Ultrasonic Phased Array Research Articles

Ultrasonic Phased Array Testing and Identification of Multiple-Type Internal Defects in Carbon Fiber Reinforced Plastics Based on Convolutional Neural Network

Carbon fiber reinforced plastics inevitably develop defects such as delamination, inclusions, and impacts during manufacturing and usage, which can adversely affect their performance. Ultrasonic phased array inspection is the most effective method for conducting nondestructive testing to ensure their quality. However, the diversity of defects within carbon fiber reinforced plastics makes it challenging for the current ultrasonic phased array inspection techniques to accurately identify these defects. Therefore, this paper presents a method for the ultrasonic phased array nondestructive testing and classification of various internal defects in carbon fiber reinforced plastics based on convolutional neural networks. We prepared an ultrasonic C-scan dataset containing multiple types of internal defects, analyzed the defect features in the ultrasonic C-scan images, and established an autoencoded classifier network to recognize manufacturing defects and impact defects of varying sizes. The experiments showed that the proposed method demonstrates superior defect feature extraction capabilities and can more accurately identify both impact and manufacturing defects.

Sonogenetics is a novel antiarrhythmic mechanism.

Arrhythmia of the heart is a dangerous and potentially fatal condition. The current widely used treatment is the implantable cardioverter defibrillator (ICD), but it is invasive and affects the patient's quality of life. The sonogenetic mechanism proposed here focuses ultrasound on a cardiac tissue, controls endogenous stretch-activated Piezo1 ion channels on the focal region's cardiomyocyte sarcolemma, and restores normal heart rhythm. In contrast to anchoring the implanted ICD lead at a fixed position in the myocardium, the size and position of the ultrasound focal region can be selected dynamically by adjusting the signals of every piezoelectric chip on the ultrasonic phased array, and it allows novel and efficient defibrillations. Based on the developed interdisciplinary electro-mechanical model of sonogenetic treatment, our analysis shows that the proposed ultrasound intensity and frequency will be safe and painless for humans and well below the limits established by the U.S. Food and Drug Administration.

Non-destructive inspection of interfacial debonding in concrete-filled steel tube bridges

ABSTRACT Concrete-filled steel tube (CFST) structures are widely used in the construction of large-scale structures owing to its exceptional load-bearing capacity. However, inadequate construction quality and improper maintenance may cause debonding defects at the steel-concrete interface. Two non-destructive testing methods, i.e. the ultrasonic phased array (UPA) method and the impact acoustic method, are developed for deboning detection. A combined inspection procedure is proposed to balance the detection accuracy and efficiency, where the impact acoustic method is utilised for a rapid preliminary inspection to pinpoint the suspected debonding areas, while the UPA method is sequentially applied to accurately evaluate the debonding rates in the suspected areas. The impact acoustic method analyzes the time-frequency spectrum from the echo signals using wavelet transform, and calculates the vibration energy ratio for debonding detection. The UPA method applies the total focusing method for image reconstruction, and extracts the reflection coefficient at the steel–concrete interface for debonding evaluation. The laboratory experimental results show that the combined method possesses a high accuracy and accurately delineates the range of the debonding defect while preserving the detection efficiency. Field tests conducted on an arch bridge in Foshan, China, verified the effectiveness of the proposed evaluation method.

Review of Phased Array Ultrasonic Testing of Weld Joints

Welding is a prevalent joining technique used to metals in welding constructions. It is also very important to detect welding defects that may occur without damaging the constructions. The conventional ultrasonic inspection is the most widely used non-destructive test method for the detection of weld defects. Phased Array Ultrasonic Testing (PAUT) is a significant method within the category of ultrasonic non-destructive testing methods. Because ultrasonic phased arrays offer significant technical advantages over conventional ultrasonic such as improved sensitivity, accurate characterization and faster inspection. The aim of this article is to provide a comprehensive review analysing defects in welded joints by utilizing PAUT. Different literature studies related to the non-destructive testing of weld joints using by PAUT have been reviewed. Various examples of how the type, depth, and size of welding defects are detected in a highly effective manner are provided. As a result, it was concluded that phased array ultrasonic is a highly efficient technique compared to conventional ultrasonic methods for detecting welding defects.

