Multilayer Piezoelectric Actuator Research Articles

Effects of Strain Node on the Actuation Performance of Multilayer Cantilevered Piezoactuator with Segmented Electrodes

A model of a segmented electrode multilayer cantilever piezoelectric actuator was established to predict its actuation performance, and then, theoretical and numerical analyses of the strain nodes were performed based on normalized deflection and strain distributions. The segmented electrodes instead of the continuous electrodes are applied in a multilayer cantilever piezoelectric actuator which can avoid the modal displacement offsets at the high vibration modes, thereby enhancing the tip deflection. The theoretical analysis and simulation results show that the tip deflection of the segmented electrode at the second mode was almost 100% larger than that of the continuous electrode. At the second mode, the maximum error between the theoretical calculation value of the tip deflection and the simulation result is 6.8%. It is because the segmented electrode is optimally designed at the strain node, which avoids the modal displacement offsets of a multilayer cantilever piezoelectric actuator at the high vibration modes; meanwhile, the theoretical results are closer to the FEM simulation results. It reveals that the tip deflection of a multilayer cantilever piezoelectric actuator can be precisely estimated by the proposed model. This research can provide some useful guidance improving the actuation performance and optimizing the design of a multilayer cantilever piezoelectric actuator.

FEM implementation of the nonlinear damage evolution model for piezoelectric material under bipolar electrical fatigue load

The service life of piezoelectric actuator is significantly affected by the high electric fatigue load. Predicting damage evolution in piezoelectric materials under high electric load is essential for the reliability and life prediction of piezoelectric structures and devices. In this paper, a nonlinear damage evolution FE model and its acceleration program are proposed which are capable of modeling nonlinear damage evolution of piezoelectric material and structure under high electric fatigue load. The simulation results of degraded piezoelectric constant varying with the number of cycles are compared with the experimental results, and a well agreement verifies the validity of the nonlinear damage evolution FE model. Moreover, the damage distribution evolution of piezoelectric multi-layer actuator with standard double comb electrode is studied by the proposed nonlinear damage evolution model. The driving performance of piezoelectric multi-layer actuator decreases rapidly under the high electric fatigue load, where the damage area starts from the tip of the electrode and gradually spreads to the area between the electrodes. Based on the nonlinear damage evolution and its FEM implementation, the damage distribution and evolution for piezoelectric structures with variable amplitude bipolar electrical fatigue load can be obtained. This provides a reliable reference for the life prediction and application of the piezoelectric actuator.

Study on Multidegree-of-Freedom Ultrasonic Motor Using Vibration Mode Rotation of Metal Spherical Stator

Most of the multidegree-of-freedom ultrasonic motors (MDOF-USMs) use a spherical rotor, and the design of the stator is restricted due to the use of the resonance mode. (1) Therefore, there is almost impossible to freely design the overall shape, resulting in a complicated structure. (2) To solve such an inconvenience, an MDOF-USM using a metal spherical stator was proposed. The vibration mode rotation on the stator was designed by theoretical analysis of spherical vibration and finite element method analysis. Multilayer piezoelectric actuators (MPAs) were embedded in the sphere to excite the vibration mode. Cylindrical projections were attached to the surface of the stator to magnify the vibration displacement and worked as the driving part. Their effects were evaluated using an electronic circuit simulator method of performance analysis. (3) As a result, two types of vibration mode rotation methods for the 3-DOF rotation were confirmed. It was also confirmed that the rotor covering the outside stator rotates around three axes. However, tiny torque, low power factor, and slow speed were obtained. (4) An MDOF-USM using a spherical stator was realized according to the operating principle. However, since the cause of such a low performance is the excitation method of the sphere and the rotor structure, research for improvement is required in the future.

Design and Development of Outstanding Strain Properties in NBT-Based Lead-Free Piezoelectric Multilayer Actuators by Grain-Orientation Engineering

Design and Development of Outstanding Strain Properties in NBT-Based Lead-Free Piezoelectric Multilayer Actuators by Grain-Orientation Engineering

Application of Multilayer Piezoelectric Actuator in Lithography Scanners

Application of Multilayer Piezoelectric Actuator in Lithography Scanners

Piezoelectric Ceramics with High d33 Constants and Their Application to Film Speakers.

