Detection Of Ultrasonic Waves Research Articles

An in situ prepared fiber-based piezoresistive film for ultrasonic wave detection on nonplanar carbon fiber-reinforced composites

Owing to the flexibility and high-frequency responsiveness, nanocomposite piezoresistive sensors are suitable for Lamb wave detection on composite materials. Various types of nanocomposite films have been developed for this purpose. However, the inelasticity trait of commonly used electrodes for the nanocomposite films impedes their application on the nonplanar surface of composites. Herein, an in situ prepared piezoresistive film based on graphene and polymethyl methacrylate nanocomposite has been proposed for ultrasonic wave detection on nonplanar carbon fiber-reinforced composites. Electrospinning method is employed to fabricate piezoresistive fiber film onto carbon fiber-reinforced polymer (CFRP) composites, and the sensitivity along the thickness direction is utilized via employing the CFRP layer as one electrode. The fabricated sensitive films exhibit the capability to detect up to 150 kHz ultrasonic signals on curved surfaces. With the help of Hilbert energy spectrum, the precise damage localization on CFRP is achieved by the sensitive film array with a relative error of only 1%. This innovation provides a new in situ preparation method for ultrasonic sensitive film on nonplanar-shaped CFRP components for nondestructive evaluation task.

Subsurface defect detection of high-temperatured components with laser induced surface wave

Abstract Subsurface defects are detrimental to the safety and integrity of critical components in various fields, particularly for those used in high-temperature environments. For this reason, a reliable non-destructive evaluation (NDE) method for in-situ inspection of subsurface defects of high-temperatured components is highly desired. Laser ultrasonic technique offers a promising potential to accommodate the demands in virtue of non-contact generation and detection of ultrasonic waves. In this work, laser ultrasosnic inspection of subsurface defects in high-temperatured components is proposed, which exploits the modal conversion of surface longitudinal wave to Rayleigh wave. The modal conversion was firstly investigated with finite element simulation, from which the phenomenon of modal conversion can be readily identified. Thereafter, an experimental setup is built to verify the feasibility and effectiveness of proposed method. Notably, a delay-and-sum method based on a scanning procedure is conducted to coherently increase the detection sensitivity of subsurface defects, since the surface longitudinal wave rapidly vanishes with propagation distance., and the temperature-dependant velocity variation can be adaptively compensated. This work provides a viable route for in-situ inspection of subsurface defects in high-temperatured components where conventional ultrasonic method fails, and it would find potential applications in broad fields, such as coating quality evaluation in fabrication, bearing assessment under load, and in-situ monitoring for additive manufacturing.

Efficiency analysis of laser ultrasonic longitudinal wave detection based on the constraint effect

Abstract Laser ultrasound is a non-destructive inspection technique, but its application in internal defect detection and state characterization is limited by its weak body wave displacement induced by thermo-elastic mechanism. In this paper, the influence of the constraint layer on the directivity of laser induced ultrasonic force source and the excitation efficiency of longitudinal wave is analyzed by finite element modeling with transparent glass as the constraint layer. With the optimization of the parameters of the confinement layer, the longitudinal waves with energy comparable to that of the free surface ablation mechanism can be excited under the thermoelastic mechanism, which greatly improves the efficiency of the longitudinal wave of laser ultrasonic. Applying the above research results to the detection of internal defects, the imaging results of the internal defects are obvious and the location defects are accurate.

