bluuebunny/crossref_metadata_2025 huggingface dataset:
3D Hybrid modeling for the ultrasonic phased array inspection of porosity in heavy plates: Simulation and experimental validation
Authors:   Rosenxt Creation Center GmbH, Kolkoori Sanjeevareddy ,   Rosenxt Creation Center GmbH, Koch Roman ,   Rosenxt Creation Center GmbH, Falter Stephan
Published: May 2024

Quantitative NDT modeling and simulation tools are important in design and fabrication of ultrasonic phased array
probes with optimum characteristics and reduce the number of experimental efforts and development time. In order
to achieve high accuracy (Amplitude deviation < 1 dB) with a low computational time in the simulation, the
modeling tools require not only the high-frequency approximation of the ultrasonic wave propagation but also the
high-precision electro-acoustic coupling model.
This paper describes a computationally efficient 3D time-dependent hybrid model for the simulation
of ultrasonic phased array inspection of porosity in heavy plates. This method combines the results of both 3D
finite element analysis (PZFLex-FEA) and the semi-analytical ultrasonic simulation “Ray-Tracing”.
As a first step, we demonstrate the FEA modeling of an ultrasonic phased array probe, which includes
the full 1-3 piezocomposite design with the arrangement of array elements, conducting electrodes, multi-phase
backing material, acoustical matching layer and electrical circuit of a 50 Ohm coaxial cable. In the current FEA
simulation, we considered the acoustical and electrical cross-talk between the adjacent elements of an ultrasonic
array sensor.
In the second step, the FEA-simulated ultrasonic pulse-echo signal and its frequency spectrum of an
array element in the farfield region are further used as the reference input signal in the CIVA-UT software to
simulate the imaging of porosity in heavy plates, quantitatively. The design of the 3D wedge-geometry of the
application specific array sensor is modeled and optimized using the CIVA raytracing and multi-phase backing
models. The real excitation pulse of the industrial ultrasonic testing equipment “ROMIS (ROSEN Modular
Inspection System)” is also included in the simulation to achieve high accuracy in the current hybrid modeling.
The dependency of the detectability of the porosity on the frequency of the array sensor and the active element
group so-called “Virtual Probe” are quantitatively analyzed.
Finally, the 3D hybrid model simulated Time Corrected Gain (TCG) curves of the porosity like defects
in the reference steel plates are compared with the real experiments and a good quantitative agreement is achieved.
Magnetic and acoustic sensors in the age of digitalization for industrial production
Authors:   QASS GmbH, Barteldes Sören ,   Bochum University of Applied Sciences (BO), Müller Eckehard ,   QASS GmbH, Radek Christian
Published: May 2024

The challenges of digitalization are giving rise to new generations of measurement technology.
This does not necessarily involve the use of new physical principles; rather, the importance of
handling and generating valuable data has increased. We present a new measuring system that
samples and digitizes analogue signals at 50 MHz with 24-bit conversion. Every 43 µs, a
Fourier step is generated for 1,024 data points via an FPGA-based measurement card. The
resulting spectral data diagram can then be electronically filtered to improve the signal-to-noise
ratio. With this procedure, further possibilities have been created to improve data analysis and
data handling, one of which is a parametric pattern recognition, which transfers selectable
signals to a library based on the spectral data diagram and searches for them in future data using
a similarity algorithm. The use of Python is another building block. With Python, machine
learning methods can be transferred from training directly to the measurement system and can
run there directly using the extensive library standards. Sensor-fusion is a module that allows
analog data to be analyzed via the measurement card, but at the same time also links digital data
with analog data by connecting DAQ modules from a third source as virtual ports and
transmitting values to shared databases. This article shows the application of the described
measurement concept using magneto-inductive sensors and piezoelectric sensors.
Magnetic sensors react sensitively to material changes and can reliably determine mechanical
parameters such as hardness, residual stresses and grain size. The mentioned software functions
enable non-contact measurement of ferromagnetic materials at high throughput speeds. So far
limited to laboratory applications, magnetic sensors can also be used safely in harsh industrial
conditions. Applications include rapid differentiation of heat treatment conditions, detection of
grinding burn and hardness measurements.
Acoustic sensors are used in areas that are difficult to access or whose environmental conditions
make the use of optical systems in particular difficult. The sensors can mainly detect cracks,
frictional behaviour and wear quantities. Applications are in particular straightening processes
of hardened steel components, wire drawing, welding, deep drawing and machining.
In general, this method can also be used to monitor other sensors and thus raise them to a new
level of evaluation technology and data analysis.
To Evaluate the Degradation of Heat Damaged Concrete Specimens after Curing Using Non-Linear Ultrasound Technique
Authors:   National Atomic Research Institute, Pei Kuang-Chih ,   Chaoyang University of Technology, Kan Yu-Cheng ,   National Atomic Research Institute, Lin Yu-Ju ,   National Atomic Research Institute, Lee Jian-Jhou
Published: May 2024