A multilayer piezoelectric material was fabricated using piezoelectric materials with low-temperature sintering capabilities and high piezoelectric coefficients to develop a functionally superior piezoelectric speaker with a large-displacement deformation. A soft relaxor was utilized to prepare the component materials, with the optimized composition of the investigated piezoelectric ceramics represented by . was added to assist the low-temperature sintering conducted at 875 °C, which yielded a multilayer piezoelectric material with superior properties (= 500 pC N−1, = 0.63, = 44 mV N−1). A multilayer piezoelectric actuator with a single-layer thickness of ~40 µm and dimensions of 12 × 16 mm2 was fabricated by tape casting the prepared green sheets. Finite element analysis revealed that the use of a PEEK film and a smaller silicone–rubber film as a composite in the diaphragm realized optimal frequency-response characteristics; the vibrations generated by the piezoelectric element were amplified. The optimal structure obtained via simulations was applied to fabricate an actual piezoelectric speaker with dimensions of 20 × 24 × 1 mm3. The actual measurements exhibited a sound pressure level of ~75 dB and a total harmonic distortion ≤15% in the audible frequency range (250–20,000 Hz) at an applied voltage of 5.

Low temperature sintering of Li2CO3 added Pb(Ni1/3Nb2/3)-Pb(Zr,Ti)O3 ceramics with high piezoelectric properties

Multilayer structure is an effective approach for reducing driving voltages or increasing output electric signal for piezoelectric devices. However, it is a challenge to achieve high piezoelectric coefficient at low sintering temperature. In this work, we fabricated Li2CO3 (LC) doped Pb(Ni1/3Nb2/3)-Pb(Zr,Ti)O3 (PNN-PZT) ceramics via solid state reaction method. Piezoelectric coefficient at low quasi-static signal d33 and effective piezoelectric coefficient under high electric field d33* are 692 pC/N, 1114 pm/V for PNN-PZT+0.2 wt% LC sintered at 950 °C, which is comparable to high temperature sintered commercial Pb(Zr,Ti)O3 (PZT) based ceramics. Detailed piezoelectric, ferroelectric, dielectric properties, temperature stability and material structure were investigated. The planar electromechanical coupling factor Kp, relative dielectric constant εr and dielectric loss tan δ at 1 kHz, Curie temperature Tc, coercive electric field Ec are measured to be 0.557, 4280, 0.025, 113 °C, 4.34 kV/cm. It shows great potential for applications in multilayer structured cofired piezoelectric actuators and transducers.

Low sintering temperature, large strain and reduced strain hysteresis of BiFeO3–BaTiO3 ceramics for piezoelectric multilayer actuator applications

BiFeO3–BaTiO3 solid solutions with pseudo-cubic phase have received a lot of attention because of their large strain for potential piezoelectric multilayer actuator applications. However, the high sintering temperature, large dielectric loss and severe strain hysteresis hindered their real applications. In this work, Li2CO3 sintering aid modified 0.64BiFeO3-0.36BaTiO3 (BF-BT-L) ceramics were prepared by the high-temperature sintering method, and their phase structure, microstructure, electric properties as well as strain were investigated. With the increase of Li2CO3 content, the sintering temperature decreases down to 900 °C, and the relative density increases up to 96%. Of particular importance is that the dielectric loss and strain hysteresis of BF-BT-L ceramics are reduced by 40% and 47%, respectively, while BF-BT-L ceramics shows a large strain of 0.3% (60 kV/cm). The sintering temperature, relative density, strain, large-signal d33* and strain hysteresis of BF-BT-L ceramics are 900 °C, 96.5%, 0.3%, 500 pm/V, and 25% respectively. The reduced dielectric loss and strain hysteresis result from the enhanced relative density, decreased concentration of defects and partial phase transition from partial pseudo-cubic to rhombohedral one by Li2CO3 additions. Furthermore, BF-BT-L ceramics show positive temperature dependent strain, with large d33* and strain hysteresis of 675 pm/V and 15% at 200 °C respectively. The simple composition, low sintering temperature, large strain and reduced strain hysteresis of BF-BT-L ceramics indicate that they are promising candidates for high-performance and lead-free piezoelectric multilayer actuator applications.