Research on ultrasonic-electromagnetic wave simultaneous sensing sensors

Ultrasonic and electromagnetic wave detection signals are effective characterization signals for state detection, such as medical imaging, ocean exploration, and industrial applications.In order to simplify the complexity of ultrasonic and electromagnetic wave signal detection, this paper proposes a sensor design idea with both ultrasonic and electromagnetic wave sensing functions, and develops an ultrasonic-electromagnetic wave simultaneous sensing sensor based on the application scenario of ultrasonic and electromagnetic wave signal sensing requirements of discharge insulation defects of power equipment.The simulation results show that the voltage standing wave ratio of the sensor designed in this paper is less than 3.3 in the electromagnetic wave band of 0.3 GHz ∼ 3.0 GHz. The average ultrasonic sensitivity in the range of 20 kHz ∼ 80 kHz is 48 dB ( Ref 1 V / ( m / s)), and the peak sensitivity is 62 dB.Finally, the construction of power equipment discharge insulation defects simulation experimental platform, ultrasonic - electromagnetic wave simultaneous sensing sensor performance testing, the experimental results show that the sensor can be developed at the same time accurately detect the ultrasonic and electromagnetic wave signals, the results of the research in this paper will significantly reduce the application cost of ultrasonic and electromagnetic wave detection device.

Research on test method of multi-channel ultrasonic wave detection for gas well injection volume

In the early stage of natural gas extraction, the fracturing and blowout process is often used to obtain stable production. However, during the fracturing process, natural gas combustion is frequently directly released, which causes significant pollution to the environment and a waste of resources. In order to measure the flow rate of the gas-liquid mixture in the process of gas well blowout, a multi-channel velocity measurement model is established. The multi-channel sensor structure is designed based on an analysis of the gas well blowout process and fluid configuration simulations. The influence of pipe diameter on the flow characteristics of gas-liquid two-phase flow was analyzed by FLUENT software. The simulation results show that the distribution of flow velocity in a gas-liquid two-phase flow tube is not uniform, the flow velocity of different flow layers is different, and the stratification phenomenon is more obvious with the increase of pipe diameter, highlighting the necessity of multi-channel measurements. Therefore, we developed a gas-liquid two-phase flow velocity measuring device. The experimental results demonstrate that accurately describing velocity in the tube can be achieved by measuring velocities in different channels using the gas-liquid two-phase flow velocity measurement device.

An ultrasonic approach for characterising subsurface fractures in concrete

ABSTRACT An ultrasonic Rayleigh wave detection method is proposed to determine the geometrical characteristics of subsurface small-scale fractures in concrete. A three-dimensional observation system, including an inclined wedge ultrasonic device, is used to obtain the Rayleigh wave wide-angle data to exhibit the azimuth-dependent scattered wave field. The anisotropic characteristics of Rayleigh wave transmission coefficient are used to determine the distribution range and dip angle of fractures. Fracture models in concrete with different dip angles are designed, and the dip angle is correlated with the degree of attenuation (transmission coefficient) anisotropy. The transmission coefficient characteristics are presented in a random observing system. A focusing approach can be adopted to distinguish the subsurface fracture and to verify the reliability and flexibility of the surface wave approach in practice. The tendencies of experimental results are consistent with patterns obtained from numerical simulation. The proposed method has important application prospects for the non-destructive testing of complex invisible fractures in concrete.

Quantitative detection and evaluation of Rayleigh ultrasonic wave for fatigue crack on turbine blade surface

In this paper, different characteristics of micro-cracks on the surface of turbine blades have been successfully evaluated based on the detection of Rayleigh ultrasonic wave by numerical simulation and experimental study. The quantitative relationship between the maximum amplitude of Rayleigh ultrasonic wave and the features of cracks including width, depth, excitation position, and inclination angle was established. Numerical calculations of different curvature models show that curvature has no significant effect on the propagation of Rayleigh ultrasonic wave. According to the developed multi-functional ultrasonic equipment, cracks on complex surfaces can be detected by clamping two probes on the arc guide rail. The experimental results verify the validity of the numerical simulations. It gives an excellent basis for the effective automatic detection of cracks on the surface of turbine blades. This research provides a suitable method and new equipment for rapid quantitative inspection of turbine blades.