In this research, Non-linear Ultrasound (NLU) technique was used to evaluate the degradation on heat damaged
cement mortar specimen behaving explicit nonlinear. Mortars of Portland cement type I (or normal cement, NC)
were chosen to mold the specimens with water cement ratios of 0.4, 0.5 and 0.6, and size of 5x5x5cm-cube and
5x5x2cm-brick. The specimens were grouped for heating at different temperatures (30, 200, 300, 400, 600, 800℃
for 24 hours) to create degradations of different levels. After curing process in water for 28 days, mechanical
property tests were carried out on each cube to get its stress-strain relation and strength. NLU tests were conducted
on the brick specimens. The RITEC SNAP System with 250kHz/transmit and 500kHz/receive transducers was
used to conduct the measurement of harmonics. The obtained amplitudes in spectrum of fundamental, 2nd and 3rd
harmonics (A1, A2 and A3) and the amplitudes due to the background nonlinearity by facility (A01, A02 and A03)
were analyzed to approach the nonlinear parameters for each specimen, such as the β and γ. The [(A01-
A1),(A03/A 3 2

01 -A3/A13)] and[(A01-A1), |A02/A01 -A2/A12|] were applied as a nonlinear characteristic index to mark
the quality of the microstructure of material, which could be related to the durability and workability of the material.
The results showed a promised quantification method using NLU. Extended application can be expected.
To Monitor Fracture Behaviors in Four-Point Cyclic Bending Tests of Low-Activated High Alumina Concrete and Standard Concrete RC Beams Using Acoustic Emission Technique
Authors:   National Atomic Research Institute, Pei Kuang-Chih ,   Chaoyang University of Technology, Kan Yu-Cheng ,   National Atomic Research Institute, Lee Jian-Jhou
Published: May 2024

In this study, acoustic emission monitory (AE) was used to observe and evaluate the mechanical behavior of two
kinds of RC beam members, made of low-activation concrete and normal concrete, by general four-point bending
test and cyclic four-point bending test. During the loading, acoustic emissions due to cracking, shearing, rubbing,
de-bonding or interlocking could be monitored and recorded using a real-time high sampling rate DAQ system
and proper sensors; besides, beam displacement, cracking situation and loading were also measured
simultaneously. The experiment goals included: (1) to observe the damage mechanisms of the beams under
bending test and their corresponding AE performance; and (2) to observe the material fracture and corresponding
AE in the beams under the cyclic bending test of 0.5Hz (periodic dynamic condition). After experiments, the
fracture history of the beam under general loading test could be revealed through the comparison for the chronicled
AE signal density and load/strain data. The damage on beam under the cyclic test could be analysed through the
chronological comparison for the cumulative sum of AE signal counts obtained for different test periods and stages.
Both the irreversibility on fracture mechanism (affected by the Kaiser effect) and the “remainder toughness” could
be discussed through the quantitative analysis on AE characteristics for two different beams. They might relate to
the durability and toughness of material for beam.
Scan Time Reduction by Fewer Projections - an Approach for Circular and Spherical Trajectories
Authors:   Siemens Corporate Technology, Bauer Fabian ,   Siemens Corporate Technology, Goldammer Matthias ,   Technical University of Munich (TUM), Grosse Christian U.
Published: May 2024

