Positive Piezoelectric Effect Research Articles

Understanding and tuning negative longitudinal piezoelectricity in hafnia

Most piezoelectric materials exhibit a positive longitudinal piezoelectric effect (PLPE), while a negative longitudinal piezoelectric effect (NLPE) is rarely reported or paid much attention. Here, utilizing first-principles calculations, we unveil the origin of negative longitudinal piezoelectricity in ferroelectric hafnia by introducing the concept of weighted projected bond strength around cation in the c direction (WPBc), which is proposed to quantitatively characterize the asymmetric bonding stiffness along the strain direction. When the WPBc is anti-parallel to the direction of bulk spontaneous polarization, the polarization decreases with respect to tensile strain and leads to a negative piezoelectricity. Furthermore, to confirm the influence of WPBc on the piezoelectric effect and understand how the value of WPBc influences the piezoelectric coefficient e33, we acquire both the piezoelectric coefficient of doped hafnia and the corresponding bonding environment around each cation. The finding reveals that the more negative piezoelectric coefficient can be achieved through a concurrent achievement of the more negative average WPBc and the lower standard deviation (STD) of WPBc. In addition, the Sn-doped hafnia with the lowest average WPBc and smaller STD-WPBc is identified to have the highest piezoelectric coefficient (−2.04 C/m2) compared to other dopants, showing great potential in next-generation electromechanical devices.

Field experiments of watt-level piezoelectric energy harvester for different embedded depths

Road piezoelectric energy-harvesting technology uses the positive piezoelectric effect to convert vibrational energy produced by vehicular load to electrical energy. Road piezoelectric energy harvesters (RPEHs) are the core elements behind this technology. A new disc-type metal–piezoelectric ceramic transducer structure was developed to promote road piezoelectric energy collection and increase power generation from RPEHs. Finite element analyses and field tests were then conducted. The experimental results show that the disc transducers have excellent road compatibility. The greater the embedded depth of the transducer, the smaller is the output power of the RPEH; hence, an embedded depth of 2 cm was selected as the optimal value for comprehensive durability and electrical performance. When a small car travelling at a speed of 60 km/h passed over the RPEH embedded at a depth of 2 cm, a maximum voltage of 62 V, maximum current of 62 mA, and maximum utput power of 3844 mW (power density: 43 W/m2) were observed. The influence of the vehicle weight on the RPEH output power decreased with increase in speed. Therefore, this study confirms that the new disc-type RPEH is less costly, has excellent power generation, and requires less piezoelectric transducer material.

A flexible pressure sensor with interference immunity capability

PurposeFlexible pressure sensor arrays have promising applications in analog haptics, reconfiguration of sensory functions, artificial intelligence, wearable devices and human-computer interaction. The force disturbance generated by the connecting material between the sensor array units will reduce the detection accuracy of the unit. The purpose of this paper is to propose a flexible pressure sensor with interference immunity capability. A C-type bridge flexible piezoelectric structure is used to improve the pressure perturbation. The interference immunity capability of the sensor has been improved.Design/methodology/approachIn this paper, a C-type pressure sensor array structure by rapid injection moulding is manufactured through the positive piezoelectric effect of a piezoelectric material. The feasibility of C-type interference immunity structure in a flexible sensor array is verified by further analysis and experiment. A flexible pressure sensor array with C-type interference immunity structure has been proposed.FindingsIn this paper, we present the results of the perturbation experiment results of the C-type pressure sensor array, showing that the perturbation error is less than 8%. The test of the flexible sensor array show that the sensor can identify the curved angle of up to 120 °, and the output sensitivity of the sensor in the horizontal state reaches 0.12 V/N, and the sensor can withstand the pressure of 80 N. The flexible sensor can work stably in the stretch rate range of 0–8.6% and the stretch length range of 0–6 mm.Originality/valueIn this paper, C-type pressure sensor array structure is fabricated by rapid injection moulding for the first time. The research in this paper can effectively reduce the disturbance of input pressure on the sensor’s internal array and improve the output accuracy. The sensor can intuitively reflect the number of fingers sliding on the sensor by the order in which the maximum voltage appears. Due to the strong interference immunity capability and flexibility of the flexible sensor array mechanism, it has a broad application prospect in the practical fields of haptic simulation, perceptual function reconstruction, artificial intelligence, wearable devices and human–computer interaction.

