Piezoelectric Transducer Applications Research Articles

Reducing Uncertainty in Shunt Damping by Model-Predictive Product Stiffness Control in a Single Point Incremental Forming Process

The stiffness of metal formed products strongly affects the dynamic behavior of structures in which they are integrated. Forming processes underlie short and long-term variations which cause the stiffness to be uncertain.In the application of resonant shunted piezoelectric transducers for vibration attenuation, uncertain stiffness may cause significant reduction in the vibration attenuation performance due to imprecise tuning. In the past, large efforts were made to control one or more geometrical feature of products while weightier features that cause uncertainty have not been addressed.In this paper, a single point incremental forming process of a membrane-like spring element on a servo press with a 3 degrees of freedom drive system is investigated. This spring element is used in a beam support for lateral vibration attenuation with resonant shunted transducers as well as axial buckling stabilization.To reduce uncertainty caused by process variations, an offline closed-loop control of product stiffness is presented. Different product and forming criteria are integrated into a control approach based on an optimization routine. By making use of a model-based prediction of the product properties, the approach shows how to realize a multi-objective control.

Experimental Study of the Focused Ultrasonic System for Differential Diagnostics of the Human Hearing

In this paper the analysis of relevance and novelty of application of piezoelectric transducer for noninvasive diagnostics of a cochlea of the human by means of the focused ultrasound is carried out. To date, clinical use of ultrasound is numerous and diverse, and ultrasound diagnosis is one of the fastest growing methods in medicine. Revealed a previously unknown effect of spatial notch filtering quarter wavelength layers diffuse heat radiation. It is shown that the effect, together with a focused acoustic thermometer, allows for greater accuracy and allows measurement of the body's deep body temperature in real time.The design of the converter consists of a piezoceramic, an acoustic lens with the help of which the transformation of a flat wave front into an acoustic system with a flat piezoelement. The flat, concave lens is made of solid material, the rate of ultrasonic diffusion in which exceeds its value in water (biological tissue) for the studied acoustic system, organic glass was chosen. It is provided the theory, calculation and a design of measuring means: a high-frequency wattmeter for measurement of the electric power consumed by a piezoelectric transducer; the radiometer for measurement of acoustic power of the focused ultrasonic bunches. With their help detailed pilot study of the acoustic system is conducted, namely, parameters of her acoustic field and efficiency are determined. The theory, calculation and design are given: free float radiometer for measuring acoustic power of both focused and unfocused ultrashort beams; high-frequency wattmeter without active elements for measuring the power consumption of a piezus emitter.The experimental study of the layout of the acoustic focusing system is to measure the emitted acoustic and consumed electrical power of the piezoelectric element with the lens. The task of measuring acoustic power is solved using a radiometer. The measurement of the consumed electric power is made by means of a high-frequency wattmeter, which contains a multiplication scheme in the form of a circular scheme on four diodes and a current transformer. The received frequency dependences of radiated acoustic power, electric power consumed and the efficiency factor are obtained.The conclusion about expediency of use of this type of the electro-acoustic transducer for differential diagnostics of hearing of the human is drawn. The calculated intensity is sufficient for both diagnostic and therapeutic use of the developed acoustic system. This type of piezoelectric transducer will make it possible to distinguish between diseases of the middle ear of a person from internal diseases, and therefore to carry out differential diagnostics of the auditory system. This is especially important in clinical practice for choosing a further recovery strategy: if the loss occurs in the middle ear - the hearing aid is used, if in the inner one - is performed surgically by implantation of the cochlear implant.Ref. 10, fig. 6, tabl. 2.

Understanding the effect of porosity on the polarisation-field response of ferroelectric materials

This paper combines experimental and modelling studies to provide a detailed examination of the influence of porosity volume fraction and morphology on the polarisation-electric field response of ferroelectric materials. The broadening of the electric field distribution and a decrease in the electric field experienced by the ferroelectric ceramic medium due to the presence of low-permittivity pores is examined and its implications on the shape of the hysteresis loop, remnant polarisation and coercive field is discussed. The variation of coercive field with porosity level is seen to be complex and is attributed to two competing mechanisms where at high porosity levels the influence of the broadening of the electric field distribution dominates, while at low porosity levels an increase in the compliance of the matrix is more important. This new approach to understanding these materials enables the seemingly conflicting observations in the existing literature to be clarified and provides an effective approach to interpret the influence of pore fraction and morphology on the polarisation behaviour of ferroelectrics. Such information provides new insights in the interpretation of the physical properties of porous ferroelectric materials to inform future effort in the design of ferroelectric materials for piezoelectric sensor, actuator, energy harvesting, and transducer applications.