3D printed triboelectric nanogenerator for underwater ultrasonic sensing

The underwater ultrasound power measurement has become necessary due to the rapid development of sonochemistry and sonocatalysis. This article presents construction of novel triboelectric nanogenerator (TENG) and its application for a detection of ultrasonic waves in water. The device was 3D printed using widely available and cost-effective materials. TENG consisted of the device housing and movable polymer pellets confined between flat electrodes. The device housing and pellets were 3D printed via stereolithography (SLA) and fused deposition modelling (FDM) methods, respectively. The pellets moved periodically driven by the ultrasonic waves leading to generation of an alternating voltage signal. The electric response of TENG was calibrated using a commercially available ultrasonic power sensor. The open-circuit voltage output of TENG was registered in different sections of the ultrasonic bath in order to determine the distribution of the acoustic power. TENG electric responses were analyzed by applying the fast Fourier transform (FFT) and fitting the theoretical dependence to experimental data. The main peaks in the frequency spectra of the voltage waveforms corresponded to the fundamental excitation frequency of the ultrasonic bath. TENG device, presented in this paper, can be successfully applied as a self-powered sensor for detection of ultrasonic waves. It enables precise control of the sonochemical process and reduction of power losses of the ultrasonic reactor. 3D printing technology has been confirmed to be fast, easy, and scalable method of fabrication of the ultrasonic sensors.

Time-of-Flight measurement on a rail by laser-ultrasound

Stress states of thermal origin on the Continuously Welded Rail (CWR) are a source of possible inconvenience due to winter breakage or dangerous summer buckling. To date, alongside procedures based on the measurement of rail displacements or rail cutting, several methods for measuring the stress state in the rail have been proposed, based on X-ray diffraction, Barkhausen noise, and the acoustoelastic effect; all these approaches have some critical issues for extensive use in the field. The acoustoelastic method is based on the dependence of the ultrasonic wave speed on the stress state of the material and involves the measurement of the Time of Flight (ToF). Because of the modest acoustoelastic effect, the speed variations caused by the stress states are very limited, which is reflected in the need for ToF measurements with an accuracy of the order of a few nanoseconds.In the past, the research group successfully used the acoustoelastic method to monitor a 3 km portion of a rail between Florence and Pontassieve, with fixed measurement stations, where the ultrasonic probes were permanently positioned on the neutral axis of the rail. Today, the need is to have a mobile measuring system, which can measure in several points or even continuously as the system moves along the rail. This appears to be possible through the use of, for example, non-contact systems such as those based on laser and air-coupled probes or lasers alone. In the first case, however, the acoustic wave partly propagates in the air before reaching the piezoelectric probe, and this path is subjected to variations in temperature and thus ToF. In the second case, the ultrasonic waves are generated and detected by optical methods with lasers. For the generation of acoustic waves, the use of pulsed lasers has become a widespread, reliable practice, which allows researchers to obtain signals of high amplitude and wide bandwidth. For the reception of the acoustic signal, the precision required in the measurement involves careful analysis and experimentation to identify the most appropriate laser technique, depending on the quality of the surface on which the measurement is performed, the sensitivity of the method, and the possibility of taking measurements while moving.In the present work, a technique for laser detection of ultrasonic waves, Optical Beam Deflection (OBD), is analysed. The technique is based on the deflection of an optical beam: the beam irradiates the surface of the rail and is reflected at angles that depend on the orientation of the surface at the point of measurement, which is perturbed by the passage of the acoustic wave. The technique, developed in the 1990s, has limited applications in non-destructive testing, where interferometer-based techniques are more widespread; still, they require more sophisticated and expensive equipment. Different experimental arrangements and initial experimental results are analysed and presented, to optimise their sensitivity and verify their suitability for the purpose.

In Situ Optical Detection for Ultrasonic Characterization of Materials in a Mach 10 Hypersonic Wind Tunnel

We present results of in situ optical detection of ultrasonic waves generated in stainless steel and graphite samples mounted in a flat plate model during hypersonic flow in the 31-Inch Mach 10 wind tunnel at NASA Langley Research Center. Longitudinal waves are excited in the stainless steel and graphite sample inserts by using a contact piezoelectric transducer and the normal displacement on the surface of the sample, exposed to hypersonic fluid flow, is measured optically using a Sagnac interferometer. Measurements are consistent at different Reynolds numbers both with and without a turbulent trip strip present. Additionally, optical detection of laser-generated surface acoustic waves in a stainless-steel sample during flow is presented. These results are a demonstration of laser-based ultrasonics as an in situ material characterization technique in hypersonic flow, enabling potential applications of in situ monitoring of defect initialization and morphology in hypersonic environments.

