bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact localization in composite structures with guided wave and 1D convolutional neural network
Authors:   Huazhong University of Science and Technology, Feng Bo ,   Changjiang River Scientific Research Institute, Zhang Jikai ,   Huazhong University of Science and Technology, Chen Shukai ,   Huazhong University of Science and Technology, Liang Hanjie ,   Huazhong University of Science and Technology, Kang Yihua
Published: July 2023

Low velocity impacts may cause damages to the composite material. Piezoelectric transducers can be mounted onto the plate surface to monitor the impact by recording the impact induced guided waves. In this study, an impact localization algorithm based on 1D convolutional neural network is proposed. To test the effectiveness of the proposed algorithm, 4 PZTs were glued to a composite plate to monitor a region of 200 mm × 200 mm, and an impact experiment was conducted by dropping a glass ball at 117 different locations on the plate. The time-domain guided wave signals obtained by 4 PZTs were used as input to the 1D convolutional neural network. The output of the network was the coordinates of impact. The trained network was afterwards applied to locate impacts at unseen locations, and the mean localization error is 15.2 mm.
Phased-Array Approach to Air-coupled Ultrasound with Resonant Defect Excitation
Authors:   University of Stuttgart, Reindl Timo ,   University of Stuttgart, Bernhardt Yannick ,   CAE Software und Systems GmbH, Kohn Kai-Uwe ,   University of Stuttgart, Kreutzbruck Marc
Published: July 2023

Wave propagation in air-coupled ultrasound (ACUT) is slower compared to ultrasound in immersion technique. Due to the lower velocity of sound the maximum pulse repetition rate is five times smaller than in water coupled ultrasound. This can be compensated when using parallel transducers and receivers. For example, with five transducers a similar scanning rate can be achieved like in water based immersion technique. Further, the use of multiple probes allows for additional ways of testing. With beamforming, for example, it is possible to focus on specific spots of the specimen. In this work, a set-up with a 72 channel acoustic camera with broadband microphones and a frequency maximum at 80 kHz was used. Detection of the loudest source is easily possible with an acoustic camera using beam forming algorithms. By exciting the whole specimen with a single piezoshaker over a broad frequency range, it was possible to excite the resonant frequency of the defects, which makes the detection with an acoustic camera even more faster. With this method it took less than 1 s to scan an area of 300 mm x 300 mm of a glass fiber reinforced plastic part and find a damaged area.
High Temperature Characterization of the Stiffness Matrix of Different Steels
Authors:   TNO Science & Industry, Volker Arno ,   Swerim AB, Malmström Mikael ,   Swerim AB, Jansson Anton ,   Swerim AB, Hutchinson Bevis ,   Swerim AB, Lönnqvist Johan ,   SSAB Europe, Sollander Hans ,   Tata Steel, Van Den Berg Frenk
Published: July 2023

The aim of this work is to acquire material data at elevated temperatures for different chemical compositions and phases as basis for numerical simulations incorporating the effect of crystalline texture. Several samples; AISI 304, interstitially free, low carbon, martensite, and pearlite, were measured in a Gleeble® Thermal-Mechanical Simulator 3800 in conjunction with LUS (GLUS®) during annealing from room temperature up to a maximum temperature in the range between 675 and 1000 °C. The laser ultrasonic measurements contain both pressure (P) and shear (S) waves. The arrival time of at least the first S-wave echo and two or more P-wave echoes were used. From the measurements it was observed that there was a slight tilt of the sample and misalignment of the centres of the generation and detection laser beams. An inversion scheme was implemented estimating the nine stiffness coefficients as well as the sample tilt and alignment error. The estimated stiffness coefficients as a function of temperature were successfully obtained from the measurements. Most of the coefficients decrease with increasing temperature, whereas C12, C13, and C23 remain relatively constant. The implemented inversion scheme successfully compensates for sample tilt and laser misalignment.
Acoustic non-destructive testing of UAS´s propellers during predeparture and post-flight checks
Authors:   German Aerospace Center (DLR), Soria Gomez Maria ,   German Aerospace Center (DLR), Koschlik Ann-Kathrin ,   German Aerospace Center (DLR), Arts Emy ,   German Aerospace Center (DLR), Raddatz Florian ,   German Aerospace Center (DLR), Wende Gerko
Published: July 2023