Reduction of Adherent Forces of Sedimentous Contaminants in Tunnel Drainage using Vibrations from Flexible and Transparent Organic Films

Tunnel drainage systems require regular maintenance to reduce the amount of calcite deposits, which can eventually obstruct the effluent and cause deterioration to the pipe lining. Current maintenance methods have high energy consumption and often result in pipe damage due to pipe blockage or solidified contaminants. In this study, the effectiveness of vibrations from a film type transducer in improving the cleaning efficiency of tunnel drainage systems was investigated. Our findings suggest that the vibrations produced by the transducer affected the shear resistance of the adherent contaminants in the drainage pipe. By reducing the shear resistance of sedimentous contaminants, drainage pipe maintenance can become more energy efficient. This study aims to provide data for the implementation of field applications of piezoelectric transducers for drainage systems.

Application of piezoelectric transducer in energy harvesting in pavement

Mechanical energy appears everywhere in the nature, road vibration energy created by the vehicle will not only do damage to pavement structure, but also is difficult to collect. Utilizing electromechanical conversion characteristics of piezoelectric material, gather the vibration energy when vehicle passing on the pavement, and design the piezoelectric transducer package box, for traffic lights along the roads, signs, and so on. Save the cost of laying long distance transmission line, also take full advantage of the loss of energy. Experiments of piezoelectric boxes has been conducted in pavement to prove the effectiveness of this product. This study shows that utilize piezoelectric technology in road energy harvesting is feasible and has a bright future.

A process chain for integrating piezoelectric transducers into aluminum die castings to generate smart lightweight structures

The application of piezoelectric transducers to structural body parts of machines or vehicles enables the combination of passive mechanical components with sensor and actuator functions in one single structure. According to Herold et al. [1] and Staeves [2] this approach indicates significant potential regarding smart lightweight construction. To obtain the highest yield, the piezoelectric transducers need to be integrated into the flux of forces (load path) of load bearing structures. Application in a downstream process reduces yield and process efficiency during manufacturing and operation, due to the necessity of a subsequent process step of sensor/actuator application. The die casting process offers the possibility for integration of piezoelectric transducers into metal structures. Aluminum castings are particularly favorable due to their high quality and feasibility for high unit production at low cost (Brunhuber [3], Nogowizin [4]). Such molded aluminum parts with integrated piezoelectric transducers enable functions like active vibration damping, structural health monitoring or energy harvesting resulting in significant possibilities of weight reduction, which is an increasingly important driving force of automotive and aerospace industry (Klein [5], Siebenpfeiffer [6]) due to increasingly stringent environmental protection laws. In the scope of those developments, this paper focuses on the entire process chain enabling the generation of lightweight metal structures with sensor and actuator function, starting from the manufacturing of piezoelectric modules over electrical and mechanical bonding to the integration of such modules into aluminum (Al) matrices by die casting. To achieve this challenging goal, piezoceramic sensors/actuator modules, so-called LTCC/PZT modules (LPM) were developed, since ceramic based piezoelectric modules are more likely to withstand the thermal stress of about 700°C introduced by the casting process (Flössel et al., [7]). The modules are made of low temperature cofired ceramic (LTCC) tapes with an embedded lead zirconate titanate (PZT) plate and are manufactured in multilayer technique. For joining conducting copper (Cu) wires with the electrode structure of the LPM, a novel laser drop on demand wire bonding method (LDB) is applied, which is based on the melting of a spherical CuSn12 braze preform with a liquidus temperature Tliquid of 989.9°C (Deutsches Kupfer-Institut Düsseldorf, [8]) providing sufficient thermal stability for a subsequent casting process.

Synthesis and Electrical Properties of New Lead‐free (100−x)(Li0.12Na0.88)NbO3–xBaTiO3 (0 ≤ x ≤ 40) Piezoelectric Ceramics

New lead‐free (100−x)Li0.12Na0.88NbO3‐xBaTiO3 (0 ≤ x ≤ 40) piezoelectric ceramics have been synthesized using conventional ceramics processing route. Structural analysis revealed an existence of morphotropic phase boundary (MPB), separating orthorhombic and tetragonal phases, between the BaTiO3 content, x = 10–12.5. A partial phase diagram has been established based on temperature‐dependent permittivity data for this new system and a almost vertical temperature‐independent MPB is observed. Improvement in electrical properties near MPB (e.g., for x = 12.5; εr = 8842 at Tm and 795 at room temperature, d33 = 30 pC/N, kp = 12.0%, Qm = 162, Pr = 11.2 μC/cm2, Ec = 19.2 kV/cm, = 174 pm/V) is observed, and is attributed to the ease of polarization rotation due to coexistence of orthorhombic and tetragonal phases. The results show that these materials could be suitable for piezoelectric vibrators and ultrasonic transducer applications. The sample with x = 25, also exhibited high dielectric permittivity, εr = 2400, and low dielectric loss, tanδ = 0.033 at room temperature which could be suitable for capacitor (X7R/Z5U) applications.