A power generation device based on shape memory alloy and piezoelectric ceramic

A power generation technology that combines shape memory alloy (SMA) and piezoelectric ceramic is proposed. The piezoelectric ceramic is pulled by the deformed SMA to produce a positive piezoelectric effect, which eventually generates electrical energy. The research was conducted through structural design, collection and storage of electrical energy, and experimental verification. The experimental results show that the power generation device has an open circuit voltage of 11.6 V when heated by hot air at 100 °C. The device was used to charge a 1000μF/6.3 V capacitor through the energy harvesting circuit, and the final capacitor voltage was stabilized at about 6 V.

Research on a stacked high-sensitivity hydroacoustic transducer

PurposeIsland attack and defense, emergency rescue, scientific research, civilian fisheries and other fields are inseparable from timely, high-quality underwater communications. However light and other electromagnetic waves are severely attenuated in water, acoustic is currently the only energy carrier that can transmit signals over long distances in water. However, the complex water environment and serious interference bring serious challenges to underwater activities using underwater acoustic sensors-hydroacoustic transducers. Thus, this paper aims to develop a class of high reception sensitivity hydroacoustic transducer structures to provide research and utilization ideas for related scholars.Design/methodology/approachThe electromechanical coupling coefficient is improved by converting the thickness vibration mode of the piezoelectric ceramic into the longitudinal vibration mode of the piezoelectric pillars array, and no polymer is added between the piezoelectric pillars array to reduce lateral coupling as well as internal friction, which can thus reduce the energy losses. Radial stacking in parallel can also enhance the charge generated through the positive piezoelectric effect. The optimal parameters of the structure are determined by equivalent circuit method and finite element analysis, and a hydroacoustic transducer of this structure is fabricated finally.FindingsAccording to the standard test procedure, the hydroacoustic transducer was tested in water. The tests show that the conductance curve of the stacked high-sensitivity hydroacoustic transducer tested in the air is in good agreement with the simulation results. The resonant frequency is about 118 kHz, and the receiver sensitivity is −166 dB. The stacked material hydroacoustic transducer is in the high-frequency range and has a much higher sensitivity (−166 dB) than many types of hydroacoustic transducers fabricated by piezoelectric ceramic (less than −200 dB).Research limitations/implicationsAlthough the stacked high-sensitivity hydroacoustic transducer that the authors have fabricated has a performance improvement, it has a limitation. The hollow design of the pillar arrays increases the reception stress on each pillar, and the imposed pressure comes from water also increases simultaneously, so the depth of water that the stacked high-sensitivity hydroacoustic transducer can operate in may be slightly shallower than that made of a pure piezoelectric ceramic block or a piezoelectric ceramic material with polymer added. This will be a problem to be solved in a future deployment.Practical implicationsWhether it is marine scientific research or in various fields such as civil recreation and fishing, hydroacoustic communication and necessary underwater exploration are indispensable for acoustic waves. The hydroacoustic transducer is the sensor that sends and receives sound waves, so a lot of water equipment, such as yachts, sonar buoys, and so on, cannot be separated from the hydroacoustic transducer. In addition, the complexity of the water environment also requires a good performance of the hydroacoustic transducer to facilitate the convenience and effectiveness of subsequent signal processing. Therefore, hydroacoustic transducers have great market and commercial value.Social implicationsHydroacoustic transducers are not only of great commercial value but also have a significant impact on the military as well as on people’s livelihood. As we all know, in the area of submarine communication and underwater exploration, sonar is the main force. The performance of the hydroacoustic transducer directly affects the performance of the hydroacoustic signal processing system, and ultimately directly determines the success or failure of the mission. In addition, the large-scale replacement of hydroacoustic transducers on equipment requires the concerted efforts of a large number of practitioners, such as material scientists, structural scientists, mathematicians and so on. Therefore, the rise of hydroacoustic transducers has given rise to a large number of learning positions as well as employment positions.Originality/valueTo enhance the reception sensitivity of the hydroacoustic transducer, the authors have optimized the existing hydroacoustic transducer materials and structures to propose a stacked sensitive element, which can effectively enhance the electromechanical conversion coefficient of the piezoelectric material. Furthermore, the authors have manufactured a hydroacoustic transducer using the proposed stacked sensitive element. The test results of the hydroacoustic transducer also show that the designed stacked sensitive element is of great help to enhance the reception sensitivity of the hydroacoustic transducer.