Unmanned Aerial System (UAS) activities have increased steeply in the last years, market research forecasts a continuous increase in the near future. The rapid growth of this industry, however, has outpaced the development of rules and systems to govern their use, as well as those to ensure a safe operation before, during and after flight. Maintenance, Repair and Overhaul (MRO) aspects will gain relevance as more and more UAS take to the sky. Rotary-wing UAS have 2 or more propellers, which are easily damaged during normal operation of the vehicle. The reduced thrust and increased vibration imply losing performance and setting the UAS structure under stress. With the propellers being the main source of sound of the propulsion system, we propose the use of acoustics to identify damaged propellers. Microphones placed off-board do neither disrupt UAS operation nor reduce the payload capacity. Furthermore, this method does not depend on a particular manufacturer or software. In this paper, we present a concept for the non-destructive testing of multi-copter propellers. The fault diagnosis aims at recognizing the difference in sound between damaged and undamaged propellers. This evaluation takes place before the UAS takes off the ground and after it lands, thus allowing to interrupt a possible dangerous mission or identifying damage occurred during operation. The vehicle is on the ground in an “idle state” where the propellers already spin, but not fast enough to lift it. This state is used for a first analysis of the sound of a single propeller and several propellers, as well as for the generation of data. Next, two approaches for the detection of damage are developed and their performance is evaluated: an analytical approach and a machine learning algorithm based on an autoencoder neural network....
Artificial Intelligence for Assisted Analysis of Eddy Current Data from Heat Exchangers with Non-Ferromagnetic Tubes
Authors:   Eddyfi Technologies, Provençal Etienne ,   Eddyfi Technologies, Sisto Marco Michele ,   Eddyfi Technologies, Veilleux David ,   Eddyfi Technologies, Grenier Marc
Published: July 2023

Oil & Gas and petrochemical industries need regular inspection of shell and tube heat exchangers to maintain performance. NDT inspection service providers are required to complete the data collection and analysis in the shortest possible time frame, but manual analysis for defects like corrosion or pitting is time-consuming and prone to errors. This leads to safety risks and unexpected downtime, and there's a shortage of experienced ECT level II/III certified analysts globally. The industry needs tools to simplify data interpretation and increase analysis efficiency while maintaining a consistent and repeatable level of confidence. While assisted analysis for tube ECT testing has existed for several years, most solutions have been developed for the nuclear industry and employ methods that become quickly limited when the test conditions are not well controlled or when the tube bundle information is incomplete These situations are very common outside the nuclear industry, and they often contribute to reducing the efficiency and reliability of data interpretation. This communication outlines the use of AI in various tasks of tube data analysis, from landmark localization to indication detection, to improve efficiency and confidence in the analysis process. A complete analysis system has been implemented and field data results demonstrate the system's value. Robustness to suboptimal data quality is also discussed.
Detection of defects initiation in weld joints
Authors:   Research Centre Rez, Mareš Pavel ,   Research Centre Rez, Veselá Jana
Published: July 2023

Welded joints on various pipelines, especially steam pipelines of fossil power plants, are exposed to high pressure and temperature of steam during operation. The applied stress and temperature together with the chemical composition and microstructure of the material have a major influence on the damage growth in these joints. Growth of defects as a time-dependent event, the sensitivity of the material to damage due to stress temperature and others plays a major role. In the case of steam pipes of fossil power plants, this is mainly creep damage. Early detection of these defects, especially at their initial stage, can help in managing the service life and thereby reducing the costs for operation, both by minimizing unplanned shutdowns as well as by planning any repairs in time. The work is focused on the detection of defect indications, especially creep damage occurring in weld joints and heat-affected areas. The aim is to distinguish manufacturing defects of welded joints from indications of early crack growth by ultrasonic testing. Indications from manufacturing defects may also be detected during testing and, if detected, will be evaluated in the same way as defects that are primarily targeted by the testing techniques. Several different techniques were tested on samples cut from the operated steam pipeline systems and compared with the results of metallographic analyses on selected parts.
Comparison of grain structure models for wave propagation analysis in centrifugally cast stainless steel
Authors:   Central Research Institute of Electric Power Industry (CRIEPI), Nagai Masaki ,   Akita University, Natsume Yukinobu ,   Central Research Institute of Electric Power Industry (CRIEPI), Lin Shan
Published: July 2023

Centrifugally cast stainless steel (CASS) is widely used in primary coolant piping of pressurized water reactor plants because of its high corrosion resistance and high strength. An in-service inspection based on ultrasonic testing (UT) has to be conducted for weld joints of primary coolant piping on the basis of JSME Rules on Fitness-forService for Nuclear Power Plants. However, it is difficult to detect and size flaws in CASS components with high accuracy because of the following reasons: Ultrasonic waves are scattered and attenuated due to coarse grains, and anisotropic and heterogeneous properties in CASS lead to ultrasonic beam skewing. Numerical simulations are useful and reasonable ways for better understanding the ultrasonic wave propagation behavior in CASS. To effectively achieve this, the simulation model should include a three-dimensional (3D) grain structure. In this study, we modeled three kinds of the solidification grain structures of centrifugally CASS. One is obtained by using a cellular automaton method, another consists of many hexagonal columns with the same dimensions, and the other is transversely isotropic material. Then these structures were fed into an explicit finite element model for simulating wave propagation and the simulated results were compared with those measured by a laser Doppler vibrometer. Through the comparison, we investigated the applicability of these three kinds of solidification grain structure models to simulation for wave propagation.
Non-contact assessment of porosity in metal 3D printed parts by vibration spectra
Authors:   Institute of Electronics and Computer Sciences, Tatarinov Alexey ,   2AM SIA (Ltd.), Nikolas Alexey ,   Institute of Electronics and Computer Sciences, Nikulenkov Vladimir ,   Riga Technical University, Zemchenkovs Vyacheslavs ,   Riga Technical University, Kuzmina Jekaterina ,   Riga Technical University, Mironovs Viktors
Published: July 2023