For most computed tomography scans a circular or helical trajectory is used to acquire the necessary radiographic
projections. However, these standard trajectories are not necessarily the best choice since the shape of the inspected
object is not considered which leads to a suboptimal sampling of the part. In contrast, workpiece-specific and more
efficient scan strategies hold the potential for time and cost savings. Such adaptions might be of particular interest
for future robotic CT systems that allow greater flexibility in the positioning of X-ray tube, object, and detector
than conventional setups or multi-source applications with predefined positions by the setup. We propose a scan
planning algorithm to adapt the acquisition trajectory considering the shape of the investigated part. For this task,
we present an algorithm that is able to identify the projections from a set of projections that contribute most to the
reconstruction of the object. As input information, only the localization of the area of interest and projections from
the feasible range of motion are necessary. Also, a reasonable amount of projections to pick from needs to be
provided, which can originate from an earlier scan or computer simulations that consider the range of motion of
the available CT setup. The optimization method has been implemented for circular and spherical trajectories and
can be extended towards arbitrary acquisition paths. Since for modern CT systems the duration for the scan itself
takes significantly longer than the reconstruction, this approach appears to be well-suited to significantly reduce
the throughput time if several identical parts need to be inspected. Additionally, new applications such as inline
CT are conceivable and certain artifacts can be suppressed if spherical trajectories are used instead of circular ones.
For the subsequent reconstruction itself no previous knowledge of the object is included, i.e. the reconstruction
workflow does not need to be modified. We demonstrate the capabilities of the optimization method for two
industrial relevant examples and show that a scan time reduction of more than 50 % is feasible for some cases by
reducing the number of acquired projections. Furthermore, for all investigated projection numbers and parts the
optimized trajectory yields an identical to clearly improved image quality in the reconstructed volume than the
reference trajectories.
Laser generated Ultrasound System (LUS) and its application for the Non-Destructive Testing of metallic components
Authors:   San Sebastián de los Reyes, Sillero Amador ,   San Sebastián de los Reyes, Fernández Francisco J.
Published: May 2024

One of the investigation areas regarding the Ultrasonic Non-Destructive Test (UT-NDT) is the development of
non-contact technologies like Air-Coupled UT, EMAT or UT generated by Laser. These technologies show several
interesting advantages like no couplant needed or their application to the inspection of components with complex
geometries and extreme surface conditions (temperature, roughness, radiation…).
In the Laser Ultrasonics Techniques (LUS), ultrasound is generated by a pulsed laser that produces a thermal
expansion of the surface where it impacts and generates vibrations at ultrasonic frequencies. These vibrations can
travel through the inside of the material and its surface; and they are reflected, refracted or diffracted in the defects
or discontinuities of the material. The disturbances generated by the interaction of the vibration with the defects
are detected in another point of the material using a secondary detection system.
Tecnatom is working with LUS technology since 2010, acquiring, installing and optimizing a laboratory system
for its implementation in the inspection of metallic materials (aluminum, carbon steel and stainless steel). During
this time, several works have been carried out to determine the scope of the technology as: initial study for the
characterization of the waves generated by the laser; studies in test blocks without discontinuities to determine the
experimental conditions in which ultrasonic disturbances are generated in thermo-elastic and ablative regime;
simulations and microstructural studies of the pieces to determine both the structural state and the residual stresses
caused by the incidence of the laser; inspection of blocks with artificial reflectors, both superficial and embedded,
and set-up techniques to increase the amplitude of the detected signal; optimization of the detection system through
the combination of technologies and identification of safety criteria, use and improvement of the system for
validation use in industrial environments.
In this work, Tecnatom presents the main conclusions of the development carried out to determine the capacities
and limitations of the techniques based on Laser Ultrasonics for its application in Non-Destructive Testing for the
inspection of metallic components.
Principle of the electromagnetic testing based on the varied frequency domain and its realization
Authors:   Huazhong University of Science and Technology, Wu Xinjun ,   China Special Equipment Inspection and Research Institute (CSEI), Hu Bin ,   China Special Equipment Inspection and Research Institute (CSEI), Shen Gongtian ,   Wuhan University of Science and Technology, Ding Xu ,   Huazhong University of Science and Technology, Wang Junjie
Published: May 2024

