Nondestructive Testing Applications Research Articles

Inorganic metal oxide material BaSiO3:Eu2+ for convenient 3D X-ray imaging

X-ray storage phosphors are found wide-ranging applications in medical diagnosis, nondestructive testing and X-ray imaging. However, designing X-ray storage phosphors with high electron storage capacity still poses a daunting challenge. In this study, we designed a fluorescent powder based on Eu2+-doped BaSiO3, demonstrating excellent optical information storage characteristic. Under high-energy X-ray filling, shallow traps exhibit low electron capacity and only produce weak afterglow, which greatly helps to minimize the impact of afterglow on the image quality during X-ray imaging. In addition, the deep traps at 1.01 eV filled with high-energy X-ray allow the material to store information for a long time. The crystal structure, photoluminescence (PL) and thermoluminescence (TL) spectra were studied systematically. The electron trapping properties of the material were analyzed using TL spectroscopy. Finally, we fabricated a flexible film with phosphors, the flexible film has been utilized to demonstrate high-quality real-time X-ray imaging and achieve time-delayed X-ray imaging of curved objects, such as flexible circuit boards.

Five-Band Tunable Terahertz Metamaterial Absorber Using Two Sets of Different-Sized Graphene-Based Copper-Coin-like Resonators

In this paper, a five-band metamaterial absorber with a tunable function in a terahertz band is proposed, which consists of a gold grounding layer, a polyimide dielectric layer, and a periodic patterned graphene layer. The patterned graphene layer is constructed from two sets of copper-coin-shaped structures of different sizes. The designed absorber achieves absorptions of 96.4%, 99.4%, 99.8%, 98.4%, and 99.9% at 4.62 THz, 7.29 THz, 7.70 THz, 8.19 THz, and 8.93 THz, respectively, with an average absorption intensity of 98.78%. The physical mechanism of this five-band absorber was explained by the impedance matching principle and electric field distribution. The absorption performance of the five-band absorber can be effectively tuned by changing the geometry of the patterned graphene array and the thickness of the dielectric layer. Given that the resonant frequency of the absorber varies in proportion to the Fermi level, by varying the Fermi level of the graphene hypersurface, we can achieve the continuous tuning of the absorption performance over a wide frequency range. The five-band absorber has a stable absorption performance over a wide incidence angle of 0–65°, and by combining the merits of high absorption, dynamic adjustability, and a large number of absorption peaks, the given absorber could have great potential for applications in nondestructive testing, imaging, communication, sensing, and detectors.

Acoustic shadow zone of the guided wave in a variable thickness plate

This paper calculates the acoustic shadow zone of the guided wave in a variable thickness plate. The variable thickness plate has a wide range of applications in bridges, ships, etc., and the guided wave is often used for its nondestructive testing. The velocity gradient induced by thickness variations will deflect the guided wave towards lower phase velocities. Both frequency and thickness variation play crucial roles in determining the extent of path bending. In particular, the guided wave can undergo reverse propagation at the non-boundary of the plate. This curved propagation path results in an acoustic shadow zone, inaccessible to direct waves. This article calculates and experimentally verifies the curved propagation path of dispersive guided waves. Experiments show that the degree of propagation path bending increases with the increase of frequency in a certain frequency range. On the path that varies along the thickness, the experiment observes an acoustic shadow zone that accounts for nearly 25% of the total path. Additionally, a practical case study involving a guided wave with a curved path is presented. Consideration of the curved path improves the positioning accuracy, offering insights into damage location in variable thickness plates. This research on the propagation path and acoustic shadow zone contributes to advancing the understanding of guided wave propagation characteristics and enhancing their application in nondestructive testing for variable thickness structures.

Controlled Creating of Delaminations in Concrete for Nondestructive Testing

Locating and sizing delaminations is a common inspection task in the maintenance and quality control of construction and rehabilitation. Their detection is an important area of application of nondestructive testing in civil engineering (NDT-CE). To improve this application, NDT test systems and test solutions must be compared, for which specimens containing well-defined delaminations are needed to serve as a reference. Currently, there are no widely accepted procedures available for creating such flaws locally and reproducibly. This study presents procedures for creating artificial delaminations repeatably and as close as possible to natural delaminations. To produce the discontinuities only substances were used which can occur in concrete components and do not affect the application of NDT-CE methods. Ultrasonic pulse-echo (UPE) was used to test the flaws in the specimens. The delaminations were created by applying expansive mortar in prepared through holes. Three specimens with two delaminations each were built and tested using UPE.