Volumetric porosity as a common defect in metal 3D printing (3DP) that can significantly impede the mechanical properties of products. Traditional methods of porosity control (microscopy) and non-destructive testing (computed tomography) usually are not applicable at the production site. In this study, sensitivity of three examined testing modalities based on acoustic methods and vibration analysis to changes in the volumetric porosity of 3DP parts was examined. Test objects were cylindrical specimens made of AlMg powder by 3DP with a gradually dosed porosity from 0.5 to 4.0%. Ultrasonic testing by through transmission showed the best accuracy using ultrasound velocity and pulse intensity parameters. Shifts of resonant frequency and spectral density and appearance of side harmonics were the manifestations of increased porosity using vibration approaches. The method comprising a loudspeaker as a vibration exciter and an optoelectronic device for remote sensing of vibration is the most attractive from the point of view of application to objects of complex geometry.
Temperature-Controlled in-situ Tensile Tests of Polymer Tape with Single Particles
Authors:   Upper Austrian University of Applied Sciences (FH OÖ), Heupl Sarah ,   Upper Austrian University of Applied Sciences (FH OÖ), Maurer Julia ,   Upper Austrian University of Applied Sciences (FH OÖ), Kastner Johann
Published: July 2023

X-ray Computed Tomography (CT) combined with mechanical testing can deliver great insights in the damage mechanisms of polymers. Depending on the application area of the polymer, temperatures can be very high or low – leading to a different performance compared to room temperature. In this study, the influence of the temperature on damage mechanisms of a single particle in a polymer matrix should be investigated. Thus, three polymer tensile test specimens (length 30 mm; width 10 mm) – each containing a single particle – were cut out of a tape with a thickness of 0.5 mm and tested at various inspection temperatures. CT measurements were performed with the RX Solutions Easytom 160 laboratory CT device with a voxel size of (3 µm)³. Each specimen was scanned twice, namely at 0% strain and 30% strain. As inspection temperatures 0 °C, 22 °C and 60 °C were chosen. It is shown that temperature can have a great impact on the performance and damage mechanisms of a polymer, especially if a particle is present in the polymer matrix.
Defect-aware Super-resolution Thermography by Adversarial Learning
Authors:   University of Groningen, Liangliang Cheng ,   University of Ghent (UGent), Mathias Kersemans
Published: July 2023

Infrared thermography is a valuable non-destructive tool for inspection of materials. It measures the surface temperature evolution, from which hidden defects may be detected. Yet, thermal cameras typically have a low native spatial resolution resulting in a blurry and low-quality thermal image sequence and videos. In this study, a novel adversarial deep learning framework, called Dual-IRT-GAN, is proposed for performing super-resolution tasks. The proposed Dual-IRT-GAN attempts to achieve the objective of improving local texture details, as well as highlighting defective regions. The generated high-resolution images are then delivered to the discriminator for adversarial training using GAN's framework. The proposed Dual-IRT-GAN model, which is trained on an exclusive virtual dataset, is demonstrated on experimental thermographic data obtained from fibre reinforced polymers having a variety of defect types, sizes, and depths. The obtained results show its high performance in maintaining background colour consistency and removing undesired noise, and in highlighting defect zones with finer detailed textures in highresolution.
Development and adaptation of Ultrasonic system for Windblades inspection using Unmanned Aerial Vehicles
Authors:   Center for Advanced Aerospace Technologies (FADA-CATEC), Vilches Celia ,   Center for Advanced Aerospace Technologies (FADA-CATEC), González Sergio ,   Center for Advanced Aerospace Technologies (FADA-CATEC), Trujillo Migue A. ,   Center for Advanced Aerospace Technologies (FADA-CATEC), Lasagni Fernando ,   Center for Advanced Aerospace Technologies (FADA-CATEC), Viguria Antidio ,   Center for Advanced Aerospace Technologies (FADA-CATEC), Ollero A.
Published: July 2023

Europe is facing one of the most challenging decades with the decarbonization of the energy generation. The increase in the use of energy from renewable sources is essential for the climate and energy global goals. In this way, the optimization of maintenance and repair works of the involved production systems is necessary to reduce costs and time of operation, especially in wind farms, where accessibility is reduced and usually dangerous. For this reason, novel technologies and applications are being investigated in the O&M field like the use of unmanned aerial vehicles (UAVs) for structural assessment of wind blade components through non-destructive technologies (NDT). This is the main goal of DURABLE project, where this investigation is framed. This work is focused on the comparative analysis of different ultrasonic technologies and the development of a protocol for the inspections of wind blades for its application by means of aerial vehicles. The inspections tests have been conducted on samples at laboratory level as a previous work for the post implementation of this technology with drones in field. Diverse UT transducers with 4.0 to 5.0 MHz emission frequencies as well as single element and phased array probes have been used to determine the best configuration for the inspection of each material and thickness of wind blades. To characterize the detectability, artificial defects (impacts and flat-bottomed drills) have been introduced in the test samples to analyze the detectability with manual handled UT inspections. Finally, the most suitable ultrasonic probe was selected, adapted and integrated in an end effector for its implementation in a UAV. The applicability of the inspection by using aerial vehicles has been tested in relevant environment (at laboratory) and in real windfarm.
Detection of barely visible impact damage in composite plates using non-linear pump-probe technique
Authors:   University Paris-Saclay, Ribay Guillemette ,   University Paris-Saclay, Mesnil Olivier ,   University Paris-Saclay, Noury Robin ,   SAFRAN Tech, Hadjria Rafik ,   SAFRAN Tech, d'Almeida Oscar
Published: July 2023

