This paper presents the design, fabrication, and testing of a dual-resonance acoustic emission (AE) sensor based on PMN-PT single crystal for partial discharge (PD) detection. The use of ...high-performance PMN-PT single crystal enhances the sensor sensitivity. Resonance peak coupling is utilized to increase the bandwidth of the sensor effectively. The effects of piezoelectric vibrator size, vibrator spacing, and external circuitry on the sensor output are analyzed using equivalent circuits and finite element models (FEM) for sensor design. After calibration, the self-made sensor has a peak sensitivity of 76.4 dB and a bandwidth of 20 kHz to 150 kHz, which meets the demand of PD detection. The PD detection experiments verify that the self-made sensors can accurately detect PD with a high signal-to-noise ratio of 15.8 dB. In the end, the reliability test proves that the sensors have good stability and temperature characteristics. Besides above sensor’s performance improvement, our design has the great potential to reduce the sensor’s cross section, resulting better suitability on curved surfaces. The feasibility of employing PMN-PT as a replacement for PZT in the fabrication of AE sensors is proven by these good test results.
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•Utilize high-performance PMN-PT single crystal to enhance sensor sensitivity to 76.4 dB.•Employ resonance peak coupling to expand the sensor bandwidth, covering 20 kHz to 150 kHz.•Devise an original matching layer design method for low-frequency, wide-bandwidth applications.•Homemade sensors achieve high reliability and can detect partial discharge accurately with higher SNR.
Alternating magnetic fields generated by ac power lines are renewable energy sources that can be scavenged by magnetic energy harvesting cores for wireless sensor networks (WSNs). However, ...traditional magnetic cores are suffering from low efficiency when applied to three-core cables. This paper systematically analyzed the characteristics of the magnetic induction intensity of a three-core cable by finite element methods (FEM), figured out the optimal energy harvesting position, innovatively designed and fabricated a novel notched ring core (NNRC) to better match the magnetic field characteristics of three-core cables. Compared with the previously reported core, the NNRC has 2.3 times the output voltage per turn and more space allowance for winding coil. According to experimental results, the open-circuit output voltage amplitude of NNRC was 16.6V with 9000turns of wire and 100AAMP ac current in each phase of the cable. Finally, a non-controlled AC/DC circuit was applied and 28.4mW maximum dc power was obtained.
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•Magnetic field characteristics of three-core cables were analyzed systematically.•A high-efficiency but cost-effective energy harvesting core was designed.•The newly designed core can be used for both unarmored and armored cables.
Langasite (LGS)-based surface acoustic wave (SAW) pressure sensors have been extensively validated as a promising solution for high-temperature applications. However, mainly the Rayleigh mode SAW has ...been employed in previous research on LGS membrane-based pressure sensors. In this study, shear horizontal mode SAW (SH-SAW) is employed for its higher normalized pressure sensitivity (NPS) and bigger electromechanical coupling coefficient (<inline-formula> <tex-math notation="LaTeX">{K}^{{2}} </tex-math></inline-formula>) than the Rayleigh wave. To comprehensively calculate the SAW properties of rotated Y-cut LGS, a novel weak-form nonlinear finite element method (FEM) simulation model is applied so that the nonlinear electroelastic wave equations with reduced symmetry can be solved by the commercial FEM software directly. Meanwhile, absolute pressure sensors are fabricated and characterized on one of the well-selected optimal pressure-sensitive cuts with Euler angles of (0°, 0°, 90°). The NPS is 9.14 ppm/MPa at room temperature (RT) and 9.63 ppm/MPa at 400°C, resulting in a total variation of 4.9%. The NPS achieved by the SH-SAW-based sensor surpasses previous research findings and is consistent with simulation results. In addition, prototypes of differential pressure sensors with temperature compensation have been developed as well. The pressure sensitivity reaches a maximum of 435 ppm/MPa with a thinned membrane. Furthermore, a SiO2 cladding layer has been demonstrated to exhibit exceptional device protection and remarkable manipulation of temperature characteristics. This study demonstrates the evident enhancement of SAW pressure sensor performance through SH-SAW utilization, providing valuable guidance for future optimization of SAW sensors.
Reliable matching between the crane hook and ladle lug is a key requirement for the safe hoisting of a ladle in steelmaking. A novel method is proposed to detect the matching between the hook and lug ...using surface acoustic wave radio frequency identification (SAW RFID) localization. SAW RFID tags are attached to the surface of the lug and the hook. The position of the lug is estimated via a geometric mapping approach with a special position of the tag and the reader's antenna, and the position of the hook is estimated by a synthetic aperture approach with the hook's movement pattern. Afterwards, the matching judgement is determined based on the relative position between the hook and lug. The proposed method employs only two SAW tags and two reader antennas, facilitating installation and routine maintenance. Numerical simulation and physical experiments demonstrate that the proposed method works effectively for matching detection.