With the development of modern industry, the types and quantities of industrial equipment are increasing. In the
long-term production process, various failure modes such as corrosion and cracks will occur, therefore the
workload of inspection will increase dramatically. It is extremely urgent to study the combined non-destructive
testing (NDT) technology and develop corresponding multi-functional instruments to achieve rapid inspection. In
this paper, an electromagnetic testing principle based on the varied frequency domain is proposed. In the first place,
spatial uniformity and spatial periodic static fields are generated by the arrangement of the permanent magnetizers,
these static fields are fields with different spatial frequencies. In the second place, dynamic fields with different
frequencies are generated by different frequencies excitations. Under the time-space electromagnetic field
coupling, a new combined electromagnetic testing principle of magnetic flux leakage (MFL), guided wave (GW)
and electromagnetic acoustic transducer (EMAT) is proposed. The MFL testing method can be realized based on
the uniform static field, GW based on the interaction of spatial periodic static field and low frequency dynamic
field, while EMAT based on the combination of uniform static field and high frequency dynamic field. According
to the above principle, a multi-functional instrument is developed, which includes a medium-low frequency
excitation unit for GW, a high frequency excitation unit for EMAT, corresponding receiving amplifiers for
GW/EMAT/MFL, and USB-based data transmitters. Finally, the relevant performance tests are carried out, which
laid the foundation for field application.
Chirp-coded ultrasound for localization of linear and nonlinear scatterers in isotropic media
Authors:   Tallinn University of Technology, Lints Martin ,   Tallinn University of Technology, Salupere Andrus ,   INSA Centre Val de Loire, Blois campus, University of Tours, Dos Santos Serge
Published: May 2024

Chirp-coded ultrasound has been under active research for reciprocal Time Reversal with
Nonlinear Elastic Wave Spectroscopy for ultrasonic wave focusing and additionally detection
and analysis of nonlinear defects. Localization and imaging of defects under these principles,
without scanning or use of other complicated methods, is an open problem. Frequency
Modulated Constant Wave technology is widely known in radar applications where the distance
to multiple reflecting targets, their velocities and angles of return are found from the chirp signal.
These principles are not yet widely used in ultrasound technology. Chirp-coded ultrasound is
common between the two methods and enable to maximize total power on target due to longer
transmitted signals (as opposed to pulsed operation). This work proposes to unite the
Frequency-Modulated Constant-Wave scatterer localization with reciprocal Time Reversal –
Nonlinear Elastic Wave Spectroscopy principles to enable the localization of scatterers distant
from the transducers and the analysis of their nonclassical nonlinearity which often can be
caused by microdamage or cracking. In this paper only the first part (localization of scatterers
using frequency-modulated constant wave ultrasound) of the problem is investigated. The main
goal is to verify the feasibility of the method for ultrasound in solids and identify the main
problems to be solved. Physical experiments and simulations are used to ascertain the
detectability of linear and nonlinear scatterers in an isotropic solid medium (acrylic) using
ultrasound. Potential problems with this approach are identified, to be solved in future work. In
the future, this approach could enable to spatially filter the return signals, enabling to use
reciprocal time reversal for focusing the wave energy in space directly onto selected scatterers,
using the simplest of test setups: one transmitting and two receiving transducers.
Research on intelligent classification of weld defects based on improved ResNeXt network
Authors:   Inner Mongolia University of Science and Technology, Wang Shaofeng ,   Inner Mongolia University of Science and Technology, Chen Tengyu ,   Inner Mongolia University of Science and Technology, Zhang Rong ,   Inner Mongolia University of Science and Technology, Liu Wengjing ,   Inner Mongolia University of Science and Technology, Lv Da ,   Inner Mongolia University of Science and Technology, Zhang Yaowen
Published: May 2024