In the last decades, composite materials have been increasingly used in aircraft structures as a mean to reduce the weight. For safety reasons, periodic checks of impact-induced damage need to be performed. In that framework, ultrasound non destructive testing has proven its ability to detect macro-defects such as delamination. However, at early stages, Barely Visible Impact Damage (BVID) may not be detected via linear ultrasound techniques. In recent years, non-linear ultrasound has gained traction for the inspection of such defects. However, detection of the weak non-linear defect signature buried in ambient noise remains challenging, and depends on an empirical choice of excitation frequencies. This study focuses on the evaluation of a non-linear pump probe ultrasound inspection technique applied to BVID in multilayer carbon fibre reinforced composites used in aeronautics. In particular, the influence of various experimental parameters on the measured non-linear response is studied. A low frequency pump wave (via a shaker) and a high frequency wave (via a piezoelectric transducer) are transmitted to the medium while a second transducer records the ultrasonic response. Both pump and probe waves are sent in the form of a few secondslong frequency sweep, in the audible and ultrasonic range respectively. Appropriate post processing is then applied to the recorded signals to retrieve the non-linear response of the defect. The procedure is repeated on several composite plates with and without impact damages. The nonlinear response appears in the form of modulation sidebands in the frequency spectrum of the post-processed signals. The relative amplitudes of the side bands obtained for the various samples with various defect sizes and excitation amplitude or frequency content are studied. Optimal experimental parameters were obtained and led to a good detection of defects. The limits of the method are also discussed.
A data-driven method for the correction of optical distortions of depth cameras in immersion NDT
Authors:   Federal University of Technology (UTFPR), Trento Jr. Everton ,   Petrobras Research Center, Pires Gustavo P. ,   Federal University of Technology (UTFPR), Guarneri Giovanni A. ,   Federal University of Technology (UTFPR), Passarin Thiago Alberto Rigo ,   Federal University of Technology (UTFPR), Pipa Daniel Rodrigues
Published: July 2023

Stereoscopic cameras, also known as depth cameras, are increasingly present in robotics

navigation and 3D scene reconstruction. Normally, off-the-shelf depth cameras are not

suited for underwater environments and exhibit considerable distortions in the provided 3D images when operating underwater. This is mainly due to the large difference

in the refractive coefficients of air and water. This issue prevents their use in subsea

applications such as the inspection of oil pipelines, valves and manifolds, where these

devices could be used for odometry during ultrasonic inspections as well as for 3D scanning. Aiming to allow for such applications, we present a data-driven method for the

correction of distortions caused by unaccounted diffractions in depth cameras. First,

the distortion is modelled via a series of detections of control points from a standard

target at known underwater positions, and an approximation of the inverse distortion

is obtained. Then, at runtime, a procedure takes as input the (distorted) point cloud

given by the camera at each frame, applies the inverse distortion, and yields a corrected

point cloud. We apply the method to data provided by a RealSense D405 camera encased in a sealed acrylic container underwater. The correction makes it possible to use

the camera for odometry underwater, clearing the path for the use of off-the-shelf depth

cameras in a wide range of subsea applications. The method can be applied for any

other transparent fluid.
Full Waveform Inversion for NDT using ultrasonic linear arrays
Authors:   Federal University of Technology (UTFPR), Rossato Daniel ,   Federal University of Technology (UTFPR), Gutierrez Felipe Derewlany ,   Federal University of Technology (UTFPR), Guarneri Giovanni A. ,   Federal University of Technology (UTFPR), Passarin Thiago Alberto Rigo ,   Petrobras Research Center, Pires Gustavo P. ,   Federal University of Technology (UTFPR), Pipa Daniel Rodrigues
Published: July 2023

Ultrasonic (UT) imaging is a widespread technique for nondestructive testing (NDT).

The state-of-the-art UT image reconstruction algorithms are based on delay-and-sum

(DAS) operations, which assume constant acoustic velocity across the tested objects and

also neglects nonlinear effects such as diffractions and multiple reflections. These assumptions limit the reconstruction capabilities of DAS-based algorithms, especially for

complex objects composed by several materials. In seismology, Full Waveform Inversion

(FWI) methods have been used to obtain subsurface properties based on scattered and

transmitted sound waves - which is a very similar problem to ultrasonic imaging in NDT

