Showing papers on "Guided wave testing published in 2021"

Review of Current Guided Wave Ultrasonic Testing (GWUT) Limitations and Future Directions.

Abstract: Damage is an inevitable occurrence in metallic structures and when unchecked could result in a catastrophic breakdown of structural assets. Non-destructive evaluation (NDE) is adopted in industries for assessment and health inspection of structural assets. Prominent among the NDE techniques is guided wave ultrasonic testing (GWUT). This method is cost-effective and possesses an enormous capability for long-range inspection of corroded structures, detection of sundries of crack and other metallic damage structures at low frequency and energy attenuation. However, the parametric features of the GWUT are affected by structural and environmental operating conditions and result in masking damage signal. Most studies focused on identifying individual damage under varying conditions while combined damage phenomena can coexist in structure and hasten its deterioration. Hence, it is an impending task to study the effect of combined damage on a structure under varying conditions and correlate it with GWUT parametric features. In this respect, this work reviewed the literature on UGWs, damage inspection, severity, temperature influence on the guided wave and parametric characteristics of the inspecting wave. The review is limited to the piezoelectric transduction unit. It was keenly observed that no significant work had been done to correlate the parametric feature of GWUT with combined damage effect under varying conditions. It is therefore proposed to investigate this impending task.

Damage Identification of Pipeline Based on Ultrasonic Guided Wave and Wavelet Denoising

Abstract: Guided wave technology shows excellent capacity in the damage identification of the pipeline. In practical inspection, the detection ability is greatly reduced due to the interference echo ...

Rapid detection of cracks in the rail foot by ultrasonic B-scan imaging using a shear horizontal guided wave electromagnetic acoustic transducer

Abstract: Transverse cracks in the rail foot are responsible for the breaking of the rail. The existing non-destructive testing technology for high-speed railway track is difficult to perform in-situ and rapid detection for the rail foot, which poses a hidden danger to driving safety. In this study, a new method is proposed for the in-situ and rapid detection of cracks in the rail foot by ultrasonic B-scan imaging. A finite element method (FEM) based on the Bloch–Floquet boundary and domain constraint were employed to calculate the dispersion curves of shear horizontal (SH)-like guided waves propagating in the rail foot. SH guided waves mainly vibrate with in-plane displacement, and they are less affected by the rail components such as elastic clips and pads. Based on the calculated dispersion curves, an SH-guided wave electromagnetic acoustic transducer (EMAT) with a center frequency of 0.154 MHz was developed, and ultrasonic B-scan imaging was performed to detect straight cracks in the rail foot. Besides, the synchrosqueezed wavelet transform (SWT) method was proposed to remove noises and higher-order guided wave modes from the original ultrasonically detected signals. Results show that FEM with the Bloch–Floquet boundary and domain constraint can be used to solve the dispersion curves of the SH-like guided waves of the rail foot accurately and easily. The application of SWT can increase the lift-off of the EMAT, eliminate the noise, remove the higher-order SH-like guided wave modes, improve the detection efficiency, and enhance the quality of ultrasonic B-scan images. After the SWT processing, the signal-to-noise ratio (SNR) of the ultrasonic signal is increased by at least 5.98 dB. When the lift-off of the EMAT is 4 mm and without synchronous averaging, the on-line and rapid ultrasonic B-scan imaging of the rail foot using guided wave EMAT can still achieve a reasonable SNR.

Guided wave propagation of porous functionally graded plates: The effect of thermal loadings

Abstract: Because there is no literature on the effect of thermal loadings on guided wave propagation in FG plates, the present paper is to fill the gap. In the present paper, the wave propagation analysis o...

Sparse Bayesian learning approach for propagation distance recognition and damage localization in plate-like structures using guided waves:

Abstract: In ultrasonic guided wave–based damage detection, the propagation distance recognition of wave packets is an essential step. However, it is difficult to perform direct distance extraction from guid...

Distribution adaptation deep transfer learning method for cross-structure health monitoring using guided waves:

Abstract: Deep learning algorithm can effectively obtain damage information using labeled samples, and has become a promising feature extraction tool for ultrasonic guided wave detection. But it is difficult...

Defect sizing in guided wave imaging structural health monitoring using convolutional neural networks

Abstract: This paper proposes an automatic defect localization and sizing procedure for Structural Health Monitoring based on guided waves imaging. The procedure is applied to an aluminum plate equipped with active piezoelectric sensors. The defect localization and sizing strategy is obtained through to the use of a convolutional neural network trained exclusively on numerical simulations of guided wave signals and post-processed by the delay and sum imaging algorithm. The paper shows the effectiveness of the proposed approach to invert both synthetic and experimental data.