Welding technology is widely used in the connection of metal workpieces, and then due to improper operation
and other reasons, small defects may occur in the welding, which will lead to welding failure and hazardous
accidents. Therefore, it is very important to accurately identify welding defects. The automatic defect
identification method based on deep learning learns features directly from the full-focus mapping of weld defects
and automatically classifies them; the ResNeXt network is selected for improvement, and the SK convolution unit
is introduced into the original ResNeXt-50 network model to enhance the adaptive adjustment of sensory field; in
order to alleviate the problem of the point-by-point convolution in the ResNeXt-50 which consumes a large
amount of In order to alleviate the problem that point-by-point convolution in ResNeXt-50 consumes a large
amount of computation, 1×1 group convolution is used instead of the original point-by-point convolution, and
channel rearrangement is introduced to alleviate the problem of weakened information exchange of groups caused
by group convolution. After improvement, the ResNeXt-50 network model can achieve a classification accuracy
of 98.2%, which is 5.5% more than that of the original ResNeXt-50 on this paper's dataset, and the classification
accuracy after T-sne visualization also has obvious separation boundary and clustering effects.
Non-contact Testing of Large Concrete Structures for Voids and Delaminations
Authors:   Fraunhofer-Institut für Großstrukturen in der Produktionstechnik IGP,, Heinze Christoph ,   Fraunhofer-Institut für Großstrukturen in der Produktionstechnik IGP,, Weiher Karsten ,   Fraunhofer-Institut für Physikalische Messtechnik IPM, Vierhub-Lorenz Valentin ,   Fraunhofer-Institut für Physikalische Messtechnik IPM, Werner Christoph ,   Fraunhofer-Institut für Großstrukturen in der Produktionstechnik IGP,, Geist Michael
Published: May 2024

Concrete is the most used construction material for civil engineering structures, as it is reliable, cost-efficient, and
long lasting. Infrastructure made of reinforced concrete can be used for many decades, provided that maintenance
is rigorous. The necessary periodic checks are typically manual tasks, including visual inspection for defects on
the outside and hammering to find internal voids and imminent spalling.
In this a paper, a non-contact system for automated inspection is presented. Two parallel lasers are used with a
scanning head on a mobile platform to cover large areas. The first laser emits a high energy pulse, igniting plasma
on the surface and subsequently inducing a shock wave into the structure. The second laser measures the resulting
vibration. Signal analysis of individual measurement points give a first indication about the presence of faults.
Unsupervised learning and visual computing are used to find and narrow down damaged areas in the scanning data
with higher probability. After systematic testing in the laboratory, measurements were conducted recently in two
tunnels with concrete linings. This paper provides an overview of the developed hardware and signal analysis
techniques. Furthermore, the recent verification results are presented for the first time.
In future, the proposed method can be combined with geometric scans and automated optical inspection of the
surface to offer a holistic inspection approach and relieve the authorities that are responsible for operation and
maintenance of the growing number of aging infrastructures.
Weld Defect Downscaling Recognition for Phased Array Ultrasonic Data Based on Semantic Segmentation
Authors:   Shanghai Jiao Tong University, Zhang Sen ,   Shanghai Jiao Tong University, Zhang YanSong
Published: May 2024

Phased array ultrasonic testing (PAUT) is one of the most advanced ultrasonic inspection methods, providing
inspection data in image sequences with increased resolution and coverage, consequently enhancing inspection
efficiency. Due to the inherently abstract nature of ultrasound images, the analysis of PAUT weld data continues
to rely on the expertise of experienced inspectors, particularly in the context of shipbuilding welds, which exhibit
characteristics such as arbitrary lengths, varying thicknesses, and various weld methods, particularly when
associated with hybrid laser-arc welding involving higher caps and narrower fill widths. This paper applies a
semantic segmentation architecture to PAUT data for hybrid laser-arc welding to segment defects automatically.
A downscaling PAUT image dataset incorporating PAUT imaging principles with scan processes is established.
The proposed architecture adopts an encoder-decoder architecture and segments defects downscaling, enabling
direct localization and sizing defects in long PAUT data. Meanwhile, it handles PAUT image sequences of
arbitrary length, eliminating the need for horizontal scale normalization while preserving the integrity of defect
shapes. The proposed architecture was validated in the dataset to demonstrate the superiority of the proposed
method in locating and sizing defects in PAUT weld data, offering a promising automated solution to a challenge
in ultrasonic inspection methodologies.
Vibration analysis of a partially submerged structure using the DIC technique
Authors:   Chaoyang University of Technology, Lin Yung-Chiang ,   Chaoyang University of Technology, Jiang Meng-Ting ,   Chaoyang University of Technology, Chiang Chih-Hung
Published: May 2024