A self-powered acoustic sensor excited by ultrasonic wave for detecting and locating underwater ultrasonic sources

Triboelectric nanogenerators (TENGs) have great potential for utilizing acoustic energy. However, as for the ultrasonic source, the high frequency vibration may aggravate mechanical wear and weaken the stability of the TENG device. Meanwhile, the reported complicated structure design and fabrication greatly hinder the development of TENG for ultrasonic energy harvesting. In this study, we find an interesting phenomenon that perfluorinated polymer film under sonication can be separated from its attached adhesive. Based on this ultrasound-induced separation, an easy-fabricated and compact-structured ultrasound-driven TENG (UD-TENG) is proposed to harvest ultrasonic energy in a facile way. The mechanism of the coupling between weak adhesion of perfluorinated polymer film and ultra-high ultrasonic pressure verified by simulation and experiment is investigated. The relationship between the surface energy and the film-adhesive separation force is determined by comparing different films. Furthermore, the intensity and direction of ultrasound further reveals the effect of ultrasound parameters on UD-TENG’s output performance. UD-TENG can achieve high charging rate of 75 μC/s and exhibit excellent stability with no obvious attenuation of the voltage signal after sonicating for 1 h. A series of practical devices driven by the UD-TENG serving as power supplier are demonstrated. Finally, a self-powered acoustic sensor which can collect ultrasonic signal from multiple angles is developed for underwater ultrasonic wave detection and sound source location. This work provides a new guidance for the study of harvesting ultrasonic energy and expands the underwater applicability of TENGs.

3D-Printable Piezoelectric Composite Sensors for Acoustically Adapted Guided Ultrasonic Wave Detection.

Commercially available photopolymer resins can be combined with lead zirconate titanate (PZT) micrometer size piezoelectric particles to form 3D-printable suspensions that solidify under UV light. This in turn makes it possible to realize various non-standard sensor geometries which might bring benefits, such as increased piezoelectric output in specific conditions and less interference with incoming waves due to better acoustical adaptation compared to solid PZT ceramics. However, it is unclear whether piezoelectric composite materials are suitable for guided ultrasonic wave (GUW) detection, which is crucial for structural health monitoring (SHM) in different applications. In this study, thin piezoelectric composite sensors are tape casted, solidified under UV light, covered with electrodes, polarized in a high electric field and adhesively bonded onto an isotropic aluminum waveguide. This approach helps to demonstrate the capabilities of tape casting’s freedom to manufacture geometrically differently shaped, thin piezoelectric composite sensors for GUW detection. In an experimental study, thin two-dimensional piezoelectric composite sensors demonstrate successful detection of GUW for frequency-thickness products of up to 0.5 MHz mm. An analytical calculation of the maximum and minimum amplitudes for the ratio of the wavelength and the sensor length in wave propagation direction shows good agreement with the sensor-recorded signals. The output of the piezoelectric composite sensors and occurring reflections as measure for wave interactions are compared to commercial piezoelectric discs to evaluate their performance.

Insights into Metal Sheet Novelty Detection via Simulated Electromagnetic Ultrasonic Surface Wave

Metal sheets have good performance and have been widely used. Different kinds of defects can be generated during the preparation and service of metal plates, which will cause the structural performance of the metal plates to decline, thus requiring structural health monitoring (SHM). This study proposes an electromagnetic ultrasonic (EMUS) surface wave detection technique for metal sheet defects via simulation. The numerical results show that after the excitation parameters of the EMUS transducer are optimized through orthogonal experimental design, the amplitude of the EMUS signal generated is increased by about 80%. The power spectrum density (PSD) of the EMUS response signal is used to detect defects. Compared with the peak-to-peak detection, the accuracy is higher, and the reliability is better. The accuracy of the proposed “central zero-point” method for measuring the time delay of the EMUS signal wave packet is higher than that of the “peak-to-peak amplitude” method and the “vibration starting point” method and is close to the accuracy of the “cross-correlation” method.

