In this study, we utilized the tape-casting method to produce Pb-free (Na0·52K0·4425Li0.0375) (Nb0·8925Sb0·07Ta0.0375)O3 + 2 mol% MnCO3 + y mol% LiF (y = 0 to 3) piezoelectric ceramics. We ...investigated the impact of LiF sintering in a reduced atmosphere on microstructure, dielectric properties, impedance spectroscopy, and piezoelectric performance. By analyzing the degree of diffuse phase transition, we observed increased density and enhanced long-range order in the sample doped with 1 mol% LiF, which exhibited optimal piezoelectric properties (d33 = 265 pC/N and kp = 0.437) and a minimal diffusion parameter. Moreover, LiF doping enabled sintering at 1020 °C under low PO2, facilitating potential co-firing with Cu inner electrodes to further enhance the piezoelectric performance. Using the optimized parameters, we fabricated a cross-type triaxial piezoelectric accelerometer, demonstrating sensitivities of 2.33, 2.44, and 10.6 mV/g along the X, Y, and Z axes, respectively, with a resonance frequency of ∼2600 Hz and frequency range of ∼1300 Hz. This accelerometer holds promise for vibration measurements in low-frequency mechanical systems.
A seismic data acquisition system based on wireless network transmission is designed to improve the low-frequency response and low sensitivity of the existing acquisition system. The system comprises ...of a piezoelectric transducer, a high-resolution data acquisition system, and a wireless communication module. A seismic piezoelectric transducer based on a piezoelectric simply supported beam using PMN-PT is proposed. High sensitivity is obtained by using a new piezoelectric material PMN-PT, and a simply supported beam matching with the PMN-PT wafer is designed, which can provide a good low-frequency response. The data acquisition system includes an electronic circuit for charge conversion, filtering, and amplification, an FPGA, and a 24-bit analog-to-digital converter (ADC). The wireless communication was based on the ZigBee modules and the WiFi modules. The experimental results show that the application of the piezoelectric simply supported beam based on PMN-PT can effectively improve the sensitivity of the piezoelectric accelerometer by more than 190%, compared with the traditional PZT material. At low frequencies, the fidelity of the PMN-PT piezoelectric simply supported beam is better than that of a traditional central compressed model, which is an effective expansion of the bandwidth to the low-frequency region. The charge conversion, filtering, amplification, and digitization of the output signal of the piezoelectric transducer are processed and, finally, are wirelessly transmitted to the monitoring centre, achieving the design of a seismic data acquisition system based on wireless transmission.
A sandwiched piezoelectric accelerometer is developed and optimized for acquiring low-frequency, wide-band seismic data. The proposed accelerometer addresses the challenges of capturing seismic ...signals in the low-frequency range while maintaining a broad frequency response through the design of multi-stage charge amplifiers and a sandwiched structure. The device’s design, fabrication process, and performance evaluation are discussed in detail. Experimental results demonstrate its performance in amplitude and phase response characteristics.
The wind turbine is rapidly becoming one of the world's most significant renewable energy sources. Wind turbines must be massive to increase amounts of electrical energy. The blades of a wind turbine ...are commonly made of fiber materials due to their low cost and low weight properties. However, blades are affected by gusts of wind, poor climate factors, uncertain wind loads, lightning storms, and gravity loads, resulting in a surface crack of the blade. As a result, it is important to monitor the state of each wind turbine and its location fault condition. In this research, a cuckoo-optimized modular neural network (COMNN) is proposed for detecting and classifying a crack in the blades of a wind turbine. The method is created using a piezoelectric accelerometer to calculate the blade vibration response when it is energized. Cuckoo optimization is applied to initialize and adjust the weight vector of the Modular Neural Network. The experimental result shows the COMNN accurately detects and classifies faults in an acceptable time. The proposed approaches classify the fault type with an accuracy 98.1 % higher than the existing techniques, such as convolutional neural networks (CNN), recurrent neural networks (RNN), and artificial neural network ANN + support vector machine (SVM) algorithms.
L'éolienne est rapidement devenue l'une des sources d'énergie renouvelables les plus importantes au monde. Les éoliennes doivent être massives pour augmenter les quantités d'énergie électrique. Les pales d’une éolienne sont généralement constituées de matériaux fibreux en raison de leur faible coût et de leur faible poids. Cependant, les pales sont affectées par des rafales de vent, des facteurs climatiques défavorables, des charges de vent incertaines, des orages et des charges gravitationnelles, ce qui entraîne une fissure superficielle de la pale. De ce fait, il est important de surveiller l’état de chaque éolienne et son état de défaut de localisation. Dans cette recherche, un réseau neuronal modulaire optimisé pour le coucou (COMNN) est proposé pour détecter et classer une fissure dans les pales d'une éolienne. La méthode est créée à l’aide d’un accéléromètre piézoélectrique pour calculer la réponse vibratoire de la lame lorsqu’elle est sous tension. L'optimisation Cuckoo est appliquée pour initialiser et ajuster le vecteur de poids du réseau neuronal modulaire. Le résultat expérimental montre que le COMNN détecte et classe avec précision les défauts dans un délai acceptable. Les approches proposées classent le type de défaut avec une précision 98,1 % supérieure aux techniques existantes, telles que les réseaux de neurones convolutifs (CNN), les réseaux de neurones récurrents (RNN) et les algorithmes de réseau de neurones artificiels ANN + support vector machine (SVM).
