Piezoelectric Ceramic Sensors Research Articles

A Time-Frequency Domain Mixed Attention-Based Approach for Classifying Wood-Boring Insect Feeding Vibration Signals Using a Deep Learning Model.

Wood borers, such as the emerald ash borer and holcocerus insularis staudinger, pose a significant threat to forest ecosystems, causing damage to trees and impacting biodiversity. This paper proposes a neural network for detecting and classifying wood borers based on their feeding vibration signals. We utilize piezoelectric ceramic sensors to collect drilling vibration signals and introduce a novel convolutional neural network (CNN) architecture named Residual Mixed Domain Attention Module Network (RMAMNet).The RMAMNet employs both channel-domain attention and time-domain attention mechanisms to enhance the network's capability to learn meaningful features. The proposed system outperforms established networks, such as ResNet and VGG, achieving a recognition accuracy of 95.34% and an F1 score of 0.95. Our findings demonstrate that RMAMNet significantly improves the accuracy of wood borer classification, indicating its potential for effective pest monitoring and classification tasks. This study provides a new perspective and technical support for the automatic detection, classification, and early warning of wood-boring pests in forestry.

Damage Analysis of Urban Comprehensive Pipe Gallery Caused by Internal Gas Explosion Based on HHT

In this paper, the method of embedding piezoelectric ceramic sensors is used to test the damage of the materials and models of the urban comprehensive pipe gallery. The monitoring signal is processed by HHT method, and the frequency and energy changes of the piezoelectric signal before and after the explosion were analyzed, thus the damage characteristics of the urban comprehensive pipe gallery under the internal gas explosion are determined. The results show that in the gas explosion test inside the pipe gallery model, the waveform and peak value of the piezoelectric signal before and after the explosion did not change significantly, indicating that there was no obvious damage to the side wall of the integrated pipe gallery. However, after further time-frequency analysis of the piezoelectric signal by HHT, it is found that the dominant frequency of the piezoelectric signal after explosion has a downward trend, so it is judged that there is a small damage in the pipe gallery after explosion.

Defect Detection in Grouting Sleeve Grouting Material by Piezoelectric Wave Method

The construction defects in grouting sleeves can jeopardize the safety of precast reinforced concrete structures. Thus, efficient and accurate defect detection is critical in engineering construction. In this paper, a defect detection method based on piezoelectric wave theory was proposed. Two piezoelectric ceramics were arranged within the grouting sleeve. One piezoelectric ceramic was affixed on the top of the steel bar, while the other was embedded in the grouting material, serving as the driver and sensor, respectively. The compactness defects, air cavity defects, steel anchoring defects, and water–binder ratio defects were set in the grouting sleeves, and the trends in time domain signals and signal evaluation indicators based on the wavelet packet total energy value (WPTEV) of different specimens were investigated. Based on the WPTEV, the evaluation index (EI) was proposed. In addition, the effect of the grouting material’s age on the piezoelectric wave signal was verified. Furthermore, the influence of grouting material defects on signals was simulated in ABAQUS, and the time domain signals and wavelet packet energy of sensor signals for specimens with varying defect dimensions were evaluated. The results showed that: (1) The defects in the grouting materials reduced the stress waves propagated through the grouting materials, resulting in a decrease in attenuation and an increasing trend in the signal; (2) The peak-to-peak values of piezoelectric ceramic sensors and the WPTEV of the signal increased with the degree of defects, and the WPTEV was more pronounced. For specimen M68, the WPTEV was 3.3 times that of the healthy specimen, however, the peak-to-peak value was only 2.3 times that of the healthy specimen; (3) The degree of defects was accurately determined by the defect evaluation index (EI) based on the WPTEV; (4) The signal was significantly attenuated with the increase in the age of the grouting material, especially in the first three days, and finally the signal achieved a stable value; (5) The numerical simulation indicated that the defects in the length and thickness of the air cavity in the grouting material were efficiently detected by the proposed piezoelectric arrangement in this study.