Detection of avian influenza virus H9N2 based on self-driving and self-sensing microcantilever piezoelectric sensor

In this article, we used the self-excitation and self-inductance characteristics of polyvinylidene fluoride (PVDF) piezoelectric materials, combined with the powerful signal processing and calculation analysis capabilities of integrated circuits, for the first time to explore a set of microcantilever sensor "readout system" without additional driver (self-driving) and can realize self-sensing external signal (self-sensing). It was successfully applied to the unlabeled detection of avian influenza virus (AIV) H9N2. The specific force of the antigen-antibody complexes on the surface of the microcantilever leads to the change of the stress of the cantilever, which drives the constructed detection device, and does not require an additional excitation source to drive it, that is, the self-driving part. At the same time, due to the movement of piezoelectric charges in the film caused by the positive piezoelectric effect of the PVDF film, self-inductive charges are generated on the surface of the sensor dielectric. The charge signal is converted into a voltage signal, and the sensing part is completed, that is, self-sensing. The immunosensor has a linear range of 100-1000 ng/mL with a detection limit of 2.9 ng/mL. The method will also open up a new avenue for the detection of other analytes based on antigen-antibody responses.

Development and Characterization of ZnO Piezoelectric Thin Film Sensors on GH4169 Superalloy Steel Substrate by Magnetron Sputtering.

At present, piezoelectric sensors are primarily applied in health monitoring areas. They may fall off owing to the adhesive’s durability, and even damage the monitored equipment. In this paper, a piezoelectric film sensor (PFS) based on a positive piezoelectric effect (PPE) is presented and a ZnO film is deposited on a GH4169 superalloy steel (GSS) substrate using magnetron sputtering. The microstructure and micrograph of ZnO piezoelectric thin films were analyzed by an X-ray diffractometer (XRD), energy dispersive spectrometer (EDS), scanning electron microscope (SEM), and atomic force microscope (AFM). The results showed that the surface morphology was dense and uniform and had a good c-axis-preferred orientation. According to the test results of five piezoelectric sensors, the average value of the longitudinal piezoelectric coefficient was 1.36 pC/N, and the average value of the static calibration sensitivity was 19.77 mV/N. We selected the sensor whose parameters are closest to the average value for the dynamic test experiment and we drew the output voltage response curve of the piezoelectric film sensor under different loads. The measurement error was 4.03% when repeating the experiment six times. The research achievements reveal the excellent performance of the piezoelectric film sensor directly deposited on a GH4169 superalloy steel substrate. This method can reduce measurement error caused by the adhesive and reduce the risk of falling off caused by the aging of the adhesive, which provides a basis for the research of smart bolts and guarantees a better application in structural health monitoring (SHM).

Degradation State Identification Method for Piezoelectric Ceramic of Ultrasonic Motor Based on Segmented Fractal Dimension and Sparse Representation

Abstract Crack on piezoelectric ceramic is the main reason leading to the degradation of ultrasonic motors. Monitor electrode voltage generated by the positive piezoelectric effect is usually used to monitor the vibration of stator. However, the complexity of monitor electrode voltage signal changes slightly until failure state because of the bonding layer between piezoelectric ceramic and metal elastomer, and it brings difficulties for the degradation state identification. In order to improve the accuracy rate, a method based on segmented fractal dimension and sparse representation was presented in this article. Firstly, segmented fractal dimension was proposed to extract the complexity information of local signal, and the ones of standard samples were taken as the atoms to construct a dictionary. Then, sparse representation of the test sample was calculated according to the constructed dictionary, and the specific steps for the solution were also detailed. Lastly, the test sample’s deviation vectors corresponding to different degradation states were obtained, and the modulus of the vectors were employed to identify the degradation state. The experimental results show that this method is feasible and effective for the degradation state identification of piezoelectric ceramic. It is meaningful for the condition-based maintenance of ultrasonic motors.

