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91.
采用压电分流阻尼原理,对根部粘贴压电陶瓷片的柔性悬臂梁振动控制进行了实验研究。实验中设计了一个由电容、电阻和运算放大器组成的等效电感电路,解决了压电分流电路设计中的超大电感器问题。根据测试得到的带压电分流电路悬臂梁的闭路和开路自然频率,确定出了压电分流电路的最优参数,对悬臂梁的瞬态振动和单频简谐激励下的稳态振动控制实验表明了压电分流阻尼被动控制结构振动的有效性。 相似文献
92.
Lee Jae-Kon 《Journal of Mechanical Science and Technology》2005,19(11):2025-2031
Eshelby type micromechanics model with a newly developed piezoelectric Eshelby tensor is proposed for predicting the effective
electroelastic properties of the piezoelectric composite. The model is applied for piezoelectric solids containing both porosities
and metal inhomogeneities. The effective electroelastic moduli of the composites such as stiffness, piezoelectric constants,
and dielectric constants are predicted by the present model, which are extensively compared with the existing experimental
results from the literatures. The validity of Eshelby type model for predicting the effective properties of the composite
is thoroughly examined. It can be concluded from this study that a new mechanism is needed to compute correctly the dielectric
constants among the effective properties of the composites. 相似文献
93.
Man-Soon Yoon Neamul Hayet Khansur Byung-Ki Choi Young-Geun Lee Soon-Chul Ur 《Ceramics International》2009,35(8):3027-3036
(Bi0.5Na0.5)0.94Ba0.06TiO3 (abbreviated as BNBT6) ceramic of near MPB composition was synthesized by two different processes. The first one is the addition of pre-synthesized BaTiO3 and pre-milled Bi2O3, Na2CO3, BaCO3 powders and calcination powder milled with a high energy milling machine in order to obtain a nano-particle size. The second one is a conventional one to compare with the former process. The pre-milling and the pre-synthesis process of raw materials lowered the calcination temperature to the extent of 59 °C as compared with conventionally fabricated BNBT6. The particle size of the powder exposed to heavy high energy milling reduced to 50–70 nm, whereas that of the conventionally ball-milled powder without the pre-milling and the pre-synthesis process had a larger size of 280 nm. To investigate the effects of the modified process on the characteristic of BNBT6 ceramics, the dielectric and the piezoelectric properties of sintered specimens fabricated by the two different processes were evaluated. It was found that the properties of the nano-sized BNBT6 ceramic near the MPB composition were increased by the modified mixing and milling method, showing superior characteristics in terms of the piezoelectric/dielectric constant and sintering density compared with those of the conventional process. The modified mixing and milling method was considered to be a new and promising process for lead-free piezoelectric ceramics owing to their excellent piezoelectric/dielectric properties. 相似文献
94.
Nd2O3 doped 0.82Bi0.5Na0.5TiO3–0.18Bi0.5K0.5TiO3 (abbreviated to BNKT) binary lead-free piezoelectric ceramics were synthesized by the conventional mixed-oxide method. The results show that the BNKT ceramics with 0–0.15 wt.% Nd2O3 doping possesses a single perovskite phase with rhombohedral structure. The grain size of BNKT decreased with the addition of Nd2O3 dopant. The temperature dependence of the dielectric constant ?r revealed that there were two-phase transitions from ferroelectric to anti-ferroelectric and anti-ferroelectric to paraelectric. A diffuse character was proved by linear fitting of the modified Curie–Weiss law. At room temperature, the specimens containing 0.0125 wt.% Nd2O3 with homogeneous microstructure presented excellent electrical properties: the piezoelectric constant d33 = 134 pC/N, the electromechanical coupling factor Kp = 0.27, and the dielectric constant ?r = 925 (1 kHz). 相似文献
95.