- using the full wave information, showing promising results. In this paper, we present

the application of FWI in NDT using simulated data representing acquisitions with a

common linear array transducer. We review the theoretical formulation of FWI and discuss some difficulties that arise when it is applied to NDT. Image reconstruction is performed using both a state-of-the-art DAS algorithm, namely the Total Focusing Method,

and FWI. The implementation targets a GPU platform, using the CUDA API. This leverages the highly parallelizable nature of the simulations and the FWI algorithm. The

obtained results show that FWI can show more internal structures than TFM, with less

information about the specimen. To foster further development, all source codes are

provided.
Using Perfectly Matched Layer in a GPU simulation of ultrasound NDT
Authors:   Federal University of Technology (UTFPR), Gutierrez Felipe Derewlany ,   Federal University of Technology (UTFPR), Rossato Daniel ,   Petrobras Research Center, Pires Gustavo P. ,   Federal University of Technology (UTFPR), Passarin Thiago Alberto Rigo ,   Federal University of Technology (UTFPR), Guarneri Giovanni A. ,   Federal University of Technology (UTFPR), Pipa Daniel Rodrigues
Published: July 2023

Full Waveform Inversion (FWI) is a state-of-the-art method of image reconstruction

with promising results for seismology and NDT. FWI estimates the velocity of wave

propagation along the inspected object by iteratively comparing acquired data with

simulated data. This method is computationally demanding as at least three simulations

are needed per iteration, which motivates the research effort for fast simulation methods.

When simulating acoustic waves within a finite domain, artificial reflections created

at the boundaries yield unrepresentative signal acquisition in the simulation. These

reflections disturb the computation of residuals in FWI, creating artifacts that result

in inaccurate positioning of flaws and discontinuities. Various absorbing boundary

conditions (ABCs) have been proposed to avoid these reflections, e.g., Higdon, Reynolds,

and Perfectly Matched Layers (PML). Although Reynolds and Higdon have been used in

other applications, they are not well suited for FWI for reasons such as weak absorption

rate and excessive introduction of amplitude errors. On the other hand, the PML method,

an ABC that gradually attenuates boundary reflections with the addition of layers with

matched acoustic impedance, provides adequate attenuation for FWI and can be readily

extended to elastic waves. In this work, we describe an implementation of PML in

a parallel GPU-accelerated CUDA simulator, which is intended to be integrated into

an FWI regression in future works. Finally, we provide examples demonstrating that

PML can significantly reduce the domain of simulation of an ultrasound NDT while

maintaining simulation accuracy.
A WebGPU-based acoustic wave simulator for ultrasound NDT
Authors:   Federal University of Technology (UTFPR), Galera André P. ,   Federal University of Technology (UTFPR), Rossato Daniel ,   Federal University of Technology (UTFPR), Gutierrez Felipe Derewlany ,   Petrobras Research Center, Pires Gustavo P. ,   Federal University of Technology (UTFPR), Passarin Thiago Alberto Rigo ,   Federal University of Technology (UTFPR), Guarneri Giovanni A. ,   Federal University of Technology (UTFPR), Pipa Daniel Rodrigues
Published: July 2023

Ultrasound NDT is a standard industrial technique for health monitoring and flaw identification in several structures, such as subsea oil pipelines. Its primary purpose is to

form a representative image of the internal structure of the inspected object, which provides, in many cases, early warning of structure discontinuities, making it possible to

reduce repair costs and mitigate risks. One of the imaging methods that has been receiving increasing attention in the ultrasound and seismology communities is the Full

Waveform Inversion (FWI), which estimates the velocity model for the inspection area

by confronting the acquired information obtained by the NDT system with theoretical

simulated data. Since FWI algorithms rely on successive ultrasonic wave simulations, it

is essential to ensure that each simulation is optimized and contributes little to the total

running time. Acoustic wave simulations can be optimized using a graphical processing unit (GPU), which provides hardware acceleration through parallelism, where each

point of the simulated area can be computed simultaneously. Among all available GPU

APIs, WebGPU is the next-generation standard graphics Web API that exposes modern

computer graphics capabilities by giving the user low-level, general-purpose access to

the GPUs. This API is designed to efficiently map to native GPU APIs, which enables

applications to run on different GPUs, making implementations more scalable and interchangeable. Motivated by this flexibility, we explore the acceleration capabilities of

the WebGPU API by implementing a WebGPU-based acoustic wave simulator for ultrasound NDT.
Reliability Analysis of Pipe Wall Thinning based on Quantification of Ultrasonic Testing
Authors:   Tohoku University, Ikeda Kantaro ,   Tohoku University, Yusa Noritaka ,   Tohoku University, Tomizawa Takuma ,   Tohoku University, Song Haicheng
Published: July 2023

Piping in nuclear power plants is subject to corrosion and erosion caused by the interaction with fluids it carries. In order to prevent accidents such as pipe rupture, it is necessary to non-destructively inspect the thickness of the pipe wall and predict the remaining pipe life. In contrast, signals obtained by non-destructive inspection are affected by various uncontrollable and unknown factors, which will result in uncertainty in evaluating pipe wall thickness. Ignoring the uncertainty would lead to a large error in the pipe reliability assessment. Therefore, it is important to develop a reasonable pipe wall thinning management that can takes the uncertainty of non-destructive testing into consideration. Based on this background, this study aimed to develop a piping wall thinning prediction model that accounts for the uncertainty in evaluating pipe wall thickness and to evaluate its applicability to ultrasonic testing. At first, ultrasonic tests were performed to measure the thickness of specimens simulating flow accelerated corrosion. The results of the measurements were statistically analysed to obtain a mathematical model correlating the evaluated and true thickness. A numerical model to predict the reduction of wall thinning with its uncertainty is developed. Compared to the conventional method, the proposed method is able to predict wall thickness with high accuracy.
Automatic defect detection in fiber-reinforced polymer matrix composites using thermographic vision data
Authors:   NOVA University of Lisbon, Maria S. Gonçalves ,   NOVA University of Lisbon, Machado Miguel A. ,   NOVA University of Lisbon, Santos Telmo G. ,   NOVA University of Lisbon, Mendes Nuno
Published: July 2023