Non-reciprocal Rayleigh wave propagation in space-time modulated surface

Abstract: Research on non-reciprocal propagation of waves is of great significance in the field of photonic and phononic crystals for realizing flexible one-way propagation devices with potential engineering applications. Here, non-reciprocal Rayleigh waves are investigated in a continuous two-dimensional (2D) semi-infinite medium bound with an array of space–time modulated spring–mass oscillators. The involved modulation is a wave-like perturbation of the surface of the continuous medium that breaks time-reversal symmetry and reciprocity. To characterize the propagation of Rayleigh waves in such a complex 2D medium with continuous and discrete interface, an analytical study is performed to obtain dispersion-engineered bandgaps by adopting the asymptotic method and coupled mode theory, which is also validated by numerical simulation. Specifically, the non-reciprocal transmission of Rayleigh waves with one-way mode conversion is illustrated, and various relevant physical quantities, including conversion length and band gap size, are quantitatively estimated. This work sheds light on versatile control of Rayleigh wave propagation ranging from sensing and evaluation of engineering structures to guided wave-based damage detection techniques.

Deep Convolutional Neural Network Probability Imaging for Plate Structural Health Monitoring Using Guided Waves

Abstract: Guided wave imaging can obtain the damage characterization of imaging features and time difference, and has become a promising tool for structural health monitoring. But most current imaging algorithms still manually select imaging features from first wave or scatter signal. Such manual feature extraction method highly depends on the selection criterion and would significantly reduce the generalization of the monitoring model. In this article, a deep convolutional neural network probability imaging algorithm (DCNN-PIA) is proposed to provide an automatic high-level damage index extraction method for guided wave imaging. Feature selection and multisensor imbalance can be turned away in this semisupervised deep learning method, and the damage will be presented visually. The experiment results illustrate that the proposed method can detect the damage only by using normal state signals, presents a good materials generalization in both aluminum plate and composite plate, and has better performance than other state-of-the-art methods.

SSWT and VMD Linked Mode Identification and Time-of-Flight Extraction of Denoised SH Guided Waves

Abstract: Ultrasonic guided wave testing technology is currently widely used in industrial nondestructive testing (NDT), including defect detection in the floors of large tanks and oil pipelines. However, in addition to noise, practical scenarios of signal detection also present mode aliasing problems, which make it difficult to accurately identify and locate defects. In this paper, we propose an improved shear horizontal guided wave mode identification method using a variational mode decomposition (VMD) algorithm and a time-of-flight (TOF) extraction method using the synchrosqueezed wavelet transform (SSWT) algorithm. Moreover, we use the wavelet denoising method to denoise the original signal before applying VMD. The results show that the TOF errors obtained by the VMD method are all less than 5% and that the wavelet denoising of the original guided wave data can further reduce the errors (to less than 2%). In addition, the SSWT can modify the time-frequency analysis results of intrinsic mode functions obtained by the VMD method and provides accurate TOF data for different modes. Therefore, the proposed ultrasonic guided wave signal method is helpful for improving the defect detection sensitivity and accuracy of SH waves.

Development of Frequency-Mixed Point-Focusing Shear Horizontal Guided-Wave EMAT for Defect Inspection Using Deep Neural Network

Abstract: We propose a new frequency-mixed point-focusing shear horizontal (SH) guided-wave electromagnetic acoustic transducer (EMAT) in this work to obtain the defect positions and plate thickness simultaneously and accurately. Compared with other guided-wave detection methods, it is not required to measure the plate thickness in advance because we can easily obtain it during the test. We use the variational mode decomposition method to decompose the received frequency-mixed defect signal into subsignals with different center frequencies and to remove the noise. Furthermore, we use the continuous wavelet transform to analyze these subsignals using the time–frequency method and to obtain the time-of-flight information of the guided wave under different frequencies and modes. Therefore, we can obtain accurate defect positions and plate thicknesses via the new transducer and signal processing methods while improving the signal intensities. In the identification of defect types, we first constructed a database set containing three types of defects of different sizes using data enhancement methods. Then, the dense network, convolutional neural network, recurrent neural network, and newly proposed deep GFresNet are studied to analyze the defect classification performance of each structure. The results show that the proposed GFresNet has very good defect identification accuracy, which is about 95% along any depth of the defects, and that it can automatically extract high-level information without sophisticated feature engineering.