This article introduces a novel data acquisition system aimed at condition monitoring (CM) of complex industrial machinery and plants. Current commercial solutions can be divided into two groups: 1) ...high resolution and 2) data rate rack systems or distributed systems usually at the price of lower performance. The proposed solution aims at filling this gap. It relies on a daisy-chain digital bus architecture, featuring a main node and a series of subordinate nodes, which have been designed to collect data from both analog and digital transducers. It follows that the system is highly scalable and easily reconfigurable: the number and the type of transducers, ranging from low-cost micro electromechanical systems to high quality piezoelectric sensors, can be optimized to match each specific measurement requirements, even after the installation of the system. The proposed technology supports up to 32 channels at 48 kS/s, and guarantees the perfect synchronization of all signals regardless of the transducer type and its position along the bus, allowing to perform advanced data analysis. The system performance is at first evaluated with laboratory tests, then in the scenario of CM of rolling bearing faults, demonstrating good sensitivity and coherence between different accelerometer types.
Microelectromechanical (MEMS) piezoelectric accelerometers are diversely used in consumer electronics and handheld devices due to their low power consumption as well as simple reading circuit and ...good dynamic performance. In this paper, a tri-axial piezoelectric accelerometer with folded beams is presented. The four beam suspensions are located at two sides of the mass aligned with edges of the mass, and the thickness of the beams is the same as the thickness of the mass block. In order to realize the multi-axis detection, a total of 16 sensing elements are distributed at the end of the folded beams. The structural deformations, stress distribution, and output characteristics due to the acceleration in
,
, and
-axis directions are theoretically analyzed and simulated. The proposed accelerometer is fabricated by MEMS processes to form Mo/AlN/ScAlN/Mo piezoelectric stacks as the sensing layer. Experiments show that the charge sensitivity along the
,
, and
-axes could reach up to ~1.07 pC/g, ~0.66 pC/g, and ~3.35 pC/g. The new structure can provide inspiration for the design of tri-axial piezoelectric accelerometers with great sensitivity and linearity.
This paper presents the design and testing of a one-axis piezoelectric accelerometer made from cellulose paper and piezoelectric zinc oxide nanowires (ZnO NWs) hydrothermally grown on paper. The ...accelerometer adopts a cantilever-based configuration with two parallel cantilever beams attached with a paper proof mass. A piece of U-shaped, ZnO-NW-coated paper is attached on top of the parallel beams, serving as the strain sensing element for acceleration measurement. The electric charges produced from the ZnO-NW-coated paper are converted into a voltage output using a custom-made charge amplifier circuit. The device fabrication only involves cutting of paper and hydrothermal growth of ZnO NWs, and does not require the access to expensive and sophisticated equipment. The performance of the devices with different weight growth percentages of the ZnO NWs was characterized.
A vector hydrophone is an underwater acoustic sensor that can detect the direction of a sound source. Wide-band characteristics and high sensitivity enhance the performance of underwater surveillance ...systems in complex environments. A vector hydrophone comprising a triaxial piezoelectric accelerometer and spherical hydrophone was fabricated and tested in the air and underwater. The vector hydrophone was designed to exceed the quantitative figures of merit (i.e., receiving voltage sensitivity and bandwidth) of commercially available hydrophones. Accelerometer performance was enhanced by placing a pair of piezoelectric single crystals on each axis and modifying the seismic mass material. The receiving voltage sensitivity of the omnidirectional hydrophone was approximately −160 dB relative to 1 V/μPa with the amplifier in water; the sensitivity of the accelerometer exceeded 300 mV/g in air and −215 dB relative to 1 V/μPa underwater over the frequency range of interest. The receiving directivity of the vector hydrophone was validated underwater, which confirmed that it could detect the direction of a sound source.
A theoretical and experimental study on the design-to-performance characteristics of a compression-mode Pb(Zr,Ti)O3-based piezoelectric accelerometer is presented. Using the metamodeling to ...approximate the relationship between the design variables and the performances, the constituent components were optimized so that the generated electric voltage, representing sensitivity, could be maximized at different set values of the resonant frequency (25–40 kHz). Four kinds of optimized designs were created and fabricated into the accelerometer modules for empirical validation. The accelerometer modules fabricated according to the optimized designs were highly reliable with a broad range of resonant frequency as well as sufficiently high values of charge sensitivity. The fixed (or mounted) resonant frequency was between 16.1–30.1 kHz based on the impedance measurement. The charge sensitivity decreased from 296.8 to 79.4 pC/g with an increase of the resonant frequency, showing an inverse relation with respect to the resonant frequency. The design-dependent behaviors of the sensitivity and resonant frequency were almost identical in both numerical analysis and experimental investigation. This work shows that the piezoelectric accelerometer can be selectively prepared with best outcomes according to the requirements for the sensitivity and resonant frequency, fundamentally associated with trade-off relation.
In this study, we attempt to design a new square MEMS lead-free piezoelectric accelerometer that can be used simultaneously in a wider frequency range than has been available in the past and in low-G ...sensing environments with high accuracy and low transverse sensitivity. Low transverse sensitivity is an important factor for high-accuracy accelerometers. The device is designed through the use of a structural formula, and ANSYS software is used to simulate the vibration mode and resonance frequency of the device, after which the MEMS process is used to complete the fabrication of the devices. The performance of the proposed device indicated that the resonance frequency was 1740 Hz, with a simulation error of only 3.3%; the Z-axis sensitivity was 1.96 mV/g, and the transverse sensitivity ratio was 0.6%. To the best of the author's knowledge, the transverse sensitivity obtained in the present work is the lowest compared to the published data and specifications for commercial devices. It was successfully applied to a low-frequency robotic arm and a high-frequency turbo pump, where the operational status of the devices was monitored in-situ with high accuracy.
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