An overpressure monitoring system based on PVDF integrated Electronic sensor with enhanced noise attenuation capability

The measurement of shockwave overpressure is of great significance for the safe use of explosives. The traditional overpressure monitoring systems are based on Integrated Electronics Piezo-Electric (IEPE) ceramic sensors. However, the brittleness of piezoelectric ceramic limits the application of overpressure monitoring system in high impact overpressure testing. Herein, a novel overpressure monitoring system based on Integrated Electronic Poly (vinylidene fluoride) (PVDF) (PFIE) sensor with electromagnetic interference shielding capability and parasitic vibration noise elimination function was designed for intense overpressure acquiring. PVDF, as a polymer, can endure much higher impact pressures compared to piezoelectric ceramics. However, its larger internal resistance makes it more prone to electromagnetic interference. To address this, an electromagnetic shielding structure was designed, incorporating an impedance matching circuit that effectively reduces the sensor's output impedance. Additionally, to mitigate excessive vibration noise during overpressure testing, the differential noise reduction technique has been implemented. Both the laboratory testing and the real blast testing with 10 kg trinitrotoluene were performed to validate the PFIE overpressure monitoring system. The result shows that the electromagnetic noise suppression ability of the PFIE overpressure sensors developed for the monitoring system was improved by 45 dB, and the parasitic vibration noise could be attenuated from 30 % to 1 %, what’s more the RMS errors of the overpressure dynamic parameters obtained by the monitoring system were below 10 %. This work has successfully addressed the noise sensitivity issue inherent in PVDF when used as a pressure sensor, capitalizing on its robust impact resistance. This approach has provided a viable solution for measuring overpressure in scenarios involving intense shock pressures, leveraging the strengths of PVDF in such demanding applications.

Ultrasonic monitoring of cement setting based on embedded sensor

The hydration property of cement directly affects the performance index of concrete, so it is necessary to monitor the hydration setting process of cement. The aim of this paper is to monitor the process of cement hydration setting by ultrasonic wave. Ultrasonic monitoring is a kind of dynamic non-destructive testing technology, which has the advantages of real-time, on-line and continuous. In this paper, an in-situ monitoring technology of cement hydration setting based on embedded piezoelectric ceramic sensor is introduced. The monitoring results show that the amplitude change of ultrasonic signal received by the sensor can indirectly reflect the change process of cement hydration solid and liquid, especially the initial setting node has a high catching ability.

Monitoring Soil-Pile Stripping Damage at Different Temperatures via Piezoelectric Ceramic Sensors

Large temperature differences exist between the winter and summer seasons in different regions of China. Such temperature differences, caused by seasonal changes, may affect the life cycles of piles. Under natural conditions, such as long-term operation under the ambient environment and loads, piles and the surrounding soil undergo peel damage. To study such peel damage between the pile and soil at different temperatures, we installed concrete test piles in soil and subjected them to different temperatures. A crack with a width of 2 cm, depth of 10 cm, and damage range of 90° was applied at the side of the piles. Furthermore, a horizontal impact load was applied near the top of the pile and a piezoelectric ceramic sensor was used to obtain the stress wave response signals. The experimental results reveal that with a decrease in the soil temperature, the amplitude and fluctuation range of the signals received by the piezoelectric sensor decreased. According to the experimental results, in the group with the greatest influence of temperature, keeping other conditions unchanged and setting different crack depths, the horizontal impact load can also be introduced to observe the frequency change. It can be observed that the larger the crack depth, the smaller the frequency. Finally, ABAQUS was used for simulations, whose results were found to be consistent with those of the experiments. This paper describes a method for determining the safety of soil and piles with peel damage at different temperatures, and it also provides a validation of the necessity of holding the rest constant.