The detection of internal defects, not visible to the naked eye from the outside of

materials, using non-destructive testing (NDT) are increasingly requested by industrial

processes. This study proposes a novel methodology for acquisition and processing of

images from a thermographic camera using computer vision methods to test composite

materials made of a polymer matrix reinforced with glass, carbon, and kevlar fibers. The

image is acquired while cooling the sample, following a suggested procedure. The

processing methodology is divided into three steps, image pre-processing, image

processing, and data post-processing. In image preprocessing, filters are applied to

improve image quality, and methods are proposed to segment and identify the region of

interest. In image processing, a blob analysis method is suggested for defect

identification, isolation and characterization. A data analysis method is proposed for the

post-processing step to characterize the defects identified in the previous step. Samples

with known defects in terms of size, geometry, and location were used to test the

developed system. The system showed high performance, achieving 98% accuracy, and

suitability for defect detection larger than 0.5 mm in thickness and 600 mm2 in area. The

experimental results showed that the algorithm did not detect any false positives, and that

the type of reinforcement used in the analyzed samples had no influence on the results.

On the other hand, the depth of the delaminations had an influence on the pixel intensity

contrast of the defect region, and its instant of maximum contrast. The lesser the depth of

the defects detected, the higher the value of their intensity and the shorter the instant of

maximum contrast.
Automated woven background removal for enhanced infrared thermographic inspection of fabric composites
Authors:   University of Ghent (UGent), Poelman Gaétan ,   University of Ghent (UGent), Hedayatrasa Saeid ,   University of Ghent (UGent), Kersemans Mathias
Published: July 2023

Infrared thermography is a promising non-destructive testing methodology for the inspection of composite materials. While there are many accounts in literature that report an excellent performance on unidirectional composite laminates, this is not the case for woven fabric composites. Their inspection is typically characterised by the presence of an imprint of the weave pattern in the thermographic recordings, which is most-often found to be disturbing for reliable anomaly detection. In this contribution, it is proposed to evaluate the thermographic data in ????-space in order to separate the weave pattern from the defect information. To this end, an algorithm is introduced to automatically perform this decomposition. The efficiency of the proposed methodology is demonstrated for several weave patterns with different defect cases.
Automated misalignment correction method for ultrasonic inspection of CFRP parts
Authors:   Centre Technologique en Aérospatiale (CTA), Beausoleil Alexandre ,   Centre Technologique en Aérospatiale (CTA), Walter Julien ,   Centre Technologique en Aérospatiale (CTA), Arés Oliver ,   TD NDE, Brassard Michel
Published: July 2023

Ultrasonic inspection of large CFRP components requires an accurate positioning of the part with respect to the equipment’s coordinate system to ensure normal incidence during the scan. Fulfilling this condition often implies impractical and time-consuming manual adjustments of the part. A new method is proposed for ultrasonically determining the position of a complex part installed in an inspection system, and automatically correcting the offline-programmed path instead of iteratively and manually adjusting the part’s position. Two application strategies of our method are presented and experimentally tested on a complex CFRP landing gear component. The results suggest that even the simplest strategy using a planar learning scan of a randomly positioned part can produce C-scans of equal quality as those obtained with the manual alignment, in a fraction of the time that this process usually takes.
Adaptive ultrasonic rail wheel testing system with advanced phased array technology
Authors:   Waygate Technologies (former GE Inspection Technologies), Würschig Thomas ,   Waygate Technologies (former GE Inspection Technologies), Franzen Andreas ,   Waygate Technologies (former GE Inspection Technologies), Henrix Frank ,   Waygate Technologies (former GE Inspection Technologies), Chinta Prashanth Kumar ,   Waygate Technologies (former GE Inspection Technologies), Werner Daniel ,   Waygate Technologies (former GE Inspection Technologies), Kahmann Frank
Published: July 2023