Recent Advancements in Guided Ultrasonic Waves for Structural Health Monitoring of Composite Structures

Structural health monitoring (SHM) is essential for ensuring the safety and longevity of laminated composite structures. Their favorable strength-to-weight ratio renders them ideal for the automotive, marine, and aerospace industries. Among various non-destructive testing (NDT) methods, ultrasonic techniques have emerged as robust tools for detecting and characterizing internal flaws in composites, including delaminations, matrix cracks, and fiber breakages. This review concentrates on recent developments in ultrasonic NDT techniques for the SHM of laminated composite structures, with a special focus on guided wave methods. We delve into the fundamental principles of ultrasonic testing in composites and review cutting-edge techniques such as phased array ultrasonics, laser ultrasonics, and nonlinear ultrasonic methods. The review also discusses emerging trends in data analysis, particularly the integration of machine learning and artificial intelligence for enhanced defect detection and characterization through guided waves. This review outlines the current and anticipated trends in ultrasonic NDT for SHM in composites, aiming to aid researchers and practitioners in developing more effective monitoring strategies for laminated composite structures.

Quantum machine learning for recognition of defects in ultrasonic imaging

The paper discusses a new paradigm of employing a quantum machine learning(QML) algorithm for automated weld defect recognition. A variational quantum classifier (VQC) using ultrasonic phased arrays is proposed to extract weld defect features in the atomic state to improve the classification accuracy and achieve high-speed calculation due to simultaneous qubits. The VQC is trained using a simulation-assisted weld dataset generated using finite element(FE) models and deep convolution generative adversarial networks (DCGAN). The total focusing method (TFM) weld images of porosity and slag are generated using time-transmitted signals received by performing full matrix capture, modeling various defect morphologies using FE simulations. These datasets are fed to train the DCGAN to generate synthetic TFM images. We use the feature selection method to obtain the best results with a quantum circuit with minimal qubits. Prominent features so obtained are supplied to the encoder circuit of the VQC to convert it to a quantum domain, thereby passing to an ansatz circuit to train quantum hyperparameters. The loss is computed for every iteration by optimizing the learnable parameters of the VQC. The VQC is trained by varying quantities of datasets to improve the reliability and efficiency of the weld defect classifications. It is found that VQC outperforms some of the classical machine learning algorithms with an accuracy of 96%.

Development of ultrasonic phased array technique for inspection of fir-tree type turbine blade root and disc-rim in nuclear power plant

ABSTRACT Steam turbines are crucial in both nuclear and thermal power plants, serving a key role in electricity generation. However, the operational lifespan of these turbines is often limited by failures in the turbine blade roots and disc rims due to fatigue, stress corrosion cracking and creep. Usage of reliable non-destructive technique during in-service inspection of turbine assembly is very important for decision making and safe operation of power plant. The conventional ultrasonic technique which is being employed currently suffers from access limitation, high inspection time and false calls during defect detection due to complex geometry of blade roots and disc rims. To address these issues, an advanced ultrasonic inspection technique using phased array technology was developed, specifically tailored for fir-tree type blade roots and disc rims. Ultrasonic Simulation studies were performed to determine the optimal parameters for phased array probes, ensuring the effective detection and precise sizing of crack-like defects. This manuscript presents the findings from these simulations, along with experimental results from phased array inspections of turbine blade root and disc rim mockup of turbine assembly in nuclear power plant.

Fast and Smart State Characterization of Large-Format Lithium-Ion Batteries via Phased-Array Ultrasonic Sensing Technology.

Lithium-ion batteries (LIBs) are widely used in electric vehicles and energy storage systems, making accurate state transition monitoring a key research topic. This paper presents a characterization method for large-format LIBs based on phased-array ultrasonic technology (PAUT). A finite element model of a large-format aluminum shell lithium-ion battery is developed on the basis of ultrasonic wave propagation in multilayer porous media. Simulations and comparative analyses of phased array ultrasonic imaging are conducted for various operating conditions and abnormal gas generation. A 40 Ah ternary lithium battery (NCMB) is tested at a 0.5C charge-discharge rate, with the state of charge (SOC) and ultrasonic data extracted. The relationship between ultrasonic signals and phased array images is established through simulation and experimental comparisons. To estimate the SOC, a fully connected neural network (FCNN) model is designed and trained, achieving an error of less than 4%. Additionally, phased array imaging, which is conducted every 5 s during overcharging and overdischarging, reveals that gas bubbles form at 0.9 V and increase significantly at 0.2 V. This research provides a new method for battery state characterization.