Assessment of the intrinsic damage to refractory materials at high temperatures using the laser ultrasonic pulse method

Refractory materials play a significant role for high temperature industrial processes. In such harsh environments occurring material damages are a challenge and their assessment is important. In this work refractory material damages have been assessed by laser ultrasonic pulse (LUP) method by investigating changes of Young's modulus and Poisson's ratio up to 1000 °C. The LUP method operates by laser ultrasonic wave generation and detection and is therefore non-contacting and non-destructive. As a consequence of material damages, the propagation velocities of the ultrasonic waves inside the materials are affected. Therefore, the elastic properties change and material damages can be determined up to a microstructural range. A broad variety of refractory ceramics were examined e.g., fused silica, alumina, andalusite and high alumina composite materials. After induced intrinsic damages by pressing and water quenching thermal shocks from 950 °C to 10 °C Young's modulus and Poisson's ratio decreased.

Variance of elastic wave scattering from randomly rough surfaces

Elastic waves scattered by randomly rough surfaces in solid media play an important role across research topics including ultrasonic wave detection and imaging, seismic wave exploration and phonon boundary interaction. Previous attention has focused upon the mean/expected scattering intensity for both compressional (P) and shear (S) waves. In this article, the variance or the standard deviation (sd) of elastic wave scattering from randomly rough surfaces is studied, which so far has been neglected despite their practical importance in elastic wave applications, via an analytical approach. Theoretical formulae are derived with the aid of the elastodynamic Kirchhoff approximation (KA), to rapidly predict the variance of the scattering amplitude and the intensity, once the statistical parameters of the roughness are known. Theoretical formulae are then successfully validated against high-fidelity Monte Carlo finite element (FE) simulations at different scattering angles across a range of roughness. With the analytical approach the effects of rms roughness, the correlation length and the surface length on the standard deviation of the scattering amplitude are analysed. The significance for applications is illustrated in one important example taken from the field of ultrasonic wave detection of planar rough defects. The theoretical formulae accurately predict the lower bound of the scattering amplitude, which helps set an amplitude threshold confidently, for detecting any possible rough crack in a single inspection while minimising the risk of false alarm. The significantly improved accuracy and confidence of detection enable reliable decisions to be made about whether it is safe to continue using an engineering component.

Analysis of Embedded Optical Interferometry in Transparent Elastic Grating for Optical Detection of Ultrasonic Waves.

In this paper, we propose a theoretical framework to explain how the transparent elastic grating structure can be employed to enhance the mechanical and optical properties for ultrasonic detection. Incident ultrasonic waves can compress the flexible material, where the change in thickness of the elastic film can be measured through an optical interferometer. Herein, the polydimethylsiloxane (PDMS) was employed in the design of a thin film grating pattern. The PDMS grating with the grating period shorter than the ultrasound wavelength allowed the ultrasound to be coupled into surface acoustic wave (SAW) mode. The grating gaps provided spaces for the PDMS grating to be compressed when the ultrasound illuminated on it. This grating pattern can provide an embedded thin film based optical interferometer through Fabry–Perot resonant modes. Several optical thin film-based technologies for ultrasonic detection were compared. The proposed elastic grating gave rise to higher sensitivity to ultrasonic detection than a surface plasmon resonance-based sensor, a uniform PDMS thin film, a PDMS sensor with shearing interference, and a conventional Fabry–Perot-based sensor. The PDMS grating achieved the enhancement of sensitivity up to 1.3 × 10−5 Pa−1 and figure of merit of 1.4 × 10−5 Pa−1 which were higher than those of conventional Fabry–Perot structure by 7 times and 4 times, respectively.