The continuous expansion of offshore wind turbine sites has been garnering increasing attention, particularly in
countries where available land is limited. Nevertheless, efficiently allocating resources for the maintenance and
repair of offshore wind turbines presents a formidable challenge. This challenge is compounded by the complex
and often unpredictable weather conditions, as well as various business-related issues specific to the offshore
environment. To tackle these challenges, one effective solution is to implement vibration analysis through the use
of digital image correlation (DIC) methods. This approach has a well-established theoretic background dating back
to approximately 2008 and has demonstrated its effectiveness in the realm of structural health monitoring for large
structures like bridges and towers. Relevant information on the upper structure of the wind turbines has been
obtained using numerical models in our previous work. Changes in the structural feature frequencies of wind
turbines are the primary focus in vibration analysis. However, changes in feature frequencies can occur for various
reasons, and relying solely on frequency shifts can make it challenging to pinpoint the precise areas of damage
within wind turbine structures, especially without the benefit of long-term observations. In this study, the DIC
method is employed on scaled cylindrical models to gain insights into the frequency variations stemming from the
erosion of non-cohesive soils beneath offshore wind turbine foundations. Changes in modal curvature within the
upper structure of the wind turbine will also be analyzed. This additional investigation will enable a clear
differentiation between defects in the upper structure and frequency shifts resulting from erosion or problems with
the underwater foundation.
Characterization of Rigid and Flexible Digital Detector Arrays Using ASTM E2597/E2597M-22
Authors:   Carestream NDT, Carpenter Katie M.
Published: May 2024

ASTM E2597/E2597M-22 is a standard that summarizes a standard practice for characterization of digital detector
arrays (DDAs) by manufacturers. The standard consists of a series of tests intended to deliver quantitative results
for a given model of detector’s characteristics as they should perform upon sale. It was written for use in
characterizing rigid detectors, but the tests are applicable to bendable DDAs, utilized for single viewing. Bendable
DDAs, unlike their rigid counterparts, are made to conform around parts being inspected, such as pipes, in a similar
application to film and computed radiography for imaging curved objects. As bendable DDAs are made using the
same scintillators as flat panel DDAs and have similar pixel pitch and resolution capabilities, it is expected that
the results from most characterization tests should be similar. Conformable DDAs produce similar imaging results
as rigid DDAs but have the flexibility of use for curved surfaces. They offer a valuable tool for customers currently
using film and CR who are looking to expedite their inspections or move away from use of consumable products.
We performed these characterization procedures on conformable DDA models and rigid DDA models utilizing
proprietary INDUSTREX software developed by Carestream Health, Inc. The experimental results are presented
as part of this paper.
Real-Time Phased Array Ultrasonic Monitoring of Debonding Growth Under Cycling Loading in CFRP
Authors:   VTT Technical Research Centre of Finland, Inc Yasemin ,   VTT Technical Research Centre of Finland, Kuutti Juha ,   VTT Technical Research Centre of Finland, Raunio Kalle ,   VTT Technical Research Centre of Finland, Viitanen Tomi
Published: May 2024

