元件是否破损及其与主体结构之间是否剥离,并在悬臂梁结构上进行压电元件自损伤检测试验.结果表明,相比压电元件完好的情况,各频率下压电元件电纳值随脱粘部分面积的增加而上升,随破裂部分面积的增加而下降,并且损伤程度和等效电容变化量成比例关系,与理论分析结果吻合较好.     

压电旋转驱动器制作及性能测试

提出了通过控制正压力来改变摩擦力的方案,进而研制了一种以压电叠堆为动力转换元件的新型压电旋转驱动器。采用两个驱动用压电叠堆对称布置的方式设计了该旋转驱动器结构,探讨了旋转驱动器运动机理,制作了压电旋转驱动器试验样机并对其进行了试验测试。试验结果表明,该驱动器输出步长线性度较好,当驱动电压为10 V、频率为2 Hz时,驱动器旋转步长为20 μrad。分析了驱动器输出稳定性,针对存在的问题提出通过施加控制系统来有效提高不同起始位置驱动器的运动稳定性。对试验结果进行误差分析,找出了产生误差的原因,为驱动器的进一步优化设计提供了参考。研究证明了该压电旋转驱动器设计方法的可行性,利用该方法可以制作出结构简单,体积小,适合在微驱动领域中应用的驱动器。     

压电元件在智能结构中的选位及有限元分析

通过对压电薄板的特性分析,建立压电薄板结构的数学模型,并对压电元件在压电智能结构中的布置进行了分析和阐述.通过有限元仿真的方法,进行了模态分析和动态响应分析,进一步阐述了压电元件位置对压电控制效果的影响.     

压电双晶片型微位移放大机构研究

介绍了以压电双晶片作为驱动元件,由三角放大机理构造的柔性铰链机构作为位移输出的微位移放大机构.通过理论计算、建模等对微位移放大机构进行设计,制作了微位移放大机构的样机,并进行了试验.对得到的测试数据进行分析,研究结果表明,采用压电材料作为精密设备的驱动元件性能良好,所研制压电双晶片型微位移放大机构原理,可推广应用到其他...     

蛇型步进式直线驱动器的研究

利用压电陶民电致伸缩性效应可以制成压电驱动器。用金属材料制成的一体化可动结构和叠层式压电元件可组成蛇型步进式直线驱动器,能实现高精度、高可靠性的直线步进驱动。分别地该直线驱动器的系统模型、控制方法及特点作了论述。     

并联式轴用压电六维力/力矩传感器

针对巨型重载操作装备极端制造中多维大载荷测量的难题,提出一种利用压电石英作为力敏元件的新型并联式轴用压电六维力/力矩传感器。对比各种力敏元件的性能,选择压电石英作为力敏元件可以实现空间力/力矩的动态测量,分析压电石英晶组不同空间布局方式的测量原理,提出并联式轴用压电六维力/力矩传感器的多点测量原理,分别对其建立空间力学模型,并进行解耦计算。设计出高灵敏度、高刚度、高线性度的非组装整体化六维力/力矩传感器新结构。研究并联式轴用压电六维力/力矩传感器的标定方法,并进行静态和动态标定试验,得到六维力/力矩传感器的标定矩阵和误差矩阵。试验表明,该六维力/力矩传感器可以动态测量空间六维力/力矩,具有量程大、线性好、固有频率高、动态性能好和应用场合多等优点。     

硅基PZT压电功能结构研究

PZT压电薄（厚）膜是制备MEMS传感元件和执行元件重要的功能材料,对近年PZT薄（厚）膜在MEMS领域的研究现状进行了分析,提出了一种新型的双杯PZT/Si膜片式功能结构;采用有限元方法对双杯PZT/Si膜片进行了结构优化,得到PZT和上、下硅杯的结构优化值为DPZT: D1:D2 =0.75:1.1:1;一阶模态谐振频率为13.2KHz;以氧化、双面光刻、各向异性刻蚀,以及PZT厚膜丝网印刷等工艺技术制作了双杯硅基PZT压电厚膜膜片,该膜片具有压电驱动功能。双杯PZT/Si膜片式功能结构的MEMS技术兼容性好,对芯片内其它元件或电路的影响小,适合作为MEMS片内执行元件的驱动机构。     

Modeling and nonlinear analysis of a micro-switch under electrostatic and piezoelectric excitations with curvature and piezoelectric nonlinearities