Simultaneously improving piezoelectric properties and temperature stability of Na0.5K0.5NbO3 (KNN)-based ceramics sintered in reducing atmosphere

It is a very difficult work to sinter K0.5Na0.5NbO3 (KNN)-based materials with good reduction resistance in strong reducing atmosphere. 0.945K0.48Na0.52Nb0.96Ta0.04O3−0.055BaZrO3 + 0.03ZrO2 + y mol%MnO (KNNT−0.055BZ + 0.03Zr + yMn) ceramics sintered in reducing atmosphere were prepared successfully by conventional solid-state reaction methods. MnO dopant increases grain size at y = 5–8 due to strong lattice distortion and then decreases grain size at y = 9 due to much Mn4Nb2O9 accumulated at the grain boundary. MnO dopant as an excellent sintering aid can effectively reduce volatilization of alkali metal by decreasing the sintering temperature (Tsinter). Reducing alkali metal volatilization can greatly reduce oxygen vacancies and improve piezoelectric properties. MnO dopant can improve the anti-reduction properties. The KNNT−0.055BZ + 0.03Zr + yMn ceramics at y = 6–9 show outstanding anti-fatigue of unipolar piezoelectric strain under the synergistic effect of reduced oxygen vacancies due to reduced volatilization and increased grain size. Piezoelectric properties and temperature stability of KNNT−0.055BZ + 0.03Zr ceramics sintered in reducing atmosphere are improved simultaneously by MnO dopant. Optimum inverse piezoelectric coefficient (d33*) of ceramics at y = 8 reaches up to 480 pm/V under low driving electric field E = 20 kV/cm at room temperature, and its temperature stability of d33* reaches 158 °C. It will be an excellent lead-free material candidate for the preparation of multilayer piezoelectric actuators co-fired with nickel electrode.

Theoretical Modeling of Piezoelectric Cantilever MEMS Loudspeakers

Piezoelectric microelectromechanical system (MEMS) loudspeakers have received extensive attention in recent years. In particular, the piezoelectric cantilever MEMS loudspeaker, which uses multilayer piezoelectric cantilever actuators (MPCAs), has attracted attention because of its small size, low cost, ease of manufacture, and desirable piston movement. However, owing to the complex driving principles of MPCAs, no adequately efficient and appropriate method currently exists that can be used to analyze and predict the performance of piezoelectric cantilever MEMS loudspeakers. In this study, the equivalent circuit method (ECM) is adopted to theoretically model piezoelectric cantilever MEMS loudspeakers, and an ECM model with a special MPCA transformer for electromechanical conversion is proposed. With the proposed ECM model, the performance characteristics of piezoelectric cantilever MEMS loudspeakers, such as the displacement and sound pressure response, can be calculated efficiently and conveniently. To verify the accuracy of the ECM model, the finite element method is adopted for simulation, and the simulated results are compared with those of the ECM models. A satisfactory agreement was found, which verifies the accuracy of the proposed ECM model.

Investigations on piezo actuated micro XY stage for vibration-assisted micro milling

Vibration assisted machining is an advanced non-conventional precision machining technique aiming at improving the machining performance by superimposing a small amplitude, high-frequency vibration either on the tool or on the workpiece. This article presents the mechanical design, electromechanical simulation, and experimentation on the developed prototype of the flexural hinged micro XY stage for the vibration-assisted micro-milling system. The micro XY stage comprises three layers of flexural hinge structure surrounding the central parallel kinematic structure. The finite element analysis method is adopted to evaluate the static structural stiffness and harmonic behaviour. Two multilayer piezoelectric stack actuators drive the micro XY stage in X and Y directions. The experimental results show that the micro XY stage has a vibrating work area of 17.06 µm × 17.11 µm with a hysteresis nonlinearity and cross-coupling displacements on both axes. Therefore, an electromechanical model is essential to compensate for the hysteresis behaviour and cross-coupling displacements. Open-loop tracking control experiments determine the accuracy of the developed electromechanical model. Implementing a combined hysteresis and cross-coupling displacement compensation approach into the electromechanical model resulted in an open-loop tracking error of 7% for the synchronised circular path and a maximum deviation of 0.6 µm from the linear path.

Rigidity of a Multilayer Piezoelectric Actuator for the Nano and Micro Range

The rigidity and elastic pliability of a multilayer piezoelectric actuator for the nano and micro range is investigated. Its mechanical and control characteristics are determined. The rigidity and elastic pliability are considered for different types of control.