Carbon Fibre Reinforced Polymer (CFRP) composites are widely employed in diverse industries due to their
specific stiffness and strength, and corrosion resistance. However, over time, service-induced damage can initiate
a failure that can threaten the operation’s safety and reliability, especially in critical industries like aerospace
applications. The challenge lies in identifying and monitoring the defects before they escalate into serious issues.
Non-Destructive Testing (NDT) methods play a pivotal role in this scenario, aiming to detect and evaluate defects
without causing harm to the material. Detecting flaws in composite materials such as CFRP remains a complex
task. Traditional NDT methods often struggle to effectively pinpoint and assess defects within these intricate
structures. However, recent advancements in ultrasonic testing, especially Phased Array Ultrasonic Testing
(PAUT), show promise in examining the internal composition of CFRP composites with higher accuracy and
reliability.
This study aims to demonstrate the applicability of PAUT for real-time monitoring of debond growth under
dynamic loading. The loading was applied to the test specimens up to one million cycles, and 64 elements 2 MHz
linear phased array probe was attached to the specimen. The acquired signals were analyzed and could also be
recorded for offline processing or archiving.
To validate the credibility of the findings, the performance of PAUT was compared to Acoustic Emission (AE), a
well-established method for detecting and analysing high-frequency signals emitted by materials undergoing
deformation or damage. Encouragingly, both methods exhibited similar trends in capturing the growth of debond.
Furthermore, to verify the final defect lengths, post-test ultrasonic C-Scans utilizing the through transmission
technique were conducted, complemented by visual inspections. These assessments served to confirm the accuracy
and reliability of the results obtained through Phased Array Ultrasonic Testing.
Real-time monitoring of composite structures using phased array technology comprises a valuable tool for real-
time assessment of debonding in the composite. As industries continue to rely on Carbon Fibre Reinforced Polymer
composites for multifaceted applications, the utilization of advanced Non-Destructive Testing methodologies like
Phased Array Ultrasonic Testing emerges as a cornerstone in guaranteeing their continued integrity and
performance.
Development of multi-channel magnetic flux leakage testing system for bridge cables
Authors:   Huazhong University of Science and Technology, Sun Lingsi ,   Huazhong University of Science and Technology, Tao Zhiwei ,   Huazhong University of Science and Technology, Ouyang Quan ,   Huazhong University of Science and Technology, Wu Xinjun
Published: May 2024

Magnetic flux leakage (MFL) is one of the most popular techniques for detecting broken wire in bridge cables.
MFL sensor array has attracted a lot of attention in recent years due to its capacity to measure the spatial
distribution of the magnetic field of bridge cable. More sensors in the array lead to increased useful information
extraction from the MFL field, allowing for more precise quantitative evaluation of bridge cable damage. This
study reports the development of a cable MFL testing system capable of synchronous acquiring up to 512 channels
of MFL sensors signal. Radial sensor arrays (RSA) composed of vertically placed magnetic sensors spaced at equal
intervals are developed to be arranged around the bridge cable. They record the spatial distribution of the magnetic
leakage field of the broken wire by collecting the MFL signal at various lift-offs. To solve the problem of multi-
channel MFL signal synchronous acquisition, this study develops a MFL signal acquisition card based on
multiplexing technology, capable of synchronous acquisition of up to 512 channels of MFL signal. Multiplexers
are used to switch sensor channels, followed by multi-channel A/D conversion chips to convert the transmitted
data. The converted data are temporally stored in the First-In-First-Out (FIFO) buffer of the Field Programmable
Gate Array (FPGA) and transferred to the computer through the network port for display, storage, and signal
processing. Finally, the motion control circuit, mechanical structure, and control software of the bridge cable MFL
testing system are fully customized. Experiment results reveal that the system can be used in multi-channel MFL
testing, laying the foundation for further multi-channel signal processing and bridge cable health evaluation.
Grouting inspection of PC bridge girder using Ultrasonic Pulse Echo Tomography and multiparameter evaluation procedure
Authors:   CORE Institute of Technology Corp., Sagradyan Artur ,   Kyoto University, Ogura Norihiko ,   Kyoto University, Shiotani Tomoki
Published: May 2024

Assessing the condition of grouting in post-tensioned tendons within Prestressed Concrete (PC) structures stands
as a challenge in the field of civil engineering infrastructure maintenance. Current non-destructive testing (NDT)
techniques employed for grouting assessment have certain constraints. For instance, the Impact-Echo method
exhibits relatively low accuracy, while the X-Ray method proves to be costly and demands significant time and
labor resources. Simultaneously, there exist promising alternative NDT techniques that offer potential for grouting
inspection. In this study the authors used commercially available Ultrasonic Pulse Echo Tomography device with
an array of dry-contact sensors and multiparameter method of evaluation. The evaluation method uses amplitude
of ultrasonic pulse reflected from PC sheath, backwall and phase of reflected ultrasonic pulse. The experimental
study on large-scale specimens confirmed that the evaluation method allows to achieve higher accuracy, as
compared to existing methods of evaluation. The developed procedure was applied for inspection of PC bridge
girder on an existing road bridge. The inspection was carried out on one of the spans of the bridge, which had 4 I-
shaped PC girders. The results of Ultrasonic Pulse Echo Tomography were confirmed by means of drilling and
borescope inspection method The results of both methods showed good correlation.
A low-power AE b-value sensor for structural health monitoring
Authors:   Toshiba Corporation, Ueda Yuki ,   Toshiba Corporation, Usui Takashi ,   Toshiba Corporation, Watabe Kazuo
Published: May 2024