In this paper, a comprehensive model of a micro-switch with both electrostatic and piezoelectric excitations, which accounts for the nonlinearities due to inertia, curvature, electrostatic forces and piezoelectric actuator is presented to demonstrate the mechanical characteristics of such a micro-system. Dynamic equations of this model are derived by the Lagrange method. Static analysis of this model is performed with five modes through the Galerkin method. The micro-switch beam is assumed as an elastic Euler-Bernoulli beam with clamped-free end conditions. The electrostatic actuation results are compared with other existing experimental and numerical results. Whereas the major drawback of electrostatically actuated micro-switches is the high driving voltage, using the piezoelectric actuator in these systems can provide less driving voltage and control the pull-in voltage. The study demonstrates that when the ratio of electrostatic actuation distance to length of micro-switch is small, the nonlinear piezoelectric term has a significant effect on the pull-in phenomenon. There are three ways to influence the design and control of the mechanical characteristics of this micro-switch: the softening effect due to electrostatic actuation, the hardening effect due to piezoelectric actuation, and varying the length and thickness of the piezoelectric actuator.     

Study on grinding of LiTaO3 wafer using effective cooling and electrolyte solution

As a typical multi-functional single crystal material, lithium tantalate (LiTaO₃ or LT) exhibits its excellent electro-optical, piezoelectric properties and has now been widely applied into many applications, such as electro-optical modulators, pyroelectric detectors, optical waveguide, piezoelectric transducers and SAW (surface acoustic wave) substrates. LT is known as a very important functional material, however the details of its machinability are not readily available yet. The content in this study is firstly focuses on the physical properties of LT like piezoelectric and pyroelectric effects and their influence on grinding performance. The obtained results are analyzed and discussed to understand its physical properties which have significant influences on their machinability in the grinding process. The crack initiation is possible to be dominated by internal stress which originated from self-polarization of the material itself. Hence, in order to suppress the physical effects induced by polarization during grinding of LT, control the temperature of coolant and increase the electrical conductivity of coolant are purposely tried in this study. The grinding results suggest that control of coolant temperature and use of electrolyte solution can effectively suppress the increasing rate of grinding torque and surface roughness, which in turn enhance the performance of LT wafer grinding. The LT wafers are eventually able to be thinned less than 100 μm.     

一种新型PZT压薄膜应力传感器的设计仿真

针对目前应力传感器不能兼顾柔性、动态测量及无法测量曲面接触应力特征信息等难题,设计了一种新型的PZT压电薄膜柔性应力传感器。主要有由PZT压电薄膜、导线、特殊的压敏涂层等构成。传感器的受力信息可以通过检测PZT压电薄膜传感器的电荷变化来获取,可应用于测量各种接触面之间的应力。为研究测量轮胎路面等具有复杂曲面接触结构的应力分布提供了新的思路和方法,分析了压电传式感器的工作原理,压电薄膜的传感特性,建立有限元分析模型,进行仿真分析,结果表明该传感器结构简单、体积小,相对于传统测量方法更加可靠,适用于曲面应力的测量。     

球壳与柱壳之功能梯度压电涂层的热效应分析

针对以球壳和圆柱壳为基体的功能梯度压电涂层,由多场耦合控制方程和层间连续条件导出递推关系,建立了显式的力-电-热多场耦合解。对于多层功能梯度压电涂层,此解为精确解;对于连续功能梯度压电涂层,可将涂层分为若干层,只要层数取得足够大,所得的近似解将收敛于精确解。研究表明：压电效应对基体的应力影响可以忽略,但对涂层的应力影响非常显著;增加层数并不能有效降低最大应力,但增加层数可显著减小相邻层层间周向应力的突变幅度,减小层间应力集中;然而涂层与基体之间的界面径向应力却随层数的增大而使界面强度弱化。     