The electromechanical coupling property and vibration behavior in 1-3 type piezoelectric composites

Electromechanical coupling coefficient (kt) of piezoelectric composite is the core indicator for medical ultrasonic, nondestructive testing and underwater acoustic transducers applications. Generally, the kt of piezoelectric composite is susceptible to be interfered by its structure parameter and spurious modes. In this work, we figured out the effect of the polymer on the vibration mode by fixing the size of the piezoelectric rod and changing the content of different softness polymer. The spurious modes were related with resonant standing wave caused by classical Bragg scattering in periodic structures. The propagation of spurious mode vibration can be cut off by soft polymer. The maximum kt of 69% was obtained at a Pb(Zr,Ti)O3 (PZT4) ceramic volume fraction of 24.5%. The kt was 5% ∼ 10% higher than that of other reported PZT4 ceramic composites and comparable to PZT5 ceramic composites. This work presented a paradigm for vibration modes modulation by changing the polymers ratio, which providing ideas for excellent performance acoustic transducer designing.

Application of ultrasonic non-destructive testing in industrial pipeline inspection

Abstract This study focuses on applying ultrasonic non-destructive testing (UT) technology in industrial pipeline inspection, exploring the physical basis of ultrasound and its effectiveness in pipeline defect detection to improve industrial pipeline safety and reliability. We present the basic physical principles of ultrasound, including its propagation properties and reflection mechanisms. The research methodology includes the analysis of the reflection and refraction characteristics of the ultrasonic technology on different curved surfaces of the pipeline, as well as the establishment of probabilistic models to analyze the inspection data. The results show that the ultrasonic detection technology has a high degree of accuracy in detecting pipeline defects. For example, after 40 repeated inspections, the measurement errors of defect length and depth were less than 10%, of which the length measurement error of defect 2 was 7.14% and the depth error was 7.54%. The conclusion shows that ultrasonic non-destructive testing technology can be effectively applied to the safety inspection of industrial pipelines with high reliability and accuracy, which is of great significance for ensuring industrial safety.

Feasibility of application of Non-Destructive Testing (NDT) methods to detect hidden damage in masonry structures

Feasibility of application of Non-Destructive Testing (NDT) methods to detect hidden damage in masonry structures

RECONSTRUCTION OF BURIED THERMAL SOURCES FROM SURFACE TEMPERATURE FIELDS BY BAYESIAN INFERENCE

Early detection of defects (e.g., cracks, delamination in composites, defects in adhesive bonds) is critical to prevent potential accidents in industrial environments. Traditional nondestructive testing (NDT) methods, such as thermal techniques, can be used to detect and characterize defects buried in the material. In several of these methods, the material is mechanically excited in such a way that the defects behave like heat sources. By studying the resulting thermal fields, inverse methods have been developed to reconstruct these heat sources and, therefore, even more so defects. The reconstruction of volumetric heat sources buried in material is notably ill-posed and requires the use of specific tools, which makes it difficult to reconstruct both the position and, in particular, the source intensity value. In this paper, an algorithm based on a Bayesian approach is proposed. A prior modeling in the form of a mixture of distributions is considered, which promotes spatial sparsity and thereby regularizes the inference problem. This method enables the reconstruction of sources with high fidelity, including the estimation of intensities. Its performance is discussed in relation to noise, and it is compared to other methods, showing favorable potential for NDT applications.