Influence of the excitation parameters of the mechanical subsystem on effectiveness of energy harvesting system

Piezoelectric transducers are used more and more often in modern technical devices. The wide range of their possible applications is a result of the possibility to use both direct and reverse piezoelectric effect. Nowadays, application of piezoelectric transducers in energy harvesting systems is getting more and more popular. It is caused by the easy way to convert energy of mechanical vibration to the electric voltage using piezoelectric transducers. This paper presents results of influence analysis of the vibrating mechanical subsystem's excitation parameters on the effectiveness of the system designed for energy harvesting. The considered vibrating system is a composite plate with piezoelectric transducer bonded to its surface. Vibrations of the system are excited by means of an actuator with possibility to change the excitation amplitude and frequency. Recovering of electrical energy from mechanical vibrations is possible by using the direct piezoelectric effect - generation of the electric voltage while the transducer is mechanically deformed. In carried out test Macro Fiber Composite (MFC) piezoelectric transducers were used. It was proved that the time that is necessary for switch on the output voltage in analyzed system depends on the frequency of the excitation.

An experimental investigation on the health monitoring of concrete structures using piezoelectric transducers at various environmental temperatures

The application of piezoelectric transducers in in situ health monitoring of concrete structures has been widely investigated. However, previous experimental studies were normally performed in an isothermal room environment, which offers insufficient considerations for temperature variations that real engineering structures experience in practical monitoring cases. In this article, the temperature effects on smart aggregate–based monitoring results are treated by performing active structural health monitoring on two plain concrete specimens at various temperatures. Experimental results show that the amplitude of the monitoring signal increases with temperature, with low-frequency signals being more sensitive to temperature variation while high-frequency signals less temperature dependent. This research demonstrates the necessity of temperature compensation in smart aggregate–based monitoring techniques.

Effect of excess of bismuth doping on dielectric and ferroelectric properties of BaBi4Ti4O15 ceramics

The effect of excess bismuth oxide Bi2O3 (2–10wt%) for processing BaBi4Ti4O15 (BBT) ceramics by solid state reaction has been investigated. The formation of a single phase and a change in the orthorhombic distortion are confirmed with varying excess of bismuth content. Changes in the density are marginal, and use of excess bismuth is seen to promote enhanced grain growth. Dielectric response is improved markedly exhibiting reduced dielectric losses and dispersion over a wide frequency range (10−3–106Hz). A high dielectric constant (ε′~226), low loss factor (tanδ~0.01) and low dc conductivity (σdc~10–14Ω−1cm−1) are achieved with an optimum content 6–8wt% of excess of bismuth oxide. Temperature dependent dielectric data fits well to the modified Curie–Weiss law and the frequency dependent maximum temperatures (Tm and Tm1) corresponding to real and imaginary parts of dielectric permittivity (ε′ and ε″) show a good fit to the non-linear Vogel–Fulcher (V–F) relationship. A clear relaxor behavior is observed with a degree of diffuseness, γ~1.97. Saturated hysteresis loops with high remnant polarization (Pr~12.5μC/cm2), low coercive fields (Ec~26kV/cm) are measured and a high piezoelectric coefficient (d33~29pC/N) is achieved in poled BaBi4Ti4O15 ceramics prepared with up to 8wt% of excess bismuth oxide. Such a relaxor ferroelectric material with high Curie temperature is useful for high temperature piezoelectric transducer applications.

0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 Thick Films for High-Frequency Piezoelectric Transducer Applications

The properties of 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (0.65PMN–0.35PT) thick films were studied for high-frequency piezoelectric transducer applications. The films were prepared by screen-printing a thick-film paste on platinized alumina substrates and subsequent sintering at 950 °C. The effective thickness-coupling factor of these films was close to 48%, which is comparable with bulk ceramics having the same compositions. Furthermore, simulations of two configurations representing one element of a high-frequency linear-array transducer (30 MHz) suggests that 0.65PMN–0.35PT thick-films in 50 Ω electrical matching environment improves the performance in comparison with standard Pb(Zr,Ti)O3 (PZT) compositions.