Potential energy analysis based on piezoelectric cantilever beam structure

The piezoelectric vibration energy collection technology utilizes the positive piezoelectric effect of the piezoelectric material, and collects the energy by attaching the material to a clamping structure and deforming under the external excitation, thus accumulating the charge and generating the potential difference. In this paper, the cantilever beam is used as a clamping structure because of its large deflection and simple structure. In this paper, the raindrop impulsion is applied to the piezoelectric material, the piezoelectric vibration energy capture device is used to improve the energy collection efficiency, and the electromechanical coupling model is established to simplify the potential energy analysis by using the conservation of energy and Newton’s second law. In this paper, Runge-kutta method is used to simulate the differential equation, which reduces the computational cost of the system and has a certain precision for analysis and solution. Based on Al-‘Ula’s Bernoulli beam theory, the model was simulated by using the differential equation method and the ordinary differential equation group.

Octopus-shaped self-powered motion sensor based on the triboelectric and piezoelectric effect

ABSTRACT Multifunctional motion sensors have broad applications in the field of the internet of things (IoT). An octopus-shaped self-powered motion sensor is proposed to monitor the acceleration, motion direction, rotation speed and angle of objects. The charge transfer analysis of the sensor is carried out based on the positive piezoelectric effect, contact electrification effect and electrostatic induction. The influence of the surface microstructure and doping ZnO on the sensor sensitivity is investigated, and the improved film increases the sensor sensitivity by 13.58%. It is found that the output voltage decreases as the frequency increases. At the same frequency, the sensor output voltage amplitude is proportional to the acceleration amplitude. The test results show that the sensor can identify the motor rotation speed and angle, and the linear running direction and the motion state of the sweeping robot. Furthermore, the proposed sensor is cheap and beneficial for large-scale use.

Theoretical research and application development of self-sensing micro-flow injection device

In this study, the main content is based on theory and application of piezoelectric ceramic digital micro-injection, analyzing the first inverse piezoelectric effect and secondary positive piezoelectric effect of piezoelectric ceramics through theory and experiments, and using its principle to design self-sensing digital micro-injection structure. This paper designs a kind of digital micro-injection device which is based on the first inverse and secondary positive piezoelectric effect by according to the theoretical research and experimental verification of piezoelectric ceramic’s piezoelectric effect. Push the syringe plunger under the action of the piezoelectric ceramic’s first reverse piezoelectric effect to achieve a fluid flowing. At the same time, secondary piezoelectric effect can sense the injection volume to achieve self-sensing microinjection. Designing the overall structure of the program and validate the feasibility of the program is reasonable and practicable through feasibility experiments.

Noninvasive Passive Measurement of Multiphase Currents in IoT

The feasibility and the diversity of cantilever-based current sensing mechanism, which mainly comprised a cantilever with a permanent magnet on its free end, are verified for desirable applications of wireless sensor network (WSN) in Internet of Things (IoT). In the noninvasive multiphase current measurement, the applied current induced magnetic force is passively converted into a cantilever vibration via the magnet. The cantilever vibration can be further converted to an output voltage as a function of the applied current via diverse detecting units, enabling the diversity of cantilever-based current sensing mechanisms. In this article, cantilever-based methodology is verified to be applicable to multiphase current measurements, with considering decoupling and reconstructing in case of unbalanced ones. As a typical demonstration, three-phase four-wire ac current is passively measured via the positive piezoelectric effect of the piezoelectric detecting unit. Since the measurement of current is physically the noninvasive passive measurement of the gradient of the superimposed magnetic field, the cantilever-based current sensing methodology is applicable to a wide range of diverse current measurements of WSN in various IoT use cases.

