scholarly journals Onset and stabilization of delay-induced instabilities in piezoelectric digital vibration absorbers

Author(s):  
Ghislain Raze ◽  
Jennifer Dietrich ◽  
Gaetan Kerschen

The stability of a piezoelectric structure controlled by a digital vibration absorber emulating a shunt circuit is investigated in this work. The formalism of feedback control theory is used to demonstrate that systems with a low electromechanical coupling are prone to delay-induced instabilities entailed by the sampling procedure of the digital unit. An explicit relation is derived between the effective electromechanical coupling factor and the maximum sampling period guaranteeing a stable controlled system. Since this sampling period may be impractically small, a simple modification procedure of the emulated admittance of the shunt circuit is proposed in order to counteract the effect of delays by anticipation. The theoretical developments are experimentally validated on a clamped-free piezoelectric beam.

1997 ◽  
Vol 12 (1) ◽  
pp. 226-234 ◽  
Author(s):  
Q. M. Zhang ◽  
Jianzhong Zhao ◽  
K. Uchino ◽  
Jiehui Zheng

The properties of several Pb(ZrTi)O3 (PZT) piezoceramics under compressive uniaxial stresses were characterized. It was observed that uniaxial stresses have a marked effect on the soft PZT materials, including reducing the piezoelectric coefficients and depoling the samples at relatively low stress levels. The effect of the uniaxial stresses on the properties of hard PZT's is more complicated because the domain structure of the materials can be changed substantially without depoling the samples. Therefore, under a compressive stress along the poling direction, the piezoelectric and electromechanical coupling factor can be increased markedly due to both the increased non-180° domain boundary motions and the deaging effect. In addition, the experimental results support the notion that the difference between a hard PZT and a soft PZT lies in the types of defects introduced by dopants. Immobile defects create frustrations in the lattice and result in a soft behavior, and mobile defects stabilize the polarization and produce a hard behavior.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 549-556
Author(s):  
Yajun Luo ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
Xinong Zhang

The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance.


Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6438
Author(s):  
Guangtao Lu ◽  
Xin Zhu ◽  
Tao Wang ◽  
Zhiqiang Hao ◽  
Bohai Tan

A novel piezoceramic stack-based smart aggregate (PiSSA) with piezoceramic wafers in series or parallel connection is developed to increase the efficiency and output performance over the conventional smart aggregate with only one piezoelectric patch. Due to the improvement, PiSSA is suitable for situations where the stress waves easily attenuate. In PiSSA, the piezoelectric wafers are electrically connected in series or parallel, and three types of piezoelectric wafers with different electrode patterns are designed for easy connection. Based on the theory of piezo-elasticity, a simplified one-dimensional model is derived to study the electromechanical, transmitting and sensing performance of PiSSAs with the wafers in series and parallel connection, and the model was verified by experiments. The theoretical results reveal that the first resonance frequency of PiSSAs in series and parallel decreases as the number or thickness of the PZT wafers increases, and the first electromechanical coupling factor increases firstly and then decrease gradually as the number or thickness increases. The results also show that both the first resonance frequency and the first electromechanical coupling factor of PiSSA in series and parallel change no more than 0.87% as the Young’s modulus of the epoxy increases from 0.5 to 1.5 times 3.2 GPa, which is helpful for the fabrication of PiSSAs. In addition, the displacement output of PiSSAs in parallel is about 2.18–22.49 times that in series at 1–50 kHz, while the voltage output of PiSSAs in parallel is much less than that in parallel, which indicates that PiSSA in parallel is much more suitable for working as an actuator to excite stress waves and PiSSA in series is suitable for working as a sensor to detect the waves. All the results demonstrate that the connecting type, number and thickness of the PZT wafers should be carefully selected to increase the efficiency and output of PiSSA actuators and sensors. This study contributes to providing a method to investigate the characteristics and optimize the structural parameters of the proposed PiSSAs.


2001 ◽  
Vol 687 ◽  
Author(s):  
Jürgen Brünahl ◽  
Alex M. Grishin ◽  
Sergey I. Khartsev ◽  
Carl Österberg

AbstractWe report on comprehensive characterization of piezoelectric shear mode inkjet actuators micromachined into bulk Pb(Zr0.53Ti0.47)O3 (PZT) ceramics. The paper starts with an overview of different inkjet technologies such as continuous jet and drop-on-demand systems, whereat main attention is turned on piezoelectric systems particularly Xaar-type shear mode inkjet color printheads. They are an example of complex microelectromechanical systems (MEMS) and comprise a ferroelectric array of 128 active ink channels (75νm wide and 360νm deep). Detailed information about manufacturing and principles of operation are given. Several techniques to control manufacturing processes and to characterize properties of the piezoelectric material are described: dielectric spectroscopy to measure dielectric permittivity ε and loss tanσ; ferroelectric hysteresis P-E loop tracing to get remnant polarization Pr and coercive field Ec, and a novel pulsed technique to quantify functional properties of the PZT actuator such as acoustic resonant frequencies and electromechanical coupling factor. Stroboscope technique has been employed to find correlation between the degradation of ink-jet performance and heat/high voltage treatment resulting in ferroelectric fatigue.


2006 ◽  
Vol 45 ◽  
pp. 2412-2421
Author(s):  
Toshio Ogawa

Giant electromechanical coupling factor of k31 mode over 86% was found for (100) Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 and (110) Pb[(Mg1/3Nb2/3)0.74Ti0.26]O3 single-crystal plates poled in the [100] and [110] directions, respectively. The P-E hysteresis loops in the single-crystal plates with giant k31 became asymmetric. Furthermore, the frequency response of impedance in these plates with giant k31 consisted of a single vibration in the length direction. A mechanism to realize giant k31 can be explained by the relationship between the crystal plane and poling direction. In addition, the existence of giant piezoelectric d31 constant was proven by the strain measurement as well as by the impedance measurement.


2015 ◽  
Vol 08 (05) ◽  
pp. 1550049 ◽  
Author(s):  
Vitaly Yu. Topolov ◽  
Christopher R. Bowen ◽  
Paolo Bisegna ◽  
Anatoly E. Panich

The influence of the aspect ratio and volume fraction of ferroelectric ceramic inclusions in a 0–3 matrix on the hydrostatic parameters of a three-component 1–3-type composite is studied to demonstrate the important role of the elastic properties of the two-component matrix on the composite performance. Differences in the elastic properties of the 0–3 matrix and single-crystal rods lead to a considerable dependence of the hydrostatic response of the composite on the anisotropy of the matrix elastic properties. The performance of a 1–0–3 0.92 Pb ( Zn 1/3 Nb 2/3) O 3–0.08 PbTiO 3 SC/modified PbTiO 3 ceramic/polyurethane composite suggests that this composite system is of interest for hydroacoustic applications due to its high hydrostatic piezoelectric coefficients [Formula: see text] and [Formula: see text], squared figure of merit [Formula: see text], and electromechanical coupling factor [Formula: see text].


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