To identify buried assets, this article presents a novel design of surface acoustic wave (SAW) tag to enhance its underground penetration capacity. A penetration depth model for a SAW tag buried in ...materials is established to investigate the depth of detection and guide the design of the SAW tag. Multipulse position with all reflectors in two groups (MPP-ART) coding scheme is proposed to reduce the insertion loss of the SAW chip. A novel embedded monopole microstrip tag antenna is investigated with a stable frequency performance when embedded in diverse types of materials. Furthermore, a linear frequency modulation pulse compression transceiver based on software defined radio is implemented to enhance the penetration depth. The insertion loss of the SAW chip at 920 MHz with the MPP-ART coding scheme, is reduced to 26.58 dB. Through experiments, the penetration depth of the SAW radio frequency identification prototype has reached 0.75 m in river water, 0.8 m in tap water, 1.5 m in wet sand, and 3 m in dry sand, respectively. The experimental results demonstrate that the SAW tag can work in various materials with good penetration depth, relatively immune to electromagnetic interference with adjacent metallic objects, making it suitable for the identification of buried assets for industrial applications.
The resolution of phase difference ambiguity is critically important for simultaneously achieving wide range and high accuracy sensing with surface acoustic wave (SAW) reflective delay-line sensors. ...A novel scheme called dual-frequency interrogation and hierarchical evaluation (DFI-HE) is proposed to resolve integer ambiguity of phase difference and obtain precise time delay between reflectors. With DFI-HE, only two reflectors are needed as the sensing elements for SAW reflective delay-line sensors. Additionally, DFI-HE has the advantage of fast ambiguity resolution to enable both a wide range and high accuracy sensing. The basic principle of sensing with DFI-HE is elaborated, and simulations and temperature sensing experiments are carried out to verify the proposed scheme, based on a SAW reflective delay-line temperature sensor with two reflectors fabricated on 128° YX-LiNbO 3 substrate. The experimental results demonstrate that the temperature measurement accuracy reaches ±2 °C in the range of 8 °C-300 °C.
SAW RFID with enhanced penetration depth Xupeng Zhao; Ruchuan Shi; Yang Yang ...
2017 IEEE International Ultrasonics Symposium (IUS),
2017-Sept.
Conference Proceeding
Some methods to enhance penetration depth further are proposed and demonstrated. A second harmonics SPUDT, new criterion of matching and high reflectivity reflector are utilized to reduce the losses ...of SAW tag. The enhancement of reading system including high signal processing gain and compensate the center frequency mismatch between reader and SAW tag are achieved. Furthermore, the effect of decreasing working frequency to penetration capability is demonstrated. Mediums such as dry sandy, dry soil and water are compared in the experiments in order to get the achievable penetration depth. In conclusion, the practical penetration depth is superior to the ground penetrating radar with the same center frequency range.
It is increasingly urgent to improve the intelligent level of the equipment management for modern international airports. This is the first attempt of SAW RFID on aerodrome lights. SAW tag with ...temperature sensing function and anti-metal patch antennas are designed. The position of the tag fixed in different kinds of lights such as the runway light and the taxiway light is demonstrated. The experimental results show that SAW RFID has been successfully applied to the inspection management of aerodrome light.
SAW RFID with enhanced penetration depth Xupeng Zhao; Ruchuan Shi; Peng Qin ...
2017 IEEE International Ultrasonics Symposium (IUS),
2017-Sept.
Conference Proceeding
Construction of smart city has become a historical trend in the world. The management of underground pipes and the intelligent concrete are the main part of building smart city in China. Compared ...with the available electronic marker system, SAW-RFID system has shown excellent properties: truly passive, strong penetrating capability, long service-life, sensing and ID integration, and etc. Thus, SAW-RFID system is particularly applicable and has excellent application prospects. However, in practical implementation, the limitation of detection depth has become an obstacle on the application of SAW-RFID for the smart city in the future. Some methods to enhance penetration depth further are proposed.
Surface acoustic wave (SAW) voltage sensors merely based on piezoelectric deformation used to being applied with a scale of volts to kilovolts resolution. Combined with acoustoelectric (AE) effect, ...the SAW voltage sensor meets a new opportunity for development because both acoustic phase velocity and piezoelectric deformation are sufficiently utilized to modulate oscillation frequency. The intensity of acoustoelectric effect depends on the piezoelectric coupling and carrier mobility so the combination of lamb wave mode with electromechanical coupling coefficient (K 2 ) one order of magnitude higher than traditional SAW mode and 2D material with high carrier mobility would support a meaningful breakthrough. The resolution of acoustoelectric voltage sensor would be improved to a millivolt range.This paper will derive an acoustoelectric coupling model behind the AE voltage sensor, based on which a novel embodiment of graphene-LiNbO 3 film composite structure lamb wave voltage sensor is designed. Aiming at large K 2 and high carrier drift velocity, the device structure and parameters are optimized. The simulation results show that the relative acoustic velocity shift achieves 1‰ when the input voltage equals 8mV. This effect could not only sense millivolt voltage but also lead to a low power consumption and voltage-controlled velocity shifter. Millivolt voltage signal transmission via an acoustic resonator will be feasible too.
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