Research on Electromagnetic Sensing Detection Technology for Non-Destructive Testing Applications

Abstract Nondestructive testing technology, as an indispensable part of modern industrial production, is of great significance for guaranteeing product quality, improving production efficiency, and ensuring production safety. This paper is based on nondestructive testing and electromagnetic sensing detection technology research. The study first adopts ACFM detection to analyze the sensitivity of the surface defect parameters of the material to be detected, and based on the analysis of the magnetic circuit of the electromagnetic sensing structure, to build a mathematical model of ACFM and electromagnetic coupling probe, and then through the magnetic method of non-destructive testing on the material cracks in the detection of the signal effect of the study. The results show that the amplitude of the response signal increases with the increase of the defect angle from 0 to 7 ms, reaching a maximum value of 0.24–0.26 around 6 ms. The amplitude of the response signal decreases with the decrease of the defect angle from 7 to 14 ms and reaches a minimum value of −0.16–0.18 around 14.5 ms. The amplitude of the detection signal is related to the depth of the crack and the length of the surface defect of the steel sheet specimen. The crack depth and surface defect length of the steel plate specimen influence the detection signal’s magnitude. When the defect depth and surface length of the steel plate specimen are 1.5 mm, the detection signal value is weak, and the noise on the surface of the steel plate specimen has a significant effect on the detection signal. Promoting the development and application of NDT technology is greatly aided by the results of this paper.

An efficient and thermally stable source with Cr3+ near-infrared luminescence for non-destructive testing applications

The quest for efficient and heat-resistant near-infrared (NIR) phosphors to create advanced smart NIR lighting sources continues to pose a significant challenge. This study introduces a new fluoride phosphor, Cr3+-doped Cs2NaScF6, wherein the Cs2NaScF6 host provides a weak crystal field suitable for Cr3+ doping. This arrangement allows the production of a broad NIR emission peaking at 797 nm, coupled with a notable internal quantum efficiency of 90.8 % when excited by 446 nm blue light. Meanwhile, due to the relatively mild electron-phonon coupling effect and a high activation energy within this phosphor, the overall NIR emission intensity at 150 °C sustains 81.8 % of its level at room temperature. This highlights exceptional thermal stability in photoluminescence performance. Combining the Cs2NaScF6:Cr3+ phosphor with a commercially available blue InGaN chip to construct a NIR light-emitting diode (LED) device, which exhibits efficient and stable NIR emission, making it suitable for non-destructive testing applications. These findings affirm that the Cs2NaScF6:Cr3+ phosphor can function as a promising candidate to fabricate high-performance device for NIR spectroscopy application.

Nondestructive testing of internal defects by ring-laser-excited ultrasonic

ABSTRACT To improve the excitation efficiency, detection utilisation rate, and signal-to-noise ratio of the laser ultrasonic non-destructive testing of internal defects, the spatial distribution of the excitation light source was changed to a ring-shaped laser source to excite ultrasound. Finite element analysis method was used to simulate and analyse the ultrasonic characteristics excited by the ring laser. The superposition of shear waves on the central axis of a ring laser exhibits considerable advantages for internal defect detection. Consequently, a method was proposed for detecting internal defects using a ring laser to excite and receive ultrasonic waves at the concentric and opposite positions of the ring laser. A ring-source laser ultrasonic detection system was designed to scan and detect circular hole defects with different diameters as well as crack defects with different depths, lengths, and inclination angles. The experimental results showed that the ring-source laser ultrasonic technique could effectively detect defect positions and depths and describe the defect length and external contour under certain conditions. Moreover, it could achieve more complex detection tasks. This study provides an effective reference for the application of laser ultrasonic non-destructive testing of internal defects.

Guided waves in long range nondestructive testing and structural health monitoring: Principles, history of applications and prospects

The early work on long range guided wave nondestructive testing (NDT) was largely done in industry, and multiple applications were developed before a surge in academic interest starting in the early 1990s. This paper reviews the history of the field, covering the topics that must be addressed in the design of a test procedure, as well as applications in both NDT and Structural Health Monitoring (SHM). The use of guided waves in long range NDT is relatively mature, and largely limited to simple structures in applications that are difficult or impossible to address by conventional point inspection methods. Point methods are impractical in most large area SHM applications where it is necessary to detect isolated defects since it is not possible to cover the whole area of interest with transducers. Guided waves therefore have great potential in SHM as they enable a large area of structure to be monitored from a limited number of transduction locations, so reducing the added weight, cost and complexity of the attachment to the structure. It is also possible to improve the sensitivity of the test relative to that obtained in one-off inspection by monitoring the change in signals with time using baseline subtraction. Current SHM deployments are largely in the same types of structure as those where guided wave NDT is used, but there is substantial potential for increasing the range of applications. The paper concludes with a review of the research and development needs for this potential to be realised.