The Efficacy of Electromechanical Impedance Monitoring of Embedded Piezoelectric Ceramic Lead Zirconium Titanate Sensors in Different Orientations for Hybrid Fiber-Reinforced Concrete Structures Hydration

Abstract In this study, the influence of the orientation of embedded piezoelectric ceramic lead zirconium titanate (PZT) on the mechanical performance of hybrid fiber-reinforced (polypropylene and glass fiber) concrete beams was evaluated. The performance of concrete was evaluated under self-weight, followed by assessing the mechanical property using the electromechanical impedance (EMI) technique after optimization of M30 grade concrete with polypropylene fiber and glass fiber. PZT patches are embedded at different orientations, i.e., 0 deg, 45 deg, and 90 deg, with the axis of the structure for monitoring the hydration of the RC beam. The change in stiffness due to heat hydration in the concrete structure after 5, 7, 14, 21, and 28 days was observed by curing hybrid concrete beams and examining them after 5, 7, 14, 21, and 28 days. On the fifth day, beams were simply supported and allowed to deflect under their weight, and measurements of heat hydration in terms of conductance at frequencies ranging between 1 and 1000 kHz were done. Similarly, days 7, 14, 21, and 28 were done. Day 5 was considered the baseline. It is noted that the PZT sensor placed at an angle of 45 deg is the least effective in recording the incremental changes in hydration that occurred in the concrete beam. The highest quality results were obtained at 90 deg, which is further demonstrated by statistically quantifying the changes using the root-mean-square deviation (RMSD) percentage method and proves to be the most optimized orientation to obtain the stiffness of the hybrid reinforced beam in terms of conductance.

Research on an Intelligent Piezoelectric Needle Selector System with Closed-Loop Fault Detection Capability

The piezoelectric needle selector is a crucial component of computerized dobby weft knitting machines. With the continuous development of weft knitting machine technology, enhancing the accuracy of piezoelectric needle selector control is essential. Accurate determination of whether the blades are in the correct position would significantly improve the precision of piezoelectric needle selector control. In this study, piezoelectric ceramic sensors were used to collect impact vibration signals when the blades struck the damper baffle. Key hardware circuits were designed for this purpose. A self-learning algorithm was employed to capture the highest point and the time it takes to reach the highest point in the impact vibration signal. A fault detection algorithm was used to implement closed-loop fault detection for piezoelectric needle selectors. Experimental results and practical applications have demonstrated that this research effectively addresses the accurate determination of whether the piezoelectric needle selector blades are in the correct position. It has reduced the defect rate of fabric production in weft knitting, thereby improving the overall efficiency and profitability of businesses.

Active Vibration Control Using Loudspeaker-Based Inertial Actuator with Integrated Piezoelectric Sensor

With the evolution of the aerospace industry, structures have become larger and more complex. These structures exhibit significant characteristics such as extensive flexibility, low natural frequencies, numerous modes, and minimal structural damping. Without implementing vibration control measures, the risk of premature structural fatigue failure becomes imminent. In present times, the installation of inertial actuators and control signal acquisition units typically requires independent setups, which can be cumbersome for practical engineering purposes. To address this issue, this study introduces a novel approach: an independent control unit combining a loudspeaker-based inertial actuator (LBIA) with an integrated piezoelectric ceramic sensor. This unit enables autonomous vibration control, offering the advantages of ease of use, low cost, and lightweight construction. Experimental verification was performed to assess the mechanical properties of the LBIA. Additionally, a mathematical model for the LBIA with an integrated piezoelectric ceramic sensor was developed, and its efficacy as a control unit for thin plate structure vibration control was experimentally validated, showing close agreement with numerical results. Furthermore, the LBIA’s benefits as an actuator for low-frequency mode control were verified through experiments using external sensors. To further enhance control effectiveness, a mathematical model of the strain differential feedback controller based on multi-bandpass filtering velocity improvement was established and validated through experiments on the clamp–clamp thin plate structure. The experimental results demonstrate that the designed LBIA effectively reduces vibration in low-frequency bands, achieving vibration energy suppression of up to 12.3 dB and 23.6 dB for the first and second modes, respectively. Moreover, the LBIA completely suppresses the vibration of the fourth mode. Additionally, the improved control algorithm, employing bandpass filtering, enhances the effectiveness of the LBIA-integrated sensor, enabling accurate multimodal damping control of the structure’s vibrations for specified modes.