Highly Sensitive Phased Array Probes based on Capacitive Micromachined Ultrasonic Transducers

Capacitive Micromachined Ultrasonic Transducers (CMUTs) offer a wide freedom of design for ultrasonic phased arrays. They are characterized, in comparison to piezoelectric transducers, by a higher sensitivity in receiving and a wider bandwidth based on their physical properties. Especially in combination with integrated preamplifiers the high receiving sensitivity compensates or rather overcompensates the lower transmission power of the CMUT in single probe applications with pulse-echo technique. This asymmetric behavior opens new opportunities in the application. In medical diagnostics it allows to meet the maximum permissible ultrasonic radiation force with the best sensitivity. In nondestructive testing the transmission power can be increased by the combination of a piezoelectric probe for transmitting and a CMUT probe for receiving. Especially in double probe techniques, such as pitch-catch or time-of-flight diffraction (TOFD), this is an efficient extension of the conventional approach with two piezoelectric transducers. The CMUT array probes developed by Fraunhofer IPMS with integrated preamplifier and bias voltage converter powered by a standard USB-A connector can be applied as one to one substitute for piezoelectric phased arrays with commercially available ultrasonic devices without adaption or additional electronics. The CMUT arrays are best suited for immersion technique and medical sonography because of their natural matching to water-like materials. They are applicable as well for solid surfaces with a special coating. We present the first results of ultrasonic imaging with our CMUT array probes in comparison with a commercially available piezoelectric phased array probe.

Contactless printing of food micro-particles controlled by ultrasound

Traditional food 3D printing technology, which primarily relies on mechanical control, often faces challenges such as low resolution, stringent material requirements, limited flexibility, and cumbersome equipment. To overcome these limitations, we developed an innovative food 3D printing method utilizing ultrasonic phased arrays and subsequently designed a contactless printing device employing this advanced technology. The device effectively manipulates the phase and amplitude of the ultrasonic phased array to focus the sound field on a specific location. We have successfully demonstrated preliminary control over the suspension of small food particles, including popcorn, chocolate, honey, and marshmallows, using this apparatus. Following this, popcorn particles were selected for detailed practical printing and further analysis. Additionally, we established a software platform, Ultr_printing, based on Ultraino, for intelligent simulation and control of the printing process. Leveraging FPGA and Arduino controllers, this setup facilitates rapid signal transmission from personal computers to sensors, ensuring quick and adaptable movement of suspended particles. Experimental results confirm that the device consistently controls the food particles, irrespective of their motion state. Notably, it achieves a printing precision of 0.16 mm when handling popcorn particles measuring 1.5 mm in diameter. The process, entirely contactless and free from contamination, preserves the original flavor of the food particles. This technology is particularly effective for high-precision printing of micro-scale shapes and offers considerable benefits in assembly and precision manufacturing.

Metallic material microstructure grain size measurements from backscattering signals in ultrasonic array data sets

Ultrasound backscattering signals from material microstructures can be used to evaluate the material microstructure grain size. This typically involves making pulse-echo immersion measurements at multiple locations using a focused ultrasonic transducer in order to obtain an accurate estimate of the root-mean-square amplitude of the back-scattered signal at a specified focal position. However, this restricts some practical applications of using such techniques in, for example, on-line measurements in high-value manufacturing and in-service inspections where multiple immersion measurements are not feasible to use. The main benefit of using ultrasonic phased arrays is that one array probe at one position can focus ultrasound beams at multiple points using different focal laws either physically or in data postprocessing. Potentially this means that accurate grain size measurements can be obtained from a single array measurement. In this paper, the classic backscattering method for conventional transducers is adapted to be used for full matrix capture datasets from an ultrasonic array. Three-dimensional ultrasonic models are developed in the proposed inverse process to measure material microstructure grain size. Experimental validations were performed on two metallic materials: copper (EN1652) and bright mild steel (BS970). A good agreement is shown between the experimentally measured grain sizes from array data and metallography measurements. Compared to the classic pulse-echo immersion back-scattering measurements, the proposed method enables accurate measurement of grain size in a direct contact configuration at fewer locations. This has potential to make on-line grain size measurements possible.

Application Study of Acoustic Reflectivity Based on Phased Array Ultrasonics in Evaluating Lubricating Oil Film Thickness

Bearings play a key role in rolling mills, and the uniformity of their lubricant film directly affects the degree of wear of bearings and the safety of equipment. Due to long-term stress, the lubricant film inside the bearing is not uniformly distributed, resulting in uneven wear between the journal and the shaft tile, which increases the potential safety hazards in production. Traditional disassembly inspection methods are complex and time-consuming. Ultrasonic nondestructive testing technology, which has the advantages of nondestructive and adaptable, has become an effective means of assessing the thickness of the oil film in bearings. In this study, an experimental platform for calibrating the lubricant film thickness in bearings was constructed for the first time, and the acoustic characteristics of different thicknesses of the oil film were measured using ultrasonic detection equipment to verify the accuracy of the simulation process. The experimental results show that after discrete Fourier transform processing, the main features of the frequency channels of the reflected acoustic signals of different thicknesses of the oil film are consistent with the finite element simulation results, and the errors of the oil film thicknesses calculated from the reflection coefficients are within 10% of the set thicknesses, and the measurement ranges cover from 5 μm to 250 μm. Therefore, the above method can realize the accurate measurement of the thicknesses of the oil film in bearings.

