The vibration-based damage identification techniques use changes in modal properties of structures to detect damages. However, the results of these methods are not reliable under noise. Therefore, it is essential to clarify which method performs vigorous under noisy conditions. In this study, three damage detection methods, called modal strain energy-based damage index, modal flexibility, and modal

Reinforced concrete bridges are iconic parts of modern infrastructure. They are designed for a minimum service life of 100 years. However, environmental factors and/or inappropriate use might cause overload and accelerate the deterioration of bridges. In extreme cases, bridges could collapse when necessary maintenance lacks. Thus, the permanent monitoring for structure health assessment has been proposed

The acoustic emission (AE) technique was employed to monitor crack formation in the water-saturated ceramic material subjected to freeze–thaw cycles. The samples with water accessible porosity ranging from 6 to 50 vol% were prepared from the illite-rich clay by the sacrificing template method. The experimental samples were fired to 1100 °C in the static air atmosphere. Afterward, they were saturated

This work focuses on the relation between the sphericity and compactness parameters obtained from the exhaustive analysis on the graphite nodules of a spheroidal graphite cast iron sample, in order to propose a methodology with allow establishing different quality categories of nodules. The experimental methodology involves X-ray micro-computed tomography on an ad hoc test sample to generate high-resolution

The hammering method used by inspectors is generally applied to inspection of looseness of bolted parts. This method entails active sensing through the input of an excitation signal produced by the inspectors, and has the advantage of practical experience acquired over many years. The sound (vibration) and sensation produced upon excitation by a hammer can be used as indices, but also leads to the

The semi-solid sintering of a novel Ti6Al4V/CoCrMo biomedical composite was investigated for the first time by semi-in situ X-ray computed microtomography. Composite was fabricated by dry mixing 15 vol% CoCrMo reinforcing particles with Ti6Al4V particles as matrix. The mixture was poured into a 1 mm diameter quartz capillary. 3D images of the same sample were acquired before and after sintering at

Cyber technologies are offering new horizons for quality control in manufacturing and safety assurance in-service of physical assets. The line between non-destructive evaluation (NDE) and Industry 4.0 is getting blurred since both are sensory data-driven domains. This multidisciplinary approach has led to the emergence of a new capability: NDE 4.0. The NDT community is coming together once again to

Convolutional neural networks were used for multiclass segmentation in thermal infrared face analysis. The principle is based on existing image-to-image translation approaches, where each pixel in an image is assigned to a class label. We show that established networks architectures can be trained for the task of multiclass face analysis in thermal infrared. Created class annotations consisted of pixel-accurate

Spectral CT can separate basis materials, and thus it can provide information on material characterization and quantification. Such information can benefit various clinical applications. However, the presence of non-ideal effects in X-ray imaging systems limits the accuracy of basis images. To achieve high accuracy of material decomposition and high quality of basis images, a novel direct iterative

Film quality analysis is of more considerable significance due to its diversified applications in various fields of technology. The present work reports the speckle interferometric analysis of the argon pressure-induced surface roughness modifications of RF sputtered MoO3 films. The paper suggests a new method of surface quality analysis of thin films through a parameter δ, which is the difference

The spread of additive technologies from prototyping to manufacturing has made the development of new products possible, but still needs effective methods in order to allow their characterization. In particular, porosity is considered a crucial aspect of AM products. A prototype system for the deposition of continuous carbon fiber-reinforced polymers with a thermoplastic matrix has been recently developed

Flaw detection in non-destructive testing, especially for complex signals like ultrasonic data, has thus far relied heavily on the expertise and judgement of trained human inspectors. While automated systems have been used for a long time, these have mostly been limited to using simple decision automation, such as signal amplitude threshold. The recent advances in various machine learning algorithms

Construction of drilled shafts for transportation infrastructure presents quality assurance challenges related to structural anomalies, including voids and degraded concrete. Efforts to evaluate anomalies often use stress-wave non-destructive testing (NDT) techniques such as the crosshole sonic logging (CSL) method. CSL relies on the propagation of stress waves between access tubes inserted alongside

Thin-walled tubes and pipes are employed in industries to work under the conditions of high temperature, high pressure, high flow rates and radiation. Due to such stresses and harsh working conditions, tubes lead to sag during operation because of its low Wall Thickness and smaller diameters. There is a requirement to accurately measure sag and dimensions and assess the health and remaining life of

XXL-Computed Tomography (XXL-CT) is able to produce large scale volume datasets of scanned objects such as crash tested cars, sea and aircraft containers or cultural heritage objects. The acquired image data consists of volumes of up to and above \(\hbox {10,000}^{3}\) voxels which can relate up to many terabytes in file size and can contain multiple 10,000 of different entities of depicted objects

This study aims to evaluate coating adhesion durability using the laser shock-wave adhesion test (LaSAT). In particular, the interfacial strength with respect to the applied loading cycle is evaluated quantitatively. This method uses strong elastic waves induced by pulsed laser irradiation, as interfacial fracture of the coating occurs due to a strong wave. The coating delamination can be identified

Selective electron beam melting (SEBM) is an additive manufacturing process for the production of complex metallic parts. To optimize their mechanical properties, pores and fusion defects, since not completely avoidable, have to be detected and evaluated. The generated microstructure may contain not only voids, but also weak bonds, sharp interfaces and loose particles causing nonlinear elasticity.