An experimental study on a novel cylinder harvester made of L-shaped piezoelectric coupled beams with a high efficiency

In view of the unsatisfactory utilization efficiency of the piezoelectric patches used in the conventional harvesters, this research develops a novel efficient cylinder energy harvester made of L-shaped piezoelectric coupled beams by fully using the positive piezoelectric effect of the piezoelectric patch. Due to lack of accurate theory model of the L-shaped beam, experimental research is employed to study the advantages of the developed harvester which includes a pair of stators, a rotor and a cylindrical shell. Sets of stator specimens, a rotor, and a cylindrical shell are customized and five groups of experiments are conducted. The influences of some factors on the output voltage and power from an L-shaped beam are tested and analyzed. The output power and peak-to-peak voltage at a resonance can easily reach up to 2.35 mW and 50 V for a piezoelectric patch with a dimension of 38 mm × 13 mm × 0.5 mm of an L-shaped beam in the vibration process. This research provides an ingenious and compact structure for energy harvesting from ambient vibration such as wind and its effectiveness and efficiency are validated through a series of experiments.

Nonlinear Dynamics of Composite Microsheet with Graphene Skins in Non-uniform Thermal Field

The effects of different parameters on the nonlinear dynamic characteristics of macrofiber composite (MFC) microsheet with graphene (GP) skin under non-uniform thermal field are investigated. Firstly, the physical parameters of the MFC–GP structure are calculated by the mixing rule, and the constitutive equations of the structure are set up by employing the Eringen theory. The nonlinear dynamic equations of the microsheet are obtained by using Hamilton’s principle. Then, the heat conduction equations of the microsheet are considered, adopting Green and Naghdi’s generalized thermoelasticity theory. According to the Galerkin weighted residual method, the thermoelasticity coupling equations of the structure are obtained. Meanwhile, the influence of the positive piezoelectric effect of GP and MFC on the vibration response of the structure is also investigated. The nonlinear dynamic governing equations including displacement, coupled thermoelasticity, and electricity field are discretized by the Galerkin method. The effects of non-local parameter, volume fraction of GP, and thermal and electricity coupling coefficients on structural dynamic behavior are discussed in the numerical simulation.

Metro Vehicle Axle Temperature Monitoring Device Based on Piezoelectric Vibration

The axle temperature monitoring of subway vehicles is a key technology to ensure the safety of trains. The existing axle temperature monitoring system is monitored by using trackside equipment or using axle temperature test paper, the system has the inferiority of poor real-time performance. In order to realize real-time and online monitoring of axle temperature, this paper presents a subway axle temperature monitoring device based on vibration energy recovery. The device is installed on the shaft end of the train axle, and uses the positive piezoelectric effect of piezoelectric ceramics to absorb vibration energy into electric energy, and continuously sends temperature signal through the radio frequency module to realize real-time monitoring of train axle temperature. A mathematical model of piezoelectric vibrator power output was established to obtain design parameters suitable for rail vehicle vibration, and the Ansys Workbench finite element analysis software was used for theoretical simulation verification. Finally, an experimental model was built and a vibration test was carried out on Shanghai metro line 1. The results show that the axial temperature monitoring device based on piezoelectric vibration can effectively obtain the axial temperature data and realize the online monitoring function.

Scale-dependent pull-in instability of functionally graded carbon nanotubes-reinforced piezoelectric tuning nano-actuator considering finite temperature and conductivity corrections of Casimir force

A scale-dependent analytical model is presented to solve the nonlinear pull-in instability of functionally graded carbon nanotubes (CNTs) reinforced nano-actuator with piezoelectric layer considering high order-corrected electrostatic pressure and finite temperature and conductivity corrections of Casimir force. Based on Eringen’s nonlocal elasticity theory considering the long range forces among atoms, and geometrical nonlinearity, the electro-thermo-mechanical coupling governing equation of nano-actuator is derived, and solved by utilizing natural mode function and Galerkin’s decomposition method. The higher-order corrected model of electrostatic force with fringing field effect accounting for large gap and geometrical nonlinearity is employed. The results indicate that pull-in voltage decreases with increase of positive piezoelectric effect but increases with increment of negative piezoelectric effect. Pull-in voltage declines as the piezoelectric layer thickness of nano-actuator increases. Casimir force appears in more significant effect on the pull-in voltage of nano-actuator than that of van der Waals force, which shows that the analysis of nanoscale devices cannot neglect the influences of intermolecular forces within sub-micron separations. Finally, the coupling influences of van der Waals force and Capillary force on pull-in voltage are compared.