Integrated and Object-Oriented Mechatronic Modelling of Piezoelectric Transducers Using Linear Graphs

Piezoelectric transducers represent a key component in many mechatronic applications, and are used in both sensing and actuation modes. Modelling of these components is important in the analysis, design, and control of the associated systems. Specifically, a mechatronic approach to modelling, which is an integrated multi-domain approach, is desirable. This paper develops a novel and comprehensive object-oriented framework for mechatronic modelling of piezoelectric transducers using linear graphs. Unlike earlier work where piezoelectric transducers are modelled by an ideal transformer, the developed linear graph structures accurately and completely consider linear constitutive equations of the piezoelectric material. Developed models can be easily combined with the linear graph models of other system components, to form a complete and integrated mechatronic model of the overall system. Using the developed models and from the viewpoint of object-oriented modelling, novel and integrated mechatronic models are presented for several widely used applications of piezoelectric transducers, including piezoelectric accelerometer, piezoelectric stack actuator, hybrid piezoelectric actuator, and piezoelectric transducer for active vibration control using its self-sensing characteristic.

Fabrication and characterization of thick-film piezoelectric lead zirconate titanate ceramic resonators by tape-casting

In this paper, thick-film piezoelectric lead zirconate titanate (PZT) ceramic resonators with thicknesses down to tens of micrometers have been fabricated by tape-casting processing. PZT ceramic resonators with composition near the morphotropic phase boundary and with different dopants added were prepared for piezoelectric transducer applications. Material property characterization for these thick-film PZT resonators is essential for device design and applications. For the property characterization, a recently developed normalized electrical impedance spectrum method was used to determine the electromechanical coefficient and the complex piezoelectric, elastic, and dielectric coefficients from the electrical measurement of resonators using thick films. In this work, nine PZT thick-film resonators have been fabricated and characterized, and two different types of resonators, namely thickness longitudinal and transverse modes, were used for material property characterization. The results were compared with those determined by the IEEE standard method, and they agreed well. It was found that depending on the PZT formulation and dopants, the relative permittivities ε(T)(33)/ε(0) measured at 2 kHz for these thick-films are in the range of 1527 to 4829, piezoelectric stress constants (e(33) in the range of 15 to 26 C/m(2), piezoelectric strain constants (d(31)) in the range of -169 × 10(-12) C/N to -314 × 10(-12) C/N, electromechanical coupling coefficients (k(t)) in the range of 0.48 to 0.53, and k(31) in the range of 0.35 to 0.38. The characterization results shows tape-casting processing can be used to fabricate high-quality PZT thick-film resonators, and the extracted material constants can be used to for device design and application.

Morphotropic phase boundary and high temperature dielectric, piezoelectric, and ferroelectric properties of (1−x)Bi(Sc3/4In1/4)O3-xPbTiO3 ceramics

Piezoelectric ceramic (1 − x)Bi(Sc3/4In1/4)O3-xPbTiO3 (BSIPT) (0.45 ≤ x ≤ 0.70) solid solutions near the morphotropic phase boundary (MPB) were developed for high temperature piezoelectric transducer and actuator applications. It was found that the MPB composition of BSIPT ceramics was in the vicinity of x = 0.6, where it had relatively small tolerance factor t = 0.901 resulting in a high TC of 457 °C, and also optimal properties such as the high Pr = 25.4 μC/cm2, ɛr = 1153, d33 = 201 pC/N, kp = 0.34, and the low Ec = 23.5 kV/cm. Measurements also showed that the depoling temperature was 360 °C, about 200 °C higher than that of commercialized PZT ceramics, which indicated good temperature stability. BSIPT ceramics are promising candidates for high temperature applications.

Low‐Temperature Sintering and Properties of 0.98PZT–0.02SKN Ceramics with LiBiO2 and CuO Addition

The low‐temperature sintering behavior of Pb(Zr0.53, Ti0.47)O3–Sr(K0.25, Nb0.75)O3 (PZT–SKN) piezoelectric ceramics with LiBiO2 and CuO addition has been investigated. The addition of 6 wt% LiBiO2 or 1 wt% LiBiO2+1 wt% CuO promotes the sinterability of 0.98PZT–0.02SKN ceramics owing to the generation of a liquid phase, resulting in a reduction of sintering temperature by about 300°–350°C. The microstructure, dielectric, and piezoelectric properties of flux‐sintered ceramics were examined and compared with materials conventionally sintered at 1250°C. PZT–SKN ceramics with 1 wt% LiBiO2+1 wt% CuO addition were sintered to high density at 900°C for 1 h. The resulting samples exhibited a high‐field d33 piezoelectric coefficient of 415 pm/V with a Curie temperature Tc of around 351°C, dielectric constant ɛr of 1235, and planar coupling factor kp of 0.54. The reduced sintering temperature and short soaking time, together with the favorable dielectric and piezoelectric properties of the fluxed PZT–SKN ceramics, demonstrate the potential opportunity of integration with low‐temperature cofired ceramic materials and low‐fire electrode materials for the multilayer piezoelectric transducer application.