Non-destructive wheel inspection by means of ultrasound testing (UT) is crucial for highspeed, local or cargo trains. Any failure can lead to catastrophic events resulting in high material damage and personal injury or even fatalities. However, the inspection of train wheels is complicated due to different defect positions, which are to some part difficult to access, and a large variety of wheel geometries which are, moreover, influenced by the milage of the wheels. This article describes an industrial solution for the full-body inspection of train wheels including face, flange, web and tread. To cope with the high complexity of the inspection task, the Krautkrämer WheelStar implements advanced UT technologies in combination with a high automatization level and user-friendly controlling and inspection tools. In the first part of this article, general probe configurations and the benefits of Phased Array Ultrasonic Testing (PAUT), in particular the use of matrix probes, will be discussed. Afterwards, setup and evaluation software of the testing machine will be presented. The final part contains selected measurement results highlighting the testing capabilities. Comparative studies reveal the improvements of matrix probes. Moreover, it will be shown in which way these give access to new features such as a high precision coupling check or geometry measurements allowing a compensation of wheel wear or the identification of the wheel type (“smart probe”).
High Temperature Magnetic Properties of Selected Steel Grades
Authors:   University of Manchester, Wilson John W. ,   University of Warwick, Zhou Lei ,   University of Warwick, Wu Fanfu ,   Tata Steel, Van Den Berg Frenk ,   Tata Steel, Yang Haibing ,   University of Warwick, Davis Claire ,   University of Manchester, Peyton Anthony J
Published: July 2023

In order to effectively control the microstructure of steel strip during manufacture it is vital that techniques be developed to monitor microstructural changes in the steel at high temperatures. Electromagnetic non-destructive testing is increasingly being used in these applications as it is non-contact, robust, relatively inexpensive and has the potential to provide real-time feedback to control the manufacturing process. However, if the data produced by these systems is to be fully exploited it is necessary to accurately measure the magnetic properties of steel grades of interest at temperatures up to the Curie point. This work details measurements carried out to assess the magnetic properties of selected steels grades, supplied by Tata Steel, up to the Curie temperature using a novel test rig based on a modified Epstein frame designed by the University of Manchester with high temperature trials at the University of Warwick. Several steel grades are studied with the full magnetic hysteresis (BH) loops reported during heating and cooling, along with extracted magnetic parameters including coercivity, magnetic saturation and magnetic permeability. The magnetic parameters of the selected steel grades are compared and implications of the results on electromagnetic monitoring of steel strip during manufacture considered. Results show the developed system has the potential to provide valuable data to inform online electromagnetic monitoring systems.
Evaluation of glycerol speed of sound
Authors:   University of Coimbra, Santos Jaime ,   University of Coimbra, Ferreira Abel G. M. ,   University of Coimbra, Ratkajec Anastazija ,   University of Coimbra, Santos Mario J.
Published: July 2023

The speed of sound in the liquid glycerol was calculated from the wave propagation time measurement in through transmission mode by using a designed acoustical cell. Measurements were carried out at atmospheric pressure and temperatures ranging from 298.47 K to 353.16 K. The proposed approach provided glycerol speed of sound values with experimental uncertainty of 1.9 m.s-1. The data were compared with the values from literature resulting in relative deviations around the range of 0.5%. The data were also used to develop an empirical equation for the calculation of the speed of sound covering the considered temperature range, with standard deviation  =2 m.s-1.
Passive guided wave tomography for monitoring corrosion in pipes
Authors:   Commissariat Energie Atomique (CEA), Druet Tom ,   University Paris-Saclay, Recoquillay Arnaud ,   Commissariat Energie Atomique (CEA), Chapuis Bastien
Published: July 2023

The use of guided waves enables to monitor wide areas of structures with a limited number of sensors and/or a limited acquisition time. In particular, guided wave tomography algorithms give a quantitative image of the residual thickness of the monitored structured, for example a corroded pipe. The idea is to use the dispersion curves to link a change in phase or group velocity to a change in thickness. The method developed at CEA-List includes an auto-calibration phase, eliminating the need of a baseline to work, therefore enabling its use in presence of varying environmental and operational conditions. One drawback of tomography techniques is that they need many sensors compared to more conventional algorithms such as RAPID or Delay and Sum. We propose here a passive version of tomography to limit its intrusiveness by using data obtained by post-processing the ambient elastic noise in the structure. This enables the use of Fiber Bragg Gratings (FBG) on optical fibers as ultrasonic sensors. The use of FBGs drastically reduces the burden of the system, as several gratings can be multiplexed on a single optical fiber. Furthermore, these sensors are suited for many applications because of their resistance to harsh conditions (extreme temperatures, explosive atmosphere, radiations…).
Applications of Linear Scanning Magnetostrictive Transducers (MST) for Finding Hard-to-Detect Anomalies in Structural Components
Authors:   Southwest Research Institute (SwRI), Vinogradov Sergey ,   Southwest Research Institute (SwRI), Chen Xin ,   Southwest Research Institute (SwRI), Cobb Adam ,   Southwest Research Institute (SwRI), Fisher Jay
Published: July 2023