Piezoelectric Vibration Energy Harvesting Device Combined with Damper

Piezoelectricity is a type of material that enables mechanical energy and electrical energy to be interchangeable, which can be divided into positive piezoelectric effect and inverse piezoelectric effect. The positive piezoelectric effect is that the electric dipole moment of material generates changes when the piezoelectric material is subjected to pressure, resulting in electrical energy. Conversely, the inverse piezoelectric effect is the process of electrical energy converted into mechanical energy.

벌집형 압전 발전 소자의 구동방식에 따른 출력 특성

Recently, energy harvesting technology is increasing due to the fossil fuel shortages. Energy harvesting is generating electrical energy from wasted energies as sunlight, wind, waves, pressure, and vibration etc. Energy harvesting is one of the alternatives of fossil fuel. One of the energy harvesting technologies, the piezoelectric energy harvesting has been actively studied. Piezoelectric generating uses a positive piezoelectric effect which produces electrical energy when mechanical vibration is applied to the piezoelectric device. Piezoelectric energy harvesting has an advantage in that it is relatively not affected by weather, area and place. Also, stable and sustainable energy generation is possible. However, the output power is relatively low, so in this paper, newly designed honeycomb shaped piezoelectric energy harvesting device for increasing a generating efficiency. The output characteristics of the piezoelectric harvesting device were analyzed according to the change of parameters by using the finite element method analysis program. One model which has high output voltage was selected and a prototype of the honeycomb shaped piezoelectric harvesting device was fabricated. Experimental results from the fabricated device were compared to the analyzed results. After the AC-DC converting, the power of one honeycomb shaped piezoelectric energy harvesting device was measured 2.3[mW] at road resistance 5.1[<TEX>$K{\Omega}$</TEX>]. And output power was increased the number of harvesting device when piezoelectric energy harvesting device were connected in series and parallel.

Investigation on Multi-Piezoelectric Effects from the First Positive Piezoelectric Effect

Based on the traditional piezoelectric effect theory, the process of multi-piezoelectric effects generation is analyzed and the theory of the secondary and tertiary piezoelectric effect is deduced by four kinds of piezoelectric equations. Experimental research is performed through the PZT-5 piezoelectric ceramics stack, the existence of multi-piezoelectric effects is verified and experimental data is obtained under certain boundary conditions. The experimental data results show that if an external force which is applied to the positive piezoelectric effect is 400, the displacement generated by the secondary converse piezoelectric effect is 0.16. Therefore, starting from the first positive piezoelectric effect of the piezoelectric ceramics under applied force, the displacement generated by the secondary converse piezoelectric effect and the voltage generated by the tertiary positive piezoelectric effect are all linear with the applied force.

Research of Street Lighting System Based on Piezoelectric Energy Generator

The paper do some research on the positive piezoelectric effect of piezoelectric ceramic stack. Piezoelectric energy generator is laid on the highway surface, and using the stress which is generated by piezoelectric device to generate electric energy when the vehicle is passing. The generated electric energy is stored in the lithium battery package for street lighting at night after the circuit adjustment. The experimental demonstration and theoretical analysis show that the electric energy generated in piezoelectric stack can be stored in 12V-12Ah lithium battery package within 12h by the circuit of 3F ultracapacitor and LM2575HVT-12V regulator when the output voltage of LM2575HVT-12V is 12V. 12V-12Ah lithium battery package supply energy to the 12V, 12W high power LED lighting for 12h, and meeting the street lighting standards.