Noncontact super-resolution guided wave array imaging of subwavelength defects using a multiscale deep learning approach:

Abstract: Subwavelength defect imaging using guided waves has been known to be a difficult task mainly due to the diffraction limit and dispersion of guided waves. In this article, we present a noncontact su...

Damage Quantification in an Aluminium-CFRP Composite Structure using Guided Wave Wavenumber Mapping: Comparison of Instantaneous and Local Wavenumber Analyses

Abstract: Composite-overwrapped pressure vessels (COPV) are increasingly used in the transportation industry due to their high strength to mass ratio. Throughout the years, various designs were developed and found their applications. Currently, there are five designs, which can be subdivided into two main categories - with a load-sharing metal liner and with a non-load-sharing plastic liner. The main damage mechanism defining the lifetime of the first type is fatigue of the metal liner, whereas for the second type it is fatigue of the composite overwrap. Nevertheless, one damage type which may drastically reduce the lifetime of COPV is impact-induced damage. Therefore, this barely visible damage needs to be assessed in a non-destructive way to decide whether the pressure vessel can be further used or has to be put out of service. One of the possible methods is based on ultrasonic waves. In this contribution, both conventional ultrasonic testing (UT) by high-frequency bulk waves and wavenumber mapping by low frequency guided waves are used to evaluate impact damage. Wavenumber mapping techniques are first benchmarked on a simulated aluminium panel then applied to experimental measurements acquired on a delaminated aluminium-CFRP composite plate which corresponds to a structure of COPV with a load-sharing metal liner. The analysis of experimental data obtained from measurements of guided waves propagating in an aluminium-CFRP composite plate with impact-induced damage is performed. All approaches show similar performance in terms of quantification of damage size and depths while being applied to numerical data. The approaches used on the experimental data deliver an accurate estimate of the in-plane size of the large delamination at the aluminium-CFRP interface but only a rough estimate of its depth. Moreover, none of the wavenumber mapping techniques used in the study can quantify every delamination between CFRP plies caused by the impact, which is the case for conventional UT. This may be solved by using higher frequencies (shorter wavelengths) or more advanced signal processing techniques. All in all, it can be concluded that imaging of complex impact damage in fibre-reinforced composites based on wavenumber mapping is not straightforward and stays a challenging task.

Guided wave–based rail flaw detection technologies: state-of-the-art review:

Abstract: The unavoidable increase in train speed and load, as well as the aging of railway facilities, is requiring more and more attention to rail defects detection. As a promising tool for rail, in-servic...

Forward stimulated Brillouin scattering and opto-mechanical non-reciprocity in standard polarization maintaining fibres.

Abstract: Opto-mechanical interactions in guided wave media are drawing great interest in fundamental research and applications. Forward stimulated Brillouin scattering, in particular, is widely investigated in optical fibres and photonic integrated circuits. In this work, we report a comprehensive study of forward stimulated Brillouin scattering over standard, panda-type polarization maintaining fibres. We distinguish between intra-polarization scattering, in which two pump tones are co-polarized along one principal axis, and inter-polarization processes driven by orthogonally polarized pump waves. Both processes are quantified in analysis, calculations and experiment. Inter-modal scattering, in particular, introduces cross-polarization switching of probe waves that is non-reciprocal. Switching takes place in multiple wavelength windows. The results provide a first demonstration of opto-mechanical non-reciprocity of forward scatter in standard fibre. The inter-polarization process is applicable to distributed sensors of media outside the cladding and coating boundaries, where light cannot reach. The process may be scaled towards forward Brillouin lasers, optical isolators and circulators and narrowband microwave-photonic filters over longer sections of off-the-shelf polarization maintaining fibres.

Defect Detection in Pipelines via Guided Wave-Based Time–Frequency-Domain Reflectometry

Abstract: In order to improve the performance of the conventional guided wave testing (GWT) with a low sensitivity on damage in pipelines, a new GWT based on time–frequency-domain reflectometry (TFDR) is proposed TFDR using electromagnetic signals is a diagnostic technique for electrical cables, and the signal is analyzed in both time and frequency domains to enhance the resolution of faults in the electrical cables Since it is impossible to directly apply the TFDR methodology for electrical cables to the pipelines, this article presents new TFDR methodologies suitable for the ultrasonic characteristics of the pipelines The proposed technique is demonstrated by experiments using a real-world pipeline The analysis of the experimental results depending on the changes in the defect size and internal material of the pipeline is provided, and the performance of the proposed technique is confirmed by the experiments