Extraction of Heartbeat Feature Based on Ballistocardiogram Signal From Multichannel Piezoelectric Ceramic Sensors

Extraction of Heartbeat Feature Based on Ballistocardiogram Signal From Multichannel Piezoelectric Ceramic Sensors

Piezoelectric ceramic sensor-based structural health monitoring of diagonally braced H-shaped steel structures

In this study, we propose a piezoelectric ceramic sensor-based health monitoring method to monitor the stress state of diagonally braced H-shaped steel structures. Loading experiments were carried out on diagonally braced H-shaped steel under different working conditions. Subsequently, the amplitude and energy of piezoelectric signals under these two working conditions were compared and analyzed, and finite element analysis was performed using ABAQUS software to verify the results. The experimental results showed that with an increase in the web height or load, the time-domain waveform energy index of the H-shaped steel increased. Under different working conditions, such as a diagonally braced H-shaped steel member with a web height of 10 cm, when the pressure value was less than 10 N/mm2, the energy index increased by approximately 15.98% for every 1 N/mm2 increase in the pressure. When the pressure value was greater than 10 N/mm2 and less than 15 N/mm2, the energy index increased by approximately 1% for every 1 N/mm2 increase in pressure. Further, the energy index increased by approximately 8.4% for every 1 cm increase in the height of the web. Simultaneously, it can be seen from the results of the finite element analysis that the stress and strain at the induction position of the piezoelectric ceramic sensor increased with an increase in the external pressure. The study of structural health monitoring for diagonally braced H-shaped steel structures holds significant importance in ensuring the safety and reliability of these structures, achieving predictive maintenance, evaluating structural performance and energy efficiency, and optimizing structural maintenance.

Study on pile-soil bonding condition based on transient shock response using piezoceramic sensors

The field evaluation of pile-soil combination is a key step in the service life evaluation of pile foundation. However, due to the time-varying nature of pile-soil interaction, there is no efficient method to accurately analyze it. This paper introduces a health monitoring technique for assessing the state of pile-soil bond. The transient vibration of pile-soil coupling was measured by piezoelectric ceramic sensor. In the experiment, the different bond states of pile and soil were simulated by taking clay of different density as an example. A horizontal force is applied to the top of the pile, and the induced stress wave is detected by piezoelectric ceramic intelligent aggregate sensor embedded in the pile. At the same time, taking the artificial separation of pile-soil as an example, the binding state of pile-soil is analyzed, and the influence of different soil conditions on the pile-soil bonding characteristics is studied. An energy index for quantitative evaluation of pile-soil binding quality is proposed. Taking piles buried in two layers of soil with different densities as an example, the effects of soil with different densities on pile-soil bonding characteristics were studied. Experimental and numerical results verified the effectiveness of the proposed method. The three factors influenced the pile-soil coupling. The experimental and numerical results verified the effectiveness of the proposed approach and pave the way for an approach to directly judge whether there is separation between the pile and soil and evaluate the pile safety.

Monitoring Corrosion of Steel Bar in Concrete Using Ultrasonic Wave

The problem of steel corrosion in reinforced concrete structure is very serious. The purpose of this paper is to monitor steel corrosion by ultrasonic guided wave. Ultrasonic guided wave monitoring is a kind of dynamic nondestructive testing technology, which has the advantages of real-time, on-line and continuous. In this paper, an ultrasonic in-situ monitoring technique of steel bar corrosion based on embedded piezoelectric ceramic sensor is introduced. Based on this, ultrasonic guided wave was used to monitor mortar samples with different strengths of uniform corrosion, and scanning electron microscopy was used to observe the interface between reinforcement and concrete at different corrosion stages. The results show that the variation trend of ultrasonic guided wave amplitude can reflect the degree of corrosion. Mortar with different strength will affect the time and trend of corrosion. The scanning electron microscopy (SEM) method shows that the changing process of the interface between reinforcement and concrete is consistent with the trend of ultrasonic guided wave.

