Calculating impedance vibrator antennas

The technique of analytical reversal of a hypersingular equation is used to solve the equation of an impedance vibrator antenna. A numerical method for solving the equation is developed, and its efficiency is demonstrated.     

Diaphragm vibrator test rack

Conclusions The above diaphragm-type vibrators provide sinusoidal vibrations at an amplitudea of 2000–3000 g at four fixed frequencies in the range of 1.5–4.0 kc, with a load not exceeding 100–200 g.     

A tubular piezoelectric vibrator gyroscope

This paper proposes a vibrator gyroscope made of a piezoelectric tube, which has the same configuration as that used for the tri-axial sensors and actuators developed in our previous paper. The gyroscopic operation is the same as a circular rod, but the polarization (in thickness direction of the shell) and, accordingly, the electrode arrangement are much simpler. Wireless LAN arrangement is devised for remote data access with which the measurement is possible for the gyroscope under rotation. The experimental results are compared with the numerical simulation with three-dimensional finite-element calculation. The discrepancy between the measured and the experimental is found to depend on the asymmetrical deformation of the structure, and the cause is clearly demonstrated via simulation. This shows the usefulness of the numerical modeling to investigate the cause, in which the parameters of dimensions and boundary conditions can easily change.     

Certification of an infralow-frequency vibrator

Measurement Techniques -     

Finite element simulation of piezoelectric vibrator gyroscopes

A finite element approach to the simulation of piezoelectric vibrator gyroscopes is presented for characteristic prediction. The formulation is given including the effect of Coriolis force due to rotation for a piezoelectric thin plate, which is considered to be two-dimensional in plane vibration. For numerical examples, the gyroscopes of a thin square plate, and a cross-bar and a ring built in the plate are considered, which pave the way for the development of the gyroscopes of monolithic configuration. The effect of the rotation on the modal shapes, the resonant frequencies, and the transmission characteristics are discussed demonstrating the sensing capability against the rotation     

一种大功率超声振动子的实验研究

本文给出了一种大功率超声振动子的基本结构,从波动方程出发推导了各分段的位移及应变的表达式,同时给出了频率方程。采用微机辅助设计可计算出各点的位移值,应变值和尺寸。在研制过程中作者对国内传统的结构设计和装配工作作了较大的改进,理论值和实测值非常接近。本文所述振动子完全可以代替进口振动子,某些性能指标还超过进口同类产品。     

Portable vibrator for combined testing of instruments and sensors

A small vibrator for combined testing of instruments and sensors is developed on the basis of an inverse piezoelectric effect. The vibrator is a resonant converter with fluctuations in bending that includes a dismountable support bracket for fastening an instrument under test and a built-in piezoaccelerometer for automatic vibration control. __________ Translated from Izmeritel’naya Tekhnika, No. 4. pp. 39–43, April, 2008.     

超磁致伸缩振动器谐振频率自感知机理研究

振动系统工作在谐振频率处则其工作效率最高,但由于受到负载、温度等因素的影响,其谐振频率往往会发生漂移,为了实现对振动系统工作频率的自动调节,提高系统的工作效率,提出采用搜索振动系统速度阻抗的方法,在无需安装检测谐振频率传感器的条件下,实现振动系统谐振工作点的自感知,并能快速、方便地自动跟踪系统的谐振频率。设计了超磁致伸缩振动器,并给出了振动器机械阻抗的表达式;在分析超磁致伸缩材料磁-机耦合关系的基础上,建立了超磁致伸缩振动系统的速度、阻抗及所受外力的自感知模型;在研制的实验系统上,验证了振动系统谐振频率自感知方法的可行性与正确性。     

基于有限元法的管形振子声场特性研究

利用有限元分析软件ANSYS,对管形振子的振动模态及在清洗槽中的辐射声场进行数值计算分析,并用铝箔腐蚀的方法记录了管形振子的声场分布情况。结果表明基于线性理论的ANSYS软件能够较好地预测低强度的超声场;管形振子在清洗槽中的辐射声场在径向方向出现驻波,驻波沿管形振子的轴向间断出现,驻波数等于振子的半波长数,此外作耦合振动的管形振子和非耦合振动的振子相比其辐射的声场更均匀,表明这种新型辐射器有很好的应用前景。     