Study of Residual Stress Using Phased Array Ultrasonics in Ti-6AL-4V Wire-Arc Additively Manufactured Components

This paper presents a study on residual stress measurement in wire-arc additively manufactured (WAAM) titanium samples using the non-destructive method of phased array ultrasonics. The contour method (CM) was used for the verification of the phased array ultrasonic results. This allowed for a comparison of measurement methods to understand the effects on the distribution of residual stress (RS) within Ti-6Al-4V samples and the effectiveness of measurement of residual stress using phased array ultrasonics. From the results of the experiments, the phased array ultrasonic data were found to be in good agreement with the CM results and displayed similar residual stress distributions in the samples. The results of the individual elements of the phased array were also compared and an improvement in accuracy was found. From per-element results, anomalies were found and could be mitigated with the ability to average the results by using phased array ultrasonics. Therefore, based on these results, there is a strong case for the benefits of using phased array ultrasonics as a method of residual stress measurement for WAAM Ti-6Al-4V components over other existing residual stress measurement techniques.

Ultrasonic phased array testing to quantify material texture for metal additive manufacturing

Metal additive manufacturing (AM) processes result in complex microstructures, porosity, material texture, and residual stresses. These properties may vary throughout AM parts. Ultrasonic nondestructive evaluation (NDE) is essential for understanding the processes leading to these variations. However, the use of single-element transducers to scan AM parts with complex geometries can be challenging. Such measurements may require multiple scans to level a surface or excite various wave types within a part. On the contrary, phased array ultrasonic transducers (PAUTs) can be much more efficient for these studies. In this presentation, custom AM sample designs are discussed which allow multiple ultrasonic wave speeds to be measured using a PAUT. The manufactured samples were assessed with the sectorial scan feature of the PAUT to scan multiple positions and directions quickly without moving the probe. Data from these scans were then used to estimate material wave speeds, material texture, and residual stress along multiple directions within the samples. The results from these scans were also compared with experiments that used single-element ultrasonic transducers. This presentation will describe the sample designs, the experiments, and the analysis in order to highlight the usefulness of PAUTs for scanning AM parts.

A tunable spatial coherence imaging with ultrasonic array for defects in composites

ABSTRACT Ultrasonic phased array detection technology is a promising non-destructive testing (NDT) method that has been widely used for defect detection. Due to the high attenuation characteristics of ultrasonic wave propagation in carbon fibre reinforced polymer (CFRP) and the directivity of the array elements, the possibility of false or missed detection for defects that are far from the array elements or located very close together will increase. In addition, the total focusing method (TFM) employs only the defect information contained in the full matrix capture (FMC) dataset while ignoring the spatial information of the array signals, leading to image mixed with artefact and noise. An improved method called p-weighted-TFM (p-WTFM) is proposed. First, this method scales the magnitude of time-delayed channel signal by p-th root while maintaining the phase unchanged. Second, channel summation with energy compensation and directional correction will be realised. Finally, the signal dimensionality is restored by p-th power. Experimental results show that the p-WTFM can use any rational p-value to flexibly adjust image quality. Specially, this method can accurately distinguish adjacent defects spaced 1 mm apart with p value of 2.5, and it can also detect two defects located 10 mm deep with p value of 3.0.

Round robin experiment to detect, size, and characterize flaws in the welds of existing hydraulic steel structures using phased array ultrasonic testing

Limited information exists on the ability of nondestructive testing techniques to detect, size, and characterize flaws in existing hydraulic steel structures (HSS). Round robin experiments were conducted using phased array ultrasonics to inspect welded steel specimens representing joints in existing HSS. Technicians detected 83% of the flaws scanned, but detection rates varied widely by flaw and technician. Uncertainty in flaw size estimates, represented by 90% confidence bounds on the ratio of estimated to actual length or height, ranged from 0.52 to 2.10 for length and 0.32 to 3.59 for height. Planar, volumetric and laminar flaws were accurately characterized 80% of the time.