Applicability of available NDT methods for damage detection in concrete elements reinforced or strengthened with FRP

The application of Fiber Reinforced Polymer (FRP) materials in concrete structures has been rising due to their several advantages, including lightweight, high tensile strength, ease of installation, and corrosion resistance. They have been mostly implemented for strengthening and repairing existing structures in the form of an externally bonded system, i.e., sheet, jacket, near surface mounted. Furthermore, they have been recently utilized as internal reinforcement of concrete elements in the form of strands, bars, tendons, etc. Although higher durability and performance are associated with the FRP material in some aspects compared to steel, concerns remain regarding damages and defects in this material, many of which are related to their unique features. Importantly, debonding of FRP materials from a concrete surface or within a concrete element has always been an issue resulting in the premature failure of the structure. To this end, concrete elements strengthened or reinforced with FRP materials has to be inspected periodically to detect potential issues and hence prevent any premature failures. This study first determines all possible or potential damages and anomalies attributed to FRP reinforced/strengthened concrete (FRP-RSC) elements. It then investigates Non-Destructive Testing (NDT) methods that can be applicable to the inspection of FRP-RSC elements from a literature survey of past studies, applications, and research projects. Furthermore, this study evaluates the ability of two of the most commonly used NDT methods, Ground Penetrating Radar (GPR) and Phased Array Ultrasonic (PAU), in detecting FRP bars/strands embedded in concrete elements. GPR and PAU tests were performed on two slab specimens reinforced with GFRP (Glass-FRP) bars, the most commonly used FRP bar, with variations in their depth, size and configuration, and a slab specimen with different types of available FRP reinforcements. The results of this study propose the most applicable methods for detecting FRP and their damage/defects in FRP-RSC elements. This study further investigates the feasibility of two new methods for improving the detectability of embedded FRP bars. By providing the inspection community with more clarity in the application of NDT to FRP, this study offers means for verifying the performance and, therefore, help the proliferation of FRP materials in concrete structures.

Ultra-wideband microwave leakage monitoring for stringer debonding detection in carbon composite fuselage structures

Ultra-wideband guided electromagnetic waves have been proposed recently for non-destructive testing and structural health monitoring applications. However, many possibilities are still unexplored given by the multitude of possible microwave waveguides. The present work introduces the concept of microwave leakage monitoring to detect stringer debondings in hollow carbon composite structures. The principle is to monitor the wave propagation characteristics within the cavity formed by the stringer and the airframe skin using transmission measurements. Changes in the transmission path, e.g. occurring from microwave leakage in the debonded region, can be assessed through a damage indicator approach.To proof this concept, an experimental campaign was carried out according to the building block approach typically used in aeronautics. First, a small-scale specimen with a debonded stringer was investigated in the laboratory. Then, a large-scale fuselage structure was used for technology demonstration enabling stringer debonding with increasing severity through static and fatigue loading. The paper shows that the microwave characteristics in the waveguide (stringer tunnel) is affected by the debonding conditions according to its severity and depth. This allows designing a structural health monitoring system based on guided electromagnetic waves trapped in the tunnel.

Scientometric Analysis of the Dynamics of Artificial Intelligence Applications in NonDestructive Testing and Structural Integrity Monitoring

This study aims to present a scientometric analysis of Artificial Intelligence (AI) applications in NonDestructive Testing and Evaluation (NDT&E) and Structural Integrity Monitoring. The data is collected from the research papers contained in the Web of Science Core Collection, covering studies on AI applications in various NDT methods employed across different industry sectors. The collected 654 research articles-dataset published between April 1989 and January 2023 was processed using CiteSpace software, which classified the dataset into twelve clusters. Moreover, a subset of the data pertaining to the relevant research in the nuclear industry was considered for analysis. Various metrics were used to analyse the consistency of the clusters and publications' influence and quality. The results, which quantify the dynamics and quality of research in AI for NDT&E, are given in visualised mappings, and tabulated data and the content of the major clusters was discussed to reveal the used AI and NDT&E methods and the sectors or industries where they have been used.