Monitoring and Analysis of the Collapse Process in Blasting Demolition of Tall Reinforced Concrete Chimneys.

Aiming at the problem of displacement of collapse direction caused by the impact of the high-rise reinforced concrete chimney in the process of blasting demolition, combined with the monitoring methods such as high-speed photography observation, piezoelectric ceramic sensor, and blasting vibration monitor, the impact process of the 180 m high chimney was comprehensively analyzed. The results show that the chimney will experience multiple 'weight loss' and 'overweight' effects during the sit-down process, inducing compressive stress waves in the chimney. When the sit-down displacement is large, the broken reinforced concrete at the bottom can play a significant buffering effect, and the 'overweight' effect gradually weakens until the sit-down stops. The stress of the inner and outer sides of the chimney wall is obviously different in the process of collapsing and touching the ground. The waveform of the monitoring point of the piezoelectric ceramic sensor is divided into three stages, which specifically characterizes the evolution process of the explosion load and the impact of the chimney. The vibration induced by explosive explosion is mainly high-frequency vibration above 50 Hz, the vibration induced by chimney collapse is mainly low-frequency vibration below 10 Hz, and the vibration characteristics are obviously different. In the process of blasting demolition and collapse of high-rise reinforced concrete chimney, due to the impact of sitting down, the wall of the support tube is subjected to uneven force, resulting in the deviation of the collapse direction. In practical engineering, the control measures of chimney impact, blasting vibration, and collapse touchdown vibration should be fully strengthened to ensure the safety of the protection target around the blasting demolition object.

Monitoring of the Bond State between the Concrete-Filled Steel Tube Pile and Surrounding Soil

The bonding state of the pile-soil interaction is complex. Traditional monitoring methods and tools have not been fully applied to monitor and evaluate it although it affects the lifecycle safety of the pile. In this study, a health monitoring method is proposed to evaluate the bonding state of the pile-soil contact area; it is a transient impact response method based on piezoelectric ceramic sensors to monitor the pile-soil bonding state. During the test, different damage degrees of the pile-soil bonding state were simulated by considering the working conditions of different soil densities and different crack depths as examples. A horizontal transient impact stress was applied to the pile top, and a piezoelectric ceramic sensor embedded in the pile detected the stress wave. As the stress wave response differs in different damage conditions, an energy index was established to quantitatively monitor the degree of damage.

Experimental Verification and Analysis of Vibration Damping Structure of Piezoelectric Ceramic Grain Loss Sensor

In this study, in order to achieve accurate detection of grain loss during the process of combine harvester harvesting, a piezoelectric-based grain loss sensor has been developed. The sensor utilizes a double-layer circular piezoelectric ceramic sheet as its sensitive element. When different grains come into contact with the sensitive element, the piezoelectric effect of the ceramic sheet generates corresponding charges. These charges are then converted into knock charge signals through a charge amplification signal processing circuit that has been specially designed for this purpose. The harsh operating conditions of the sensor, including the presence of significant vibration and noise interference, necessitate the incorporation of a double-layer vibration-damping structure in both the top and bottom layers of the sensor. This paper seeks to analyze the vibration-damping effect of various shock-absorbing materials and structures incorporated into the sensor. This is accomplished by creating a dynamic analysis model that accounts for vibration interference. Furthermore, an experimental bench is established for the purpose of verifying the vibration-damping test results. These tests demonstrate that the utilization of a properly selected vibration-damping structure and materials can effectively eliminate mechanical vibration and noise interference. This, in turn, leads to improved detection accuracy of charge signals after knocking and enhances the overall anti-interference ability of the sensor.

Development and Temperature Correction of Piezoelectric Ceramic Sensor for Traffic Weighing-In-Motion.