纵径耦合振动管形振子的特性研究

对纵径耦合振动的管形振子进行了研究,给出了管形振子的频率方程,并利用有限元和边界元软件对管形振子的振动模态和辐射的声场特性进行了分析。对于管形振子,由于振子各部分的振动幅度和相位不同,因而在振子径向位移较大的水平区域声场加强,较小的水平区域声场减弱。通过实验验证了分析结果的正确性。     

旋转式惯性压电电机的振子模型研究

提出了一种新型旋转式压电惯性电机,利用压电双晶片振子作为驱动元件,用锯齿波作为激励电信号产生惯性冲击力使电机旋转。分析了旋转式压电惯性电机的驱动机理,建立了压电振子的动力学模型,求解了振子的自由振动固有频率和模态函数。分析了影响压电振子固有频率的系统参数及其影响规律。计算结果表明梁端部模态函数值与质量系数α的值成反比。这些结论为压电惯性电机的设计和进一步的研究提出了新的思路和方法。     

A functional for the input impedance of thin electric vibrator

A functional for the input impedance of electric vibrator is derived for the variation of the distribution of vibrator current. Using the approximation of sinusoidal current distribution, a simple approximate formula for the input impedance of a symmetric electric vibrator is derived. The active and reactive components of impedance are calculated versus the ratio of the length of vibrator arm to wavelength for three values of the vibrator diameter.     

Three-dimensional finite element simulation of a piezoelectric vibrator under gyration

A three-dimensional finite element modeling is applied to the characteristic evaluation of the piezoelectric gyroscopes. The Coriolis' effect is incorporated with the three-dimensional finite element code that we have already developed. There is no limitation for the vibrational modes and the direction of the gyratory axis. The piezoelectric thin plate gyroscope in plane vibration is again considered for the demonstration. The solution characteristics are compared with those of the two-dimensional modeling and also with the experimental results. Reasonable agreement is achieved. The application is then extended to a bimorph-type gyroscope vibrating out of plane, which is only numerically considered for another example of demonstration. The examination shows that, with this configuration, not only the rotation but also the gyratory axis can be detected in the three-dimensional space     

Fe-Ga合金发音振子换能器的多场耦合模型

建立了Fe-Ga合金弓张结构发音振子换能器电场、磁场和固体力学场的多场耦合模型,研究了发音振子换能器磁场强度、磁感应强度和应变分布情况,并进行了换能器在不同频率下的磁场强度分析和模态分析。分析发现,随着频率的增高,Fe-Ga合金发音振子换能器的磁场强度逐渐减小,计算得到换能器的共振频率为984 Hz。测试了Fe-Ga合金换能器中的核心元件Fe-Ga合金的磁场强度与应变的关系,当磁场强度饱和值为40 k A·m-1时,应变为70×10-6。搭建了磁致伸缩材料磁特性测试系统,测试了Fe-Ga合金磁场频率为5、20、50 Hz的磁滞曲线,并测试了Fe-Ga合金的应变随频率的变化曲线,实验结果与换能器中Fe-Ga合金的应变仿真结果一致。     

声桥系统压电植入振子力学建模及参数优化

根据作用于圆窗的压电式振动声桥的工作原理,建立了压电振子与圆窗耦合的动力学模型,由此推导出该模型的电-机能量转化的传递函数.通过在Matlab环境中进行仿真试验,讨论了压电应变常数、振子支座质量及支座刚度等参数对传递函数的影响,并分别优化了各个参数.研究结果为新型振动压电植入振子的研制奠定了理论基础.     

震源振动器平板损伤机理及其疲劳寿命预测研究

振动器是可控震源地震信号激发的关键装置,长期宽、高频地震波激发致使振动器平板焊接部位出现裂纹甚至疲劳失效,这不仅会大大减短平板工作寿命,而且严重影响震源信号质量。由此,对平板开裂断口的微观形貌进行分析,掌握平板疲劳损伤区域内损伤特征、裂纹扩展规律,揭示平板开裂断口损伤机理。针对平板疲劳损伤模式和特点,开展平板“三点弯曲”疲劳试验,拟合平板S—N曲线,预测平板疲劳寿命,并与采用断裂力学法的疲劳寿命计算结果进行比较。结果表明,经疲劳试验参数修正的S—N曲线法的精度高于断裂力学法,可准确预测震源振动器平板的工作寿命。研究成果为延长震源振动器平板的疲劳寿命、增强其可靠性提供了科学的理论支持,有助于提高我国油气勘探技术及相关工程装备的研发水平和国际竞争力。