Accelerating a Meta Learning Model for Ultrasonic Non-Destructive Testing Applications Using Model Compression and FPGA Hardware

Accelerating a Meta Learning Model for Ultrasonic Non-Destructive Testing Applications Using Model Compression and FPGA Hardware

Coupling effect between highly nonlinear solitary waves and functionally graded porous plates reinforced with graphene platelets

ABSTRACT Solitary waves possess extensive potential for application in non-destructive testing due to their role as efficient information carriers. This study investigates the coupling effect between highly nonlinear solitary waves and functionally graded porous plates reinforced with graphene platelets (FGP-GPLs). An improved Halpin–Tsai micromechanics model and an improved two-variable precision plate theory are employed to derive a differential equation system for the coupling of particle chains and FGP-GPLs. The system is solved using the fourth-order Runge–Kutta method to obtain velocity and displacement solutions of the particles. The time and amplitude of the rebound waves are analysed, and it is found that the pore distribution, graphene distribution, porosity coefficient, thickness ratio, and graphene weight fraction impact the solitary wave. The results of this study provide a theoretical basis for the non-destructive detection of FGP-GPLs by solitary waves, which enables rapid inspection and controllability studies of structures. Moreover, this technology expands the application fields of nonlinear solitary waves based on one-dimensional spherical particle chains.

Concrete Non-destructive Testing Technology and Its Application

Nondestructive testing of concrete has a very important position in the construction industry, this paper explains the nondestructive testing, introduces the necessity of nondestructive testing in a number of aspects, classifies the nondestructive testing technology of concrete, introduces the characteristics of several types of nondestructive testing, explains the current application of nondestructive testing in various fields of construction, the problems of nondestructive testing.

A systematic tomography framework for thickness mapping of pipes using helical guided waves

Pipe wall loss caused by corrosion is of growing interest in the petrochemical industry. A systematic tomography framework using helical guided waves is developed in this paper to conduct a thickness mapping. In this work, the thickness under investigation is reconstructed using an objective function derived from the acoustic Helmholtz equation. The main approach consists of two parts. Firstly, the parametric dictionary is designed to separate the overlapped guided waves travelling in helical paths. After that, the scattering field can be extracted as the input of the distorted born iteration method. The imaging result is exemplified numerically and experimentally, with the strengths and drawbacks explained thoroughly. Remarkably, the thickness error of the simple defect is still within 0.5 mm when the input data is poor. A clear qualitative description of complex defects can be achieved through iterations even in the absence of an initial objective function. The framework established in this paper contributes a comprehensive imaging algorithm and the corresponding signal processing approach, all of which are conducive to providing some reference for engineering applications in nondestructive testing and structural health monitoring.

A robust adaptive-thresholding primal-dual sparse recovery for THz imaging

Terahertz time-domain spectroscopy (THz-TDS) system is a powerful tool in material spectral analysis and non-destructive testing (NDT). However, the data acquisition is time-consuming due to the point-by-point scanning process, which leads to limitations in THz imaging applications. In this paper, a robust adaptive-thresholding primal-dual sparse recovery (APSR) method is proposed to reconstruct high-resolution THz images and reduce the acquisition time. A sparsity averaging dictionary, which is a concatenate of multiple bases, is applied to improve the robustness and generalization. A reweighted scheme is also adopted to enhance the sparse solution. As a crucial consideration in the sparse recovery method, we propose a robust adaptive threshold estimator based on the median absolute deviation in the sense that the final threshold determines the reconstruction quality and the convergence rate. Meanwhile, together with the Nesterov acceleration technique, a large threshold can be applied at the beginning of the iteration to help accelerate the convergence. Numerical experiments demonstrate that the APSR method can reconstruct THz images with robustness even with low SNR (of 30 dB) and low sampling rate (of 30%) compared to conventional methods. In the real THz-TDS system, our proposed sparse imaging method can successfully recover a composite object with much fewer THz spectra and reduces the acquisition time to 30% at the cost of a relative error of 2.5%, demonstrating the efficiency of our proposed method and the penetrating ability of THz technology in the NDT applications.