Bone Chemical Composition Analysis Using Photoacoustic Technique

Photoacoustic (PA) signal analysis based on ultrasonic wave detection can provide both high-sensitivity optical contrast information and micro-architectural information which is highly related with the chemical composition of tissue. In this study, the feasibility assessment of bone composition assessment was investigated using the multi-wavelength PA analysis (MWPA) method which could reflect the molecular information. By illuminating a bone specimen using a laser light with wavelength over an optical spectrum ranging from 680 to 950 nm, the optical absorption spectrum of the bone was acquired. Then, with the optical absorption spectra of all optical absorption chemical components in the known bone, a spectral unmixing procedure was performed to quantitatively assess the relative content of each chemical component. The experimental results from rabbit bones show that MWPA method can be used to assess chemical components related to bone metabolism. Our study confirmed that PA technique can be used as a novel bone diagnostic technique by providing new information about the quantity of bone and identifying biomarkers of bone that can improve the current diagnostic imaging techniques.

Low-Cost, High-Performance Fiber Optic Fabry⁻Perot Sensor for Ultrasonic Wave Detection.

This study describes a novel fiber optic extrinsic Fabry–Perot interferometric (EFPI) ultrasonic sensor comprising a low-cost and high-performance silicon diaphragm. A vibrating diaphragm, 5 μm thick, was fabricated by using the Microelectromechanical Systems (MEMS) processing technology on a silicon-on-insulator (SOI) wafer. The Fabry–Perot (FP) cavity length was solely determined during the manufacturing process of the diaphragm by defining a specific stepped hole on the handling layer of the SOI wafer, which made the assembly of the sensor easier. In addition, the use of cheap and commercially available components and MEMS processing technology in the development of the sensing system, limited the cost of the sensor. The experimental tests showed that the minimum detectable ultrasonic pressure was 1.5 mPa/sqrt(Hz) −0.625 mPa/sqrt(Hz) between 20 kHz and 40 kHz. As a result, this sensor has the potential to successfully detect weak ultrasonic signals.

Gas Leak Location Detection Based on Data Fusion with Time Difference of Arrival and Energy Decay Using an Ultrasonic Sensor Array.

Ultrasonic gas leak location technology is based on the detection of ultrasonic waves generated by the ejection of pressured gas from leak holes in sealed containers or pipes. To obtain more accurate leak location information and determine the locations of leak holes in three-dimensional space, this paper proposes an ultrasonic leak location approach based on multi-algorithm data fusion. With the help of a planar ultrasonic sensor array, the eigenvectors of two individual algorithms, i.e., the arrival distance difference, as determined from the time difference of arrival (TDOA) location algorithm, and the ratio of arrival distances from the energy decay (ED) location algorithm, are extracted and fused to calculate the three-dimensional coordinates of leak holes. The fusion is based on an extended Kalman filter, in which the results of the individual algorithms are seen as observation values. The final system state matrix is composed of distances between the measured leak hole and the sensors. Our experiments show that, under the condition in which the pressure in the measured container is 100 kPa, and the leak hole–sensor distance is 800 mm, the maximum error of the calculated results based on the data fusion location algorithm is less than 20 mm, and the combined accuracy is better than those of the individual location algorithms.

Potassium sodium niobate (KNN)‐based lead‐free piezoelectric ceramic coatings on steel structure by thermal spray method

AbstractFor the first time, potassium sodium niobate (KNN)‐based lead‐free piezoelectric ceramic coating with strong piezoelectric response was fabricated on stainless steel substrates by thermal spray process, after introducing NiCrAlY and yttria‐stabilized zirconia (YSZ) intermediate layers. A large effective piezoelectric coefficient (d33) of 125 pm/V was obtained with the thermal‐sprayed KNN‐based ceramic coating on the steel substrates. The mechanisms of improving the structure and enhancing the properties of the KNN‐based piezoelectric ceramic coatings by introducing the intermediate layers were analyzed. Ultrasonic transducers were designed and fabricated from the KNN‐based coatings directly formed on a steel plate structure, and the feasibility for generation and detection of ultrasonic waves for structural health monitoring using the thermal‐sprayed lead‐free piezoelectric ceramic coating was demonstrated.