Wire rope inspection by nondestructive testing methods, sensors and signal processing techniques are mainly reviewed in this paper. Owing to the difference of physical mechanism and testing principles, magnetic flux leakage, eddy current, acoustic emission and ultrasonic guide wave testing as well as other inspection methods for steel wire rope are summarized. Then, the commonly and frequently used

The flexible printed coil array (FPC) is employed extensively because of its flexibility in non-destructive testing (NDT). To make the inductive coil detect both external and internal defects under static conditions in magnetic flux leakage testing (MFL), this paper proposes a method based on the AC and DC composite magnetization. The AC magnetization changes the magnetic field strength in the vicinity

Stresses have great influences on the mechanical performance and corrosion resistance of pipelines. Magnetic Barkhausen noise (MBN) as an effective non-destructive testing method for evaluating stress in ferromagnetic materials has been widely studied in recent decades. Different from traditional MBN methods based on a time-varying magnetic field, this paper proposed a novel MBN method to induce Barkhausen

In this study, the physical foundations of the combined acoustic-electric method are examined for testing layered materials, as well as materials with defects in the form of solid inclusions. The numerical simulation results of the electromagnetic signals excited in a test material via pulsed acoustic impact are presented. The effect of sample layering on the electromagnetic response parameters under

The uniaxial compressive strength (UCS) is considered as a significant parameter related to rock material in design of geotechnical structures connected to the rock mass. Determining UCS values in laboratory is costly and time consuming, hence, its indirect determination through use of rock index tests is of a great interest and advantage. This study presents a prediction process of the UCS values

The knowledge of grain growth directions makes it possible to describe the material anisotropy, which helps to ensure the ultrasonic testing of welded assemblies and the assessment of their mechanical integrity. Here, we study multipass welds made of 316 L stainless steel manufactured by a Gas Tungsten Arc Welding (GTAW) process. We have developed a specific model to predict the grain growth directions

Electrical impedance tomography (EIT) uses non-invasive and non-radiative imaging to detect inhomogeneous electrical properties in tissues. The inverse problem of EIT is a highly nonlinear, ill-posed problem, which causes inaccuracy in target size calculation. We propose a novel approach to discretize the target size and use a neural network (NN) classifier to classify the unknown size in discrete

An artificial neural network (ANN) model and response surface methodology (RSM) were established to estimate the compressive strength of concrete by using the combination of three non-destructive tests (NDT); rebound number, pulse velocity tests and resistance surface. These techniques are utilized in an attempt to increase the reliability of the non-destructive tests in detecting the strength of concrete

Optical fibers (OFs) are among the most promising technologies for distributed sensing in structure health monitoring of composites. Optical backscatter reflectometer (OBR) based on Rayleigh scattering enable to use the entire length of telcom OF as sensor, giving detailed information about the stain fields in the host structure. Embedded sensors can provide many advantages over surface bonded ones

This paper presents a method for improved analysis of objects with an axial symmetry using X-ray Computed Tomography (CT). A cylindrical coordinate system about an axis fixed to the object’s center of symmetry forms the most natural base to analyze characteristics of those objects that exhibit axial symmetry, as is often the case for industrial parts. As the sampling grid in the proposed methodology

Technical advantages of additive manufacturing (AM) have drawn great attention over the past few years. This cost-effective manufacturing process proved its potential applications in a wide range of fields. Although AM techniques (known as 3D printing) are able to fabricate geometrically complex components, it is necessary to evaluate internal and external dimensions of the printed parts. In this context

Porosity is an unavoidable defect in carbon fiber reinforced polymers and has noticeable effects on mechanical properties since gas filled voids weaken the epoxy matrix. Pulsed thermography is advantageous because it is a non-contacting, non-destructive and fast photothermal testing method that allows the estimation of material parameters. Using the Virtual Wave Concept for thermography data, ultrasonic

Mid-infrared signals in the 2–5 μm wavelength range have been transmitted through samples of polymer pipes, as commonly used in the water supply industry. It is shown that simple through-transmission images can be obtained using a broad spectrum source and a suitable camera. This leads to the possibility of tomography, where images are obtained as the measurement system is rotated with respect to the