针对目前航空工业对高频响、高精度的射流管伺服阀需求,设计了一款压电叠堆驱动式射流管伺服阀,分析了其工作原理,研究了伺服阀的射流区及滑阀的特性,建立了其动力学模型,并通过仿真试验将其与传统的电磁式射流管伺服阀进行了对比分析。仿真试验结果表明:该型压电叠堆驱动式射流管伺服阀与电磁式射流管伺服阀相比,响应速度提升0.8 ms、频响提升5倍、稳定性好、控制精度高,且能达到需求的滑阀位移。该压电式射流管伺服阀的设计为改进传统的射流管伺服阀提供了一种新的方法。 相似文献
96.
97.
A. Ngamjarurojana S. Ural S.H. Park S. Ananta R. Yimnirun K. Uchino 《Ceramics International》2008,34(4):705-708
In this study, in order to develop low-temperature sintering ceramics for a multilayer piezoelectric transformer application, we explored CuO and Bi2O3 as sintering aids at low temperature (900 °C) sintering condition for Sb, Li and Mn-substituted 0.8Pb(Zr0.48Ti0.52)O3–0.16Pb(Zn1/3Nb2/3)O3–0.04Pb(Ni1/3Nb2/3)O3 ceramics. These substituted ceramics have excellent piezoelectric and dielectric properties such as d33 347 pC/N, kp 0.57 and Qm 1469 when sintered at 1200 °C. The addition of CuO decreased the sintering temperature through the formation of a liquid phase. However, the piezoelectric properties of the CuO-added ceramics sintered below 900 °C were lower than the desired values. The additional Bi2O3 resulted in a significant improvement in the piezoelectric properties. The composition Sb, Li and Mn-substituted 0.8Pb(Zr0.48Ti0.52)O3–0.16Pb(Zn1/3Nb2/3)O3–0.04Pb(Ni1/3Nb2/3)O3 + 0.5 wt% CuO + 0.5 wt% Bi2O3 showed the value of kp = 0.56, Qm = 1042 (planar mode), d33 = 350 pC/N, when it was sintered at 900 °C for 2 h. These values indicated that the newly developed composition might be suitable for multilayer piezoelectric transformer application. 相似文献
98.
99.
Shinya Inai Yuji Hiruma Muneyasu Suzuki Hajime Nagata Tadashi Takenaka 《Ceramics International》2008,34(4):741-744
The temperature dependence of the piezoelectric properties of vanadium substituted strontium bismuth niobate, SrBi2Nb1.95V0.05O9 (SBNV) ceramics, were investigated in various vibration modes. The effects of grain orientation in SBNV ceramics on the piezoelectric properties were also studied by the hot-forging (HF) method. The anisotropy of the piezoelectric properties of each vibration mode was confirmed by observing the grain orientation. In particular, HF-SBNV ceramics of the (33) and (15) modes showed excellent piezoelectric properties with relatively high mechanical quality factors, Qm (2200, 4600), and high electrical quality factors, Qe max (66.0, 21.6), respectively. In addition, HF-SBNV ceramics showed low temperature coefficients of resonance frequency TC-fr (−16.5, −27.0). HF-SBNV ceramics are considered to be superior candidates for the lead-free piezoelectric application of ceramic resonators. 相似文献
100.
Commercial lead zirconate titanate (PZT) perovskite powders were used to fabricate ceramic tape and then sintered by microwave and conventional methods. Both dielectric and piezoelectric properties of PZT ceramic tapes were studied in terms of sintering process. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) show the PZT perovskite phase with smaller grain size and dense microstructure can be obtained at a lower sintering temperature by microwave process. It was also observed that shrinkage ratio and bulk density of the tapes sintered at 800 °C were obtained about 19% and 7.46 g/cm3 by the microwave heating method, respectively, that is corresponding to those values of sintered PZT tapes at 950 °C by conventional process. Moreover, the dielectric constant and maximum permittivity are increased about 30% as compared with conventional processing method. The experimental results demonstrated that the characteristics of the PZT tapes could be significantly improved by microwave heating method. These results demonstrate that such a simple approach can upswing the piezoelectric and dielectric properties of these tapes by using microwave process with a short heating time. 相似文献