The Effects of MnO2 Addition on the Physical Properties of Pb(Ni1/3Nb2/3)O3-Pb(Zr,Ti)O3-Pb(Mg1/2W1/2)O3-BiFeO3 Ceramics

In this paper, for the application to multi-layer piezoelectric devices capable of being used in piezoelectric speakers, Pb(Ni1/3Nb2/3)O3-Pb(Zr,Ti)O3-BiFeO3 ceramics substituted with Pb(Mg1/2W1/2)O3 were manufactured according to MnO2 addition, and their physical properties were studied. At non-doped MnO2 added specimen, the maximum values of piezoelectric properties were shown, respectively: the εr of 2182, d33 of 513 pC/N, and kp of 0.634. When taking into consideration the low dielectric constant and high d33 in case of increasing the numbers of multilayer in ceramics, the x = 0.2 composition ceramics was suitable for the device application such as speaker using low-temperature sintering multilayer piezoelectric actuators.

Piezoelectric Ring Bender for Characterization of Shear Waves in Compacted Sandy Soils.

Shear wave velocity and small-strain shear modulus are widely used as the mechanical properties of soil. The objective of this study is to develop a new shear wave monitoring system using a pair of piezoelectric ring benders (RBs) and to evaluate the suitability of RB in compacted soils compared with the bender element and ultrasonic transducer. The RB is a multilayered piezoelectric actuator, which can generate shear waves without disturbing soils. For five compacted soil specimens, the shear waves are monitored by using three different piezoelectric transducers. Results of time-domain response show that the output signals measured from the RB vary according to the water content of the specimen and the frequency of the input signal. Except at the water content of 9.3%, the difference in the resonant frequencies between the three transducers is not significant. The shear wave velocities for the RB are slightly greater than those for the other transducers. For the RB, the exponential relationship between the shear wave velocity and dry unit weight is better established compared with that of the other transducers. The newly proposed piezoelectric transducer RB may be useful for the evaluation of the shear wave velocity and small-strain shear modulus of compacted soils.

Electrical Properties of Force Feedback Piezoelectric Actuator Using (Na,K)(Nb,Sb)O3–(Bi,Na)ZrO3 Ceramics

In this study, for developing the multilayer piezoelectric actuator, the (Na,K)(Nb,Sb)O3–(Bi,Na)ZrO3 ceramics were manufactured and their dielectric and piezoelectric properties were investigated. The manufactured ceramics showed the excellent physical properties: density = 4.56 g/cm2, kp = 0.47, Qm = 50, er = 1944, and d33 = 313 pC/N, suitable for piezoelectric actuator. The properties of the piezoelectric actuators are as follows: at the average size of 30.47 mm $$\times$$ 17.92 mm $$\times$$ 1.0 mm, resonance frequency fr = 69.87 kHz, anti-resonance frequency fa = 71.20 kHz, kp = 0.22, d33 = 1120 pC/N were appeared, respectively. The three piezoelectric actuators connected in parallel showed the high vibration acceleration of 2.0G at 580 Hz under 70 V, suitable for the force feedback actuator.

Fabrication and performance of PNN-PZT piezoelectric ceramics obtained by low-temperature sintering

Abstract The Pb(Ni1/3Nb2/3)O3-Pb(Zr x Ti1−x )O3 (PNN-PZT) piezoelectric ceramics with CuO and LiBiO2 doping were successfully fabricated by the low-temperature solid-state reaction to effectively restrain the PbO volatilization. The microstructure and electrical properties of the PNN-PZT ceramics were characterized. The experimental results reveal that the PNN-PZT ceramics are composed of a pure perovskite structure in which the rhombohedral and tetragonal phases coexist. Meanwhile, the good electric properties, including low dielectric loss, outstanding diffusion phase transition and palpable dielectric relaxation, are exhibited in PNN-PZT ceramics with 0.2 wt.% CuO and 1 wt.% LiBiO2 addition. This piezoceramic composition possibly provides a reference for the application of multi-layer piezoelectric actuators.

Dielectric, piezoelectric and dc bias characteristics of Bi-doped PZT multilayer ceramic actuator

In this study, the microstructure, dielectric, piezoelectric and dc bias properties of the Bi-doped PZT (PZTB) multilayer piezoelectric actuators, have been discussed. The thickness of the dielectric monolayer was about 70 μm, and a relatively uniform distribution of the grain size was developed. The application of a large dc bias field resulted in a decrease in the dielectric constant and dielectric loss of the multilayer piezoelectric ceramics. The shift of the Curie temperature (Tc) towards a higher value and stabilized temperature-dependent dielectric properties were observed under the dc bias field. The increase in parameter γ suggested the enhancement of the degree of diffuseness of the phase transition. The large displacement reached 0.11% of the thickness of the multilayer piezoelectric ceramic under a low driving voltage of 150 V, indicating the potential of commercial applications of the studied multilayer piezoelectric actuators. This study provides specific experimental data to evaluate the practical application of the Bi-doped PZT multilayer piezoelectric actuators.