Due to its flexibility for use in various applications active thermography is of interest for non-destructive evaluation of defects in various materials. In particular, active thermography allows for identification of imperfections inside glue joints like delaminations, air pockets or inclusions of foreign particles. The contribution of this work is the development and validation of a small and portable

Nuclear material containment buildings are required to be periodically inspected to assure good quality conditions. To this end, there is increasing interest in developing efficient and economical testing techniques to monitor and inspect these structures. In this paper we study the dynamic behavior of a 1/3 mock-up containment structure and its internal pressure-dependence using testing techniques

Crack damage is commonly observed for civil structures and infrastructure in service. The recent years have witnessed an excessive utilization of deep learning models for realizing autonomous and machine-vision based crack detection. Given this trend, this paper recognizes two entwined challenges: the preparation of large-scale training data and the detection of simple crack damage amid complex scenes

This document provides a comparative evaluation of the performance of a deep learning network for different combinations of parameters and hyper-parameters. Although there are numerous studies that report on performance in deep learning networks for ordinary data sets, their performance on small data sets is much less evaluated. The objective of this work is to demonstrate that such a challenging small

Thanks to its good strength/mass ratio, a glass fibre reinforced plastic (GFRP) composite is a common material widely used in aviation, power production, automotive and other industries. In its turn, active infrared (IR) nondestructive testing (NDT) is a common inspection technique for detecting and characterizing structural defects in GFRP. Materials to be tested are typically subjected to optical

Sliding friction causes significant structural transformations in the subsurface layers of interacting materials. These changes are associated with complicated mechanochemical processes which include but not limited to plastic flow, refinement of structure, increase of dislocation density, oxidation, delamination and formation of wear debris. In this study we attempted to observe some of these processes

A damage identification scheme combining impact-synchronous modal analysis (ISMA) and artificial neural network is developed in this study. The ISMA de-noising method makes it feasible to detect and classify the damage states with high accuracy when the machine is under operation. The feed-forward backprop network was utilized in this study. The input feature vector of the network consisted of the

Parametric signal representation techniques with Chirplet models have attracted much attention in ultrasonic guided waves-based research of material property identification and structural integrity evaluation. The known Chirplet models are established using either the Gaussian windows or the linear chirp function. This is inconsistent with practical situations where the excitation is a Hanning-windowed

The degree of saturation (DoS) of moisture is the main parameter related to the durability of cement-based materials. In this paper, the electrical response of hardened cement paste is investigated at low radio frequency (RF) excitation. Cement paste samples with water to cement ratio (w/c) of 0.40 and 0.45 are used and the samples are conditioned to different DoS. A pulse-based electrical input is

Damage processes in glass fiber reinforced plastic composites have been examined extensively by many analytical and experimental methods, including acoustic emission. While damage phenomena in mezo- and macro-scale are well described, the subtle mechanisms in micro-scale are still under discussion. The goal of this work was to apply the acoustic emission to examine damage initiation in fiber reinforced

A planar stress-free boundary is known to destructively alter the nonlinear wave generation process including the second harmonic component. This is the reason why the harmonic generation measurements in the study of nonlinear fluids and solids have been limited to the through-transmission setup. Recently, we have found through acoustic modeling and simulation that a dual element transducer composed

We introduce an optimized physics-informed neural network (PINN) trained to solve the problem of identifying and characterizing a surface breaking crack in a metal plate. PINNs are neural networks that can combine data and physics in the learning process by adding the residuals of a system of partial differential equations to the loss function. Our PINNs is supervised with realistic ultrasonic surface

X-rays and gamma rays are used in industrial radiography to detect internal defects and different structures of the test object. The radiography interpreters must be able to evaluate and interpret the radiography images as accurately as possible. To improve the operator’s image perception and interpretation, the quality of radiographs can be enhanced by different image processing methods. In this study

Structural damage detection methods relying on laser-measured vibration shapes have become a research focus in the past decade. For damage in a beam/bar with reduced cross-sectional dimensions, such as a notch, it causes changes in both its bending stiffness and axial stiffness in the damage region. Such stiffness changes can induce discontinuities in derivatives of flexural and longitudinal vibration

Evaluation of deteriorating highway bridges requires new, rapid inspection methods to effectively guide repair in an era of limited fiscal resources. Of all the components of a bridge, the bridge deck typically deteriorates most quickly and must therefore be regularly inspected for non-visible internal cracking, called delamination, for which early detection and repair can enhance safety and performance