TiCN涂层硬质合金刀具铣削性能研究

采用Kistler三向压电铣削测力仪测试了刀具切削45钢过程中的切削力,利用超景深显微镜、扫描电镜和能谱仪观察分析刀具切削后的磨痕宽度、形貌和成分,获得了未涂层刀具HSS、TiN和TiCN涂层刀具的切削时间与磨痕宽度关系图,探讨了刀具的切削失效机理。采用XRD分析了涂层刀具铣削前的相结构,结果表明:TiN与TiCN涂层均表现为fcc-TiN相结构,TiCN具有明显的(111)择优取向,TiN择优取向不明显。切削试验表明:在磨痕宽度达到0.3mm时,TiCN涂层刀具的切削时间比TiN涂层刀具切削时间约长2.5倍,同时整个切削过程中TiCN比TiN具有更低的切削力。这可能是因为TiCN涂层比TiN涂层具有更高的硬度和耐磨性,并且切削过程中TiCN涂层中固溶的C能析出至晶界处,起到润滑作用,降低刀具与工件材料之间的摩擦,减小切削力,延长刀具使用寿命。SEM和EDS分析表明:TiN涂层刀具磨损失效机理为磨料磨损和粘着磨损,而TiCN涂层刀具失效以磨料磨损为主。     

高效感应重熔自动化设备的研制与应用

为了解决传统涂层制备工艺不能兼顾涂层质量和生产效率的难题,基于PLC控制技术,研制了高效感应重熔自动化设备,实现了感应加热温度的自动化控制及感应重熔的高效化。利用该自动化设备制备了镍基感应重熔涂层,分别与采用火焰喷焊、等离子喷焊技术制备的涂层进行了微观组织、显微硬度对比分析,并对三种制备工艺的经济性及生产效率进行了对比分析。结果表明,与火焰喷焊涂层和等离子喷焊涂层相比,感应重熔涂层的微观组织更加致密细腻、孔隙率较小、显微硬度较高;其直接生产成本仅为火焰喷焊、等离子喷焊的30.6%、46.3%,而生产效率远高于其他两种工艺。因此,设计的高效感应重熔自动化设备不仅能够保障涂层质量,而且具有较高的生产效率和较好的经济性。     

PZT薄膜驱动的全光纤相位调制器数学模型

提出了一种简单、高效的PZT压电陶瓷薄膜覆膜驱动的全光纤相位调制器数学模型,该模型计入了PZT压电陶瓷薄膜侧向压电常数d₃₁对相位调制效率的影响,结果表明,对于PZT压电陶瓷薄膜覆膜驱动的全光纤相位调制器,这种影响是不能忽略的,由侧向压电常数d₃₁引起的相位调制相当于由压电常数d₃₃引起的相位调制的15%。应用此模型计算了PZT压电陶瓷薄膜、内电极以及外电极的机械与压电性能等参数对于全光纤相位器的相位调制效率的影响。该模型可应用于全光纤相位调制器的设计与优化。     

ZnO镀膜光纤传感器压电层反射系数

介绍了ZnO镀膜光纤的几何结构,分析了此几何结构压电声光振荡的基本原理,给出了ZnO镀膜光纤传感器的等效网络模型,根据此模型推出了压电层反射系数S11,并按实际参数进行了计算机模拟计算。     

c-BN涂层及其在刀具上的应用

介绍了c BN的性能和制备c BN涂层的方法 (等离子体增强脉冲激光沉积法和热丝辅助射频等离子体CVD法 ) ;简述了c BN涂层的研究现状及其发展前景 ;通过等离子体增强脉冲激光沉积法制备c BN涂层的试验结果 ,认为增强c BN涂层与刀具基体的结合力是将c BN涂层用作刀具涂层必须解决的问题     

High temperature friction and wear characteristics of various coating materials for steam valve spindle application

Various coatings such as chromium carbide (deposited by plasma spraying and detonation gun techniques), chromium oxide, chromium oxide+titania+silica, NiCrAlY, and Al₂O₃+NiAl, all deposited by plasma spraying; stelliting, and surface nitriding have been applied on X20CrMo V121 steel. This steel is used for high temperature applications such as steam turbine valve spindle. Friction and wear behavior of the surface coated and treated materials have been studied at an elevated temperature of 550°C while rubbing against graphite-filled stellited steel. These studies have been carried out on SRV Optimol reciprocating tribometer. Test parameters for tribological studies have been selected with a view to simulate operating conditions encountered in operation. Additionally, the structure, porosity, hardness, bond strength, and thermal cycling behaviour of these surface coated/treated materials have been characterised. Based on these laboratory investigations, chromium carbide coating deposited by plasma spraying technique has been identified as the most suitable coating for steam turbine valve spindle application. Process parameters have been established for deposition of chromium carbide coating by plasma spraying technique on actual valve spindles. The field results obtained are found to be commensurate with the laboratory findings.