Displacement Analysis of a Piezoelectric Based Multi-layered Micropump Diaphragm

This paper presents the diaphragm displacement analysis of multi-layered circular piezoelectric actuator (MCPA) using analytical, numerical and experimental methods. The piezoelectric zirconate titanate (PZT) actuator model examined in this study consists of a structure with 3 different diameters and 7 layers. The multi-layered and multi-covered actuator model was composed of three main layers in different radii and thickness with silicon, brass and the PZT and four additional layers with silver and bonding. When creating an analytical model, the effects of all layers were taken into account on the static deflection performance of the actuator. The classical laminated plate theory based on Kirchhoff thin plate theory was used in the analytic modelling studies of the actuator. The mathematical model, which is the solution of the static displacement equation of the non-homogenous for the MCPA of the micropump, depends on the applied voltage and pressure load together with the material and physical properties. The electric-solid coupling of the piezoelectric actuator and the silicon diaphragm layer under the effect of applied voltage load, and the silicon-fluid coupling under the uniform fluid pressure were simulated by numerical modelling with finite elements. In addition, the maximum displacements of the MCPA with silicon exposed to uniform flow pressure and electric voltage load were measured at different frequencies experimentally. It was observed that the results obtained from the analytical model, finite element analysis and experimental studies were sufficiently compatible with each other. Using the verified analytical model, the effects of layer thicknesses, layer diameters and adhesive layer on actuator static displacement performance are discussed.

Lead Free Multilayer Piezoelectric Actuators by Economically New Approach

The replacement of lead zirconate titanate ceramics (PZTs), with a lead-oxide (PbO)-free alternative is the subject of intense investigation worldwide. In this research, a cheap reliable methodology for the fabrication of multilayers (MLs) of lead-free potassium sodium niobate (KNN)-based ceramics is presented without the need for vacuuming and/or hot isostatic pressing of the tape. The thickness per active layer was 193 μm and 102 μm for the 10 and 16 layer MLs actuators, respectively. Effective d33 (piezoelectric coefficient), effective d33∗ (electrostrain coefficient), bi-polar strain (Smax), max displacement, dielectric constant (ϵr) and loss (tanδ) are 2500 pC/N, 4604 pm/V, 0.17%, 2.2 μm, 1812 and 2% at 1 kHz, respectively, where the effective d33 or d33∗ is the total output of all layers together. The ultimate target materials for potential substitution with KNN-based ceramics and MLs are commercial PZT-4 and PZT-8.

Design, modeling and testing of d33-mode surface-bondable multilayer piezoelectric actuator

In this work, a surface-bondable multilayer piezoelectric actuator, which utilizes the ‘33’ electromechanical coupling for actuation, has been designed, modeled and tested. This actuator was developed to excite thick and stiff structures. The most commonly used form of piezoelectric actuator—the piezoelectric patches—are typically used for actuating thin beams, plates and shells. On the other hand, for actuating large, thick and stiff structures, piezoelectric stack actuators are preferred, due to their ability to generate larger block forces. But, unlike the piezoelectric patches, which are just bonded to the surface of the substructure with epoxy adhesive, the implementation of the stack actuators present certain drawbacks. Traditionally, the stack actuators have to be either integrated into the structure, or be utilized like an electrodyanmic exciter. Both of these methodologies of actuation are accompanied by several complications—large weight penalty being one of them—which render the choice of stack actuators undesirable for several applications. To overcome these shortcomings, and to offer a feasible solution, the concept of the surface-bondable multilayer piezoelectric actuator is proposed in this article. Besides retaining the actuation capabilities of a regular stack actuator, the design of the surface-bondable multilayer piezoelectric actuator allows it to be bonded to the surface of the substructure (like a piezoelectric patch). Thus, this design allows us to access the best of both worlds—the ease of implementation achieved with the patches, and the high actuation capability of the stack actuators. The design of the actuator, the inspiration for the design, the mechanism of operation of the actuator, its performance against other piezoelectric-based actuation methodologies, and the experimental validation of the concept, form the contents of the article.