Research on defect identification of carbon fiber composite materials based on ultrasonic phased array

AbstractIt is more and more difficult to identify defects in carbon fiber composite materials due to the difficulty in making defect samples and the single signal analysis method. In order to better solve the problem of defect identification in carbon fiber composite materials, this study uses ultrasonic phased array equipment to quantitatively locate and detect carbon fiber composite laminates with embedded delamination defects, so as to more intuitively and effectively display the appearance of different delamination defects. The time domain analysis of the collected ultrasonic original signal and the time‐frequency domain analysis using wavelet packet are carried out. A total of 6 eigenvalues were extracted to reflect the ultrasonic signals of different delamination defects. By using genetic algorithm to optimize BP neural network, the recognition accuracy of delamination defects of different sizes is more than 95%, and the recognition accuracy of delamination defects of different depths is 100%, so as to realize the effective intelligent recognition of delamination defects of different sizes and depths of carbon fiber composites. This study is of great significance to improve the accuracy and reliability of defect identification of carbon fiber composite materials.Highlights The ultrasonic phased array equipment is used to quantitatively locate the carbon fiber composite laminates with embedded delamination defects, so that the appearance of different defects can be displayed more intuitively and effectively. Using time domain analysis and time‐frequency domain analysis based on wavelet packet, the combination of the two can more comprehensively extract the effective features of the defect signal. The BP neural network is optimized by genetic algorithm, and the results can effectively and automatically identify different layered defects, which lays a good foundation for the rapid and accurate identification of more defects in the future.

Nonlinear ultrasonic Lamb wave phased array imaging based on hybrid array and time-reversal of harmonic

Fatigue cracks, as one of the early performance deteriorations of plate-like structures, are critical to be detected in a timely manner to prevent further failures and disastrous accidents. But the intimate contact of crack interfaces is difficult to form a significant scattering field of traditional ultrasonic Lamb waves, resulting in the insensitivity of Lamb wave phased array-based imaging methods to crack imaging. To break through the detecting limitations of conventional Lamb wave phased array, the nonlinear Lamb wave-based phased array method is first proposed to realize fatigue crack imaging, which is achieved by a new form of phased array with hybrid elements, signal processing for harmonic enhancement and time-reversal based harmonic field focusing. The hybrid array is designed for efficient transmission and capture of fundamental wave and harmonics, and Pulse-inversion technology and continuous wavelet transform filter are used to extract and enhance second harmonic response, and the images are obtained by the time domain topological energy imaging algorithm. Finally, the imaging results of barely visible fatigue cracks and through-holes in metallic plate structures using linear and nonlinear Lamb wave-phased array are compared. The nonlinear ultrasonic Lamb wave-phased array demonstrates excellent capability of fatigue crack imaging.

Adaptive total focusing method for ultrasonic full-matrix imaging of anisotropic CFRP laminates

Abstract The application of total focusing method (TFM) for imaging of Carbon fiber reinforced plastics (CFRP) with ultrasonic phased array is particularly challenging due to the layered structure and anisotropy of CFRP. To improve the TFM imaging performance, the precise knowledge of complex ultrasonic paths in anisotropic CFRP laminates should be obtained for accurate calculation of time of flights (TOFs), which makes the inspection process complicated and time-consuming. In this work, an adaptive TFM is developed for full-matrix imaging of CFRP laminates using ultrasonic phased array. Based on the acquired full matrix data, the elastic constants, including C 11, C 22, C 55, and C 13, can be directly derived using TOFs of A-scan signals. Based on the measured elastic constants, group velocity profiles of quasi-pressure (QP) wave were then calculated for different stacking sequences, from which the TOFs were corrected. To verify the effectiveness of proposed method, simulations and experiments are demonstrated on the CFRP laminates with different stacking sequences. As a representative example, the delamination defects are showcased. Compared with isotropic TFM, the SNR of proposed method is increased by 10.2-18.0 dB. The simulated and experimental results agreed well with each other, indicating that the feasibility of proposed method in full matrix imaging of anisotropic CFRPs.

Phased Array Ultrasonic Inspection of Composite Fuselage Panel

Abstract The composite fuselage panel is a crucial component in large civil aircraft, necessitating higher detection rates and efficiency. Phased array ultrasonic testing can enhance the efficiency and defect detection rate; however, it is essential to consider the structural characteristics of the fuselage to ensure reliable identification of design defects. Based on the material properties, structural features, and defect detection requirements of composite fuselage panels, a test block reflecting their characteristics was designed and fabricated with various prefabricated defects. Ultrasonic phased array method was employed for a series of testing parameter optimization experiments and defect detectability analysis. The detected flaws were quantitatively analyzed and compared with those obtained using conventional ultrasonic automatic scanning techniques to validate the effectiveness of the developed ultrasonic phased array method. The feasibility of utilizing phased array ultrasonics for nondestructive evaluation of wide-body airliner composite fuselage panels is confirmed.