Sulfuric acid corrosion on concrete structures is more prevalent and its damage evaluation becomes gradually imperative. This study attempts to characterize the sulfuric acid corroded surfaces of concrete in terms of three-dimensional fractal dimension. Accelerated sulfuric acid corrosion tests were conducted using concrete cylinders with six different corrosion durations, and the 3D coordinates of

This paper presents a procedure for the evaluation of the conservation state and restoration efficiency of nineteenth century camorcanna vaults based on the analysis of objective features extrapolated from non-destructive vibration testing data. The camorcanna vault in “Salone Grande” of the ninteenth century Villa Greppi in Monticello Brianza, near Milan, Italy, was chosen as an application example

The aim of this work is the development and experimental implementation of the laser-ultrasonic method for CFRPs porosity assessment with one-side access to an investigated object. The scheme with the laser thermooptical generation and backward-mode piezoelectric detection of longitudinal acoustic waves is used. The proposed method is based on the measurement of the acoustic impedance of a composite

Traditional ultrasonic imaging inspection does not perform well for austenitic welds, in which the defect locating accuracy is insufficient due to the distortion of propagation paths caused by the weld’s anisotropy and inhomogeneity. The distribution of grain orientation (DGO) contributes to the velocity distribution in austenitic welds and influences the ultrasonic propagation paths. An improved ultrasonic

A graphic augmented defect recognition algorithm was developed for phased array ultrasonic testing (PAUT) on tubular TKY joints. Based on PAUT sector scan (S-scan), 2D maps of the scans are obtained in terms of signal intensity and locations using spatial clustering and segmentation. The transformed S-scan data was further mapped with weld geometrical model to discriminate defect indications from the

Steel pipes in process plant applications are often covered with insulation or weather protection that make inspection difficult because the additional layers need to be penetrated to inspect the pipes’ structure. The pulsed eddy current (PEC) method was devised as a means of inspection through the surface layers. However, the performance of a PEC system is dependent on the electrical and magnetic

The paper describes an algorithm developed to enhance the analysis (manual or automatic) of radiographic images acquired for samples of complex geometry (such as those enabled by additive manufacturing techniques), where the imprint of the sample’s geometric complexity in the radiograph is likely to undermine the ability to identify defect indications. The underlying premise is that, assuming the sample

This paper presents the use of a digital holographic vibrometer to investigate metal-polymer laminates by non-destructive testing. A polymer strip was glued to a metal one of the same size. Connection defects could be detected by a local change of the vibration amplitude, even when hidden from view for the observer. The amplitudes of the oscillations excited in the samples were up to 40 nm. This method

Despite sonic and ultrasonic tomography are major NDT techniques, the resolution and the capability of these tests could be substantially improved; this, especially for masonry structures. Moreover, although waves amplitude attenuation is strictly related to the internal features and to the defects, some experimental and theoretical issues obstruct practical applications of amplitude tomography for

In this paper, a method combining ultrasonic travel time measurement with inversion is proposed to reconstruct the solid temperature field. Based on the measured transient ultrasonic propagation time, the inverse problem of acoustic thermal coupling is solved directly, and the unknown equivalent heat flow is estimated. Then, the time and space distribution of the internal temperature field can be reconstructed

Damage detection and structural health monitoring using the electromechanical impedance method has been accepted as an effective technique between various approaches of nondestructive evaluation. Many efforts have been made on experimental methods for obtaining the impedance of structures. However, expensive experimental methods encourage researchers to develop theoretical models. In this paper, a

Hydrogen embrittlement (HE) of high-strength steels has been a long-standing issue in the aerospace industry. Detecting the presence of hydrogen in steel with a low-cost and fast non-destructive method would be useful to avoid wasting parts. In this paper, we evaluate the feasibility of using eddy currents to achieve this goal. At first, we evaluate HE and hydrogen content in a series of chromium-plated

Increasing the safety demands of various progressively complex structures (e.g., in aerospace, automotive engineering, and wind power technology) and the parallel goal of reducing inspection costs set new objectives in the field of ultrasonics and guided elastic wave measurements. The focus is to deliver applicable sensors attached permanently to a particular structure for on-demand inspections. Piezoelectric

Transverse matrix cracking is probably the first and most dominant mode of damage in composite materials. In this paper, a real-time Non-Destructive Testing (NDT) method was proposed to detect the transverse cracks by Fiber Bragg Grating (FBG) sensors. The experiment of observing the crack growth and recording FBG’s reflection spectrums as well as Finite Element Method (FEM) methods were conducted

More than 20 years of research progress regarding the nondestructive testing method of metal magnetic memory is reviewed and summarized in detail. Consequently, this overview is selective, covering what we feel are the most important trends of experimental phenomena, mechanism explanations, quantitative theories, simulations, testing, evaluation and application. From analyzing the current state of