Application of piezoelectric transducers in simulated rainfall erosivity assessment

Rainfall simulators have often been used to mimic natural rainfall for studies of various land-surface and water interaction processes. The characteristics of the simulated rainfall are the main indicators used to judge the performance of the rainfall simulators. The aim of this study is to investigate the potential of piezoelectric transducers for measuring and evaluating a dripper-type simulated rainfall drop-size distribution (DSD) and kinetic energy (KE). The directly measured KE was significantly correlated with the estimated KE using the drop-size distribution and empirical rain drop fall velocity relationships. This result emphasizes the potential use of the piezoelectric sensor to directly measure and evaluate rainfall kinetic energy. Also, the relationship between rainfall intensity and KE showed good patterns of agreement between simulated rainfall and natural rainfall. Citation Abd Elbasit, M. A. M., Yasuda, H. & Salmi, A. (2011) Application of piezoelectric transducers in simulated rainfall erosivity assessment. Hydrol. Sci. J. 56(1), 187–194.

Remarkable Strontium B‐Site Occupancy in Ferroelectric Pb(Zr1−xTix)O3 Solid Solutions Doped With Cryolite‐Type Strontium Niobate

New high‐performance ferroelectric solid solutions based on Pb(Zr1−xTix)O3 (PZT), which are doped with cryolite‐type strontium niobate (SNO, Sr4(Sr2−2y/3Nb2+2y/3)O11+yVO;1−y with 0≤y≤1) and hence denoted PZT:SNO, and their microscopic structure and defect chemistry are described. Extended X‐ray absorption fine‐structure (EXAFS) analyses of PZT:SNO samples revealed that ∼10% of Sr2+ occupy the nominal B‐sites of the perovskite‐type PZT host lattice. This result is supported by EXAFS analyses of both a canonical SrTiO3 perovskite and two SNO model and reference compounds. Fit models that do not account for Sr2+ on B‐sites are ruled out. A clear Sr–Pb peak in Fourier‐transformed EXAFS data visually confirms this structural model. The generation of temporary oxygen vacancies and the intricate defect chemistry induced by SNO‐doping of PZT are crucial for the exceptional material properties of PZT:SNO. As a result, ferroelectric PZT:SNO solid solutions are very attractive for use in new and innovative piezoelectric actuator and transducer applications.

Biomedical instrumentation based on piezoelectric ceramics

New sensors and actuators based on emerging transducer technologies can play a crucial role in the field of biomedical instrumentation and rehabilitation technologies. Piezoelectricity and transducers based on the piezoelectric effect might lead to the adoption of compact sensor and actuator solutions in this field. This paper addresses a review of piezoelectric and piezoresistive transducer applications in the field of biomedical instrumentation. As an emerging application field, the potential implementation of these transducers in inertial motion analysis is addressed. The potential applications for these devices are high but we will focus on piezoelectric sensors in the area of inertial and portable biomechanical measurement systems and on piezoelectric actuators in active orthotics.

Piezoelectric transducer design via multiobjective optimization

The design of piezoelectric transducers is usually based on single-objective optimization only. In most practical applications of piezoelectric transducers, however, there exist multiple design objectives that often are contradictory to each other by their very nature. It is impossible to find a solution at which each objective function gets its optimal value simultaneously. Our design approach is to first find a set of Pareto-optimal solutions, which can be considered to be best compromises among multiple design objectives. Among these Pareto-optimal solutions, the designer can then select the one solution which he considers to be the best one. In this paper we investigate the optimal design of a Langevin transducer. The design problem is formulated mathematically as a constrained multiobjective optimization problem. The maximum vibration amplitude and the minimum electrical input power are considered as optimization objectives. Design variables involve continuous variables (dimensions of the transducer) and discrete variables (the number of piezoelectric rings and material types). In order to formulate the optimization problem, the behavior of piezoelectric transducers is modeled using the transfer matrix method based on analytical models. Multiobjective evolutionary algorithms are applied in the optimization process and a set of Pareto-optimal designs is calculated. The optimized results are analyzed and the preferred design is determined.

Quartz Crystal Microbalance for Bioanalytical Applications

AbstractFor Abstract see ChemInform Abstract in Full Text.