Guided wave testing is now a widely accepted method for detection of structural damage in many different types of components, from pipelines to pressure vessels to tanks. Torsional wave modes (T modes) in pipes and shear horizontal (SH) mode guided waves in plates are good candidates for finding areas with generalized corrosion, due to the absence of fluid coupling effects and their lack of dispersion. However, from our field test experience, certain types of defects are difficult to detect with conventional T mode or SH mode guided wave probes. Gradual wall thinning is one such type of defect; another is crack-like defects in or close to welds or penetrations in the pipe. Recently, Southwest Research Institute (SwRI) has developed a new sensor configuration and scanning system that overcomes these limitations. We have recently developed a linear scanning magnetostrictive transducer (MsT) probe system, in which a FeCo strip wound with radio frequency (RF) coils is attached to the structure under test with shear wave couplant, and a moving permanent magnet driven by a motor is used to excite SH guided waves at predefined positions along this strip. The probe is designed to operate over a wide frequency range (20 – 500 kHz) and can be used to generate dispersive shear wave mode (SH1) in addition to the nondispersive SH0 mode. The use of different modes with the sensor at multiple positions allows detection of a range of defect types. In this paper, the performance of linear scanning MsTs is presented, including experimental evaluation of detection of gradual wall thinning patches of different depths and locations on a steel pipe and plate mockups. Another set of experiments evaluates detection of notches in seam welds. Indications from real-time B-scan and SAFT (synthetic aperture focusing technique) processing will be presented.
Detection and Measurement of Pitting Corrosion using Short Range Guided Wave Scanning
Authors:   Guided Ultrasonics Ltd., Horne Sam ,   Guided Ultrasonics Ltd., Leinov Eli ,   Guided Ultrasonics Ltd., Pialucha Tomasz
Published: July 2023

Short range guided wave scanning is an inspection method enabling an indirect, quantitative measurement of remaining pipe wall thickness. It has seen widespread industrial use as an inspection solution for corrosion under pipe support (e.g. [1]). Pitting corrosion represents a significant challenge in industrial pipelines and its presence complicates short range guided wave scanning analysis as the wavelength used for inspection is larger than the diameter of small pitting-type defects. This work investigates the reflected signal from pitting corrosion, both in isolation and in the presence of larger corrosion patches, to improve the understanding of the complex signals received. This work provides the foundation and guidance for analysis techniques used in guided wave scanning. To achieve this a series of representative pitting defects with varying diameter and depth have been investigated using explicit finite element modelling. It is shown that using currently established analysis techniques, the pit depth can be quantified for pitting with a diameter larger than approximately 13 mm. Smaller diameter pitting may only be qualitatively detected at this time due to mode conversion occurring at the defect, which obscure features that are used to provide quantitative analysis of the defect depth. Quantitative sizing of defects where pitting is present will require further investigation.
Quality Control Using Ultrasonic Phased Array Inspection of Components Produced by Directed Energy Deposition in Ti6Al4V Alloy
Authors:   ISQ Oeiras, Proença C. Sofia ,   ISQ Oeiras, Cabral A. M. ,   AIMEN Technology Center, Rodriguez P. Rey ,   AIMEN Technology Center, Vaamonde Eva
Published: July 2023

Additive manufacturing (AM) is rapidly becoming a viable manufacturing method for

industrial metallic parts. This is related to the benefits achieved, such as reducing material

wastage, an increase in design freedom and weight savings. But, to guarantee the highquality of the components produced, the non-destructive methods of inspection need to

be optimised or developed.

In this study, a Ti6Al4V 3D coupon was produced by the Laser Wire Directed Energy

Deposition process (w-DED-LB), in which artificial holes of different diameters

simulating defects were machined. To validate the quality control method after

production by means of Ultrasonic Phased Array Techniques, the component was

inspected using the Gekko equipment from Eddyfi Technologies, through the

methodologies of the phased-array conventional mode and the Total Focusing Method

(TFM). The probe used was a 5L64-64X7-NW1-P-5-OM, with a 5.0 MHz frequency

system with 64 elements, with dimensions of length 64 mm, width 7 mm, and pitch of 1.0

mm. The results obtained showed that the TFM mode provides better detection of the

defects, resolution, and measurement capabilities when compared with the conventional

phased array mode.
Automated honeycomb detection during Impact Echo inspections in concrete using AI trained by simulation data
Authors:   Helmut-Schmidt-University/ University of the Federal Armed Forces Hamburg, Dethof Florian ,   Helmut-Schmidt-University/ University of the Federal Armed Forces Hamburg, Kessler Sylvia
Published: July 2023

The Impact Echo method is well established in the civil engineering world of NDT for defect detection and thickness estimation in thick and highly reinforced concrete structures. For most applications of Impact Echo however, only the resonance frequency of the measured time signal is evaluated, meaning that most information is neglected. Here, artificial intelligence (AI) in the form of machine learning can help to classify signals based on multiple input parameters and therefore make use of the additional information stored in the measured signals. As the most powerful classification models need labelled input data, this usually marks a problem since labelled NDT data sets are rarely available for concrete structures. One solution to overcome this problem is the use of numerical simulations. In the past, numerical simulations showed that they are capable to produce realistic synthetic data for Impact Echo testing in concrete specimens. In this study, numerical simulations of Impact Echo measurements were conducted using the Elastodynamic Finite Integration technique (EFIT) to create training data for machine learning models. The measurements were carried out on two concrete specimens (17 cm and 50 cm thickness) containing honeycombs. Using the simulation data, multi-layer perceptron (MLPNN) and convolutional neural networks (CNN) are trained and tested on measured data from each specimen for performance. Results showed that an accurate honeycomb detection using machine learning was only possible in some cases with many false alarms arising near the specimen edges.