Excitation of Single-Mode Shear-Horizontal Guided Waves and Evaluation of Their Sensitivity to Very Shallow Crack-Like Defects

Abstract: Inspection is a key part of the asset management process of industrial plants and there are numerous plate-like structures that require inspection. Ultrasonic guided waves have been extensively used to detect various types of defect by monitoring reflected and transmitted signals because they enable faster screening of large areas. However, ultrasonic guided wave testing becomes difficult for very shallow, sharp defects as current inspection techniques suffer from a lack of sensitivity to such features. Previous studies, obtained by comparing various inspection techniques, suggest that the SH1 mode in particular, at around 3 MHz $\cdot$ mm, would be suitable when testing for shallow defects; however, it is clear that both the SH0 and SH1 modes can exist at this frequency–thickness product. This can complicate the inspection process and, therefore, limit defect detectability. This article investigates the possibility of a single-mode excitation of the SH1 mode at around 3 MHz $\cdot$ mm. The ability of this method toward detecting very shallow defects (<10% cross-sectional thickness loss) has also been studied. By means of analytical predictions and finite element, it is shown that a signal dominated by the SH1 mode can be generated using a single permanent periodic magnet (PPM) electromagnetic acoustic transducer (EMAT) (PPM EMAT). All predictions are then backed up by experimental measurements. It is also shown that, by studying the reflection coefficient of the SH1 mode, the pure SH1 mode can be used to detect defects as shallow as 5% thickness loss from a 500-mm stand-off. These defects would otherwise be missed by standard, lower frequency guided wave testing.

Debonding detection in rebar-reinforced concrete structures using second harmonic generation of longitudinal guided wave

Abstract: Nonlinear features of ultrasonic guided waves (GWs) is studied for debonding detection and location estimation in rebar reinforced concrete structure. The study shows that the presence of debonding between steel rebar and concrete surface produces breathing phenomenon causing contact acoustic nonlinearity (CAN), which generates second harmonics. Time-frequency analysis is used to estimate the location of debonding in this study. At a particular frequency, embedded rebar has much greater number of wave modes in bare rebar. To avoid unnecessary complexity, only longitudinal GW modes for bare and embedded rebar are excited and received to detect and locate debonding. To precisely determine the wave mode at excited frequency and frequency of second harmonics, frequency-wavenumber analysis is performed using 2D-Fast Fourier Transform of time-space data. Three-dimensional explicit finite element simulations are performed for various case studies and the model is validated by experimentally measured data. The results of this study show that the proposed method is practically viable and beneficial for debonding detection and location estimation in reinforced concrete structures.

Axial guided wave characteristics in functionally graded one-dimensional hexagonal piezoelectric quasi-crystal cylinders:

Abstract: In one-dimensional hexagonal piezoelectric quasi-crystals, there exist the phonon–phason, electro–phonon, and electro–phason couplings. Therefore, the phonon–phason coupling and piezoelectric effec...

State-of-charge and state-of-health estimation for lithium-ion battery using the direct wave signals of guided wave

Abstract: With the development of new energy technology, lithium-ion battery, as a common energy storage and driving structure, has been widely used in many fields. It is significant to accurately monitor and evaluate the state of charge (SOC) and state of health (SOH) of lithium-ion battery. This paper presents the estimation method of SOC and SOH of lithium-ion battery based on ultrasonic guided wave technology. In the experiment, the guided wave signals are activated by a single fixed piezoelectric transducer and the propagating guided waves are rapidly captured using a scanning laser Doppler vibrometer system. The multi-parameter analysis of the direct wave signals including time-domain, frequency-domain and time-frequency distribution are performed, and thus three guided-wave parameters, namely signal amplitude, time of flight and power spectral density connected with the charge discharge cycle and aging of battery, are successively set to comprehensively evaluate SOC/SOH of lithium-ion battery. The results show that the guided wave parameters in time-domain, frequency-domain and time-frequency distribution have well consistent correspondence with SOC/SOH, and the differential curve analysis of signal amplitude can effectively reflect the phase transitions in the charge-discharge cycle and the aging process. In addition, the sensitivity of ultrasonic guided wave technology to estimation of SOC/SOH gradually decreases with the battery aging.

Seismic inversion of shale reservoir properties using microseismic-induced guided waves recorded by distributed acoustic sensingDAS microseismic guided wave inversion

Abstract: Shale formation properties are crucial for the hydrocarbon production performance of unconventional reservoirs Microseismic-induced guided waves, which propagate within the low-velocity sh