Weighing-In-Motion (WIM) technology is one of the main tools for pavement management. It can accurately describe the traffic situation on the road and minimize overload problems. WIM sensors are the core elements of the WIM system. The excellent basic performance of WIMs sensor and its ability to maintain a stable output under different temperature environments are critical to the entire process of WIM. In this study, a WIM sensor was developed, which adopted a PZT-5H piezoelectric ceramic and integrated a temperature probe into the sensor. The designed WIM sensor has the advantages of having a small size, simple structure, high sensitivity, and low cost. A sine loading test was designed to test the basic performance of the piezoelectric sensor by using amplitude scanning and frequency scanning. The test results indicated that the piezoelectric sensor exhibits a clear linear relationship between input load and output voltage under constant environmental temperature. The linear correlation coefficient R2 of the fitting line is up to 0.999, and the sensitivity is 4.04858 mV/N at a loading frequency of 2 Hz at room temperature. The sensor has good frequency-independent characteristics. However, the temperature has a significant impact on it. Therefore, the output performance of the piezoelectric ceramic sensor is stabilized under different temperature conditions by using a multivariate nonlinear fitting algorithm for temperature compensation. The fitting result R2 is 0.9686, the root mean square error (RMSE) is 0.2497, and temperature correction was achieved. This study has significant implications for the application of piezoelectric ceramic sensors in road WIM systems.

Freeze–thaw process of soil between two piles as monitored by piezoelectric ceramic sensor

As the mechanical properties of soil are affected by the moisture content, diameter of soil particles, and the soil temperature, we used piezoelectric ceramic sensors to monitor the freeze–thaw cycle of different soils at different temperatures and different moisture content. By studying the energy attenuation of stress waves propagating in freezing–thawing soil, its mechanical strength was determined. The results showed that the duration of freeze–thaw process was related to soil type and initial water content. For the same water content and larger soil particle size, the received signal amplitude and energy are larger. For the same soil type and higher water content, the received signal amplitude and energy are stronger. This study provides a feasible monitoring method for infrastructure construction in areas with complex geological conditions, such as Qinghai-Tibet frozen soil.

Numerical and experimental study on monitoring coal cracks with PZT sensor

The rupture of coal pillar can lead to spontaneous combustion or collapse of goaf, which endangers the safety of workers. To explore the relationship between the crack depth of the coal structure and the signal received by the piezoelectric ceramic sensor, the output data of coal samples were analyzed by using the piezoelectric effect, combined with the experiment and ABAQUS simulation. Based on the signal amplitude, the output signal characteristics of the coal model with different crack depths were analyzed, and the evaluation index of coal crack cracking degree (Dc) was defined. The results show that the piezoelectric fluctuation method can effectively identify the local cracks of coal. When the distance between the lead Piezoelectric Transducer (PZT) patch and crack position is constant, the amplitude of the PZT patch output signal will decay with the deepening of the crack depth, while the value of increases with the increase of crack depth. This study provides a theoretical basis for mine disaster prevention and control.

Damage imaging method for composites laminates based on sparse reconstruction of single-mode Lamb wave

To address the problems of anisotropy and mode mixing in damage imaging on anisotropic composites laminates using ultrasonic Lamb wave, a sparse reconstruction imaging method based on S0 single-mode is proposed in this paper. In this approach, the sparsely arranged piezoelectric ceramic drivers sensor group on the surface of the measured composite laminate is employed to excite and receive Lamb wave. The received signal shows sparse under a pre-built damage dictionary with damage scattering signal waveform, and the damages can be localized and imaged using a sparse reconstruction method. Considering the velocity difference between S0 and A0 mode of the received Lamb wave signal, the S0 mode is extracted by intercepting the signal before the peak of the first wave packet to eliminate the influence of Lamb wave mode mixing. In order to minimize the influence of anisotropy of composites laminates on Lamb wave propagation, the Lamb wave propagation direction is divided evenly into several sectors, and Lamb wave propagation direction within a certain sector is considered as propagation in a quasi-isotropic material. The sparse reconstruction is solved by using the basis pursuit de-noising algorithm, which can find the optimal solution with a small number of iterations in noise interference. The experiments on composite fiber laminate specimens show that the proposed method can accurately locate simulated single delamination damage and has less artifact interference compared to the delay-and-sum method.