An increase in the quantity of aging infrastructure has become a major social issue. It is thus necessary to properly
maintain and manage aging infrastructure, which incurs increasingly large maintenance costs. Therefore, there is
a demand for maintenance and management using low-cost and wide-application technologies such as Internet of
Things (IoT). We propose a unique, ultra-low-power acoustic emission b-value sensor for structural health
monitoring. Acoustic emission (AE) is an elastic wave generated by crack generation or growth inside a material.
The characteristics of AE, such as waveform, source frequency, source location, and velocity, can indicate damage
affecting material strength. When focusing on the source frequency, the b-value, which is the slope of AE
amplitude-frequency distribution derived from the source frequency, is important and widely used as an indicator
of material integrity. The proposed sensor was developed to detect this b-value trend more conveniently than ever
and to achieve continuous structural or machinery health monitoring. We pursued two key points: ultra-low power
consumption and long-distance wireless transmission, which enabled the AE sensor to be applied as an IoT sensor.
The wake-on-AE algorithm, which wakes the sensor when AE waves reach the sensor, enables AE sensing to
consume a very low current of 172μA on two dry batteries. Generally, the waveform of AE is very short in duration,
such as microseconds to milliseconds. If the sensor did not wake up and take measurements in such a short time,
the AE wave would pass, and the sensor would fail to measure AE. Therefore, we developed a unique analog-
digital co-circuit technology that uses a peak-hold circuit to extract AE features with less sampling. In addition,
sensor edges reduce data rates through statistical analysis and transmit data using low-power wide-area networks.
In this paper, we present validation results obtained with the sensor on bearings. We performed validation
experiments with faulty and normal bearings, generating AEs with different b-values. The developed sensor,
operated with two dry batteries, and the AE measurement systems for verification simultaneously acquired the AE
generated by the bearing rotation. As a result, we successfully confirmed that the developed sensor provides almost
the same results as conventional AE systems in b-value measurement with ultra-low power consumption.
Viscoelastic characterization of coating layers by ultrasonic interference and critical attenuation
Authors:   Osaka University, Mori Naoki ,   Osaka University, Hayashi Takahiro ,   Osaka University, Okabe Taiki
Published: May 2024

This study proposes a characterization technique for a viscoelastic coating layer on a metal substrate immersed in
water based on ultrasonic interference and critical attenuation phenomena. Theoretical analysis shows that the
reflection spectrum for the normal incidence wave has local minima at the resonance frequencies of the coating
layer, which provide its elastic property if the layer thickness is given a priori. Furthermore, it is revealed that the
lower envelope of the reflection spectrum takes a minimum, whose frequency can be related to the critical
attenuation condition. This feature implies a possibility that the viscous property of the coating material can be
estimated by similarly measuring a characteristic frequency to the estimation of the elastic property. Two bonded
specimens consisting of polycarbonate (PC) sheets and metal substrates were prepared to validate the proposed
method. The reflection spectra measured for the normal wave incidence showed multiple local minima and critical
attenuation, which are predicted to appear by theoretical predictions. The wave velocities and loss factors of PC
estimated from the two specimens are in fair agreement with the properties shown in the previous paper. This
result demonstrates that the ultrasonic interference and critical attenuation behavior can be applied to the
characterization of the viscoelastic coating layers.
Development of an energy-autonomous eddy current sensor system for in-situ component monitoring
Authors:   Leibniz University Hannover, Gansel René ,   Leibniz University Hannover, Zwoch Stefan ,   Clausthal University of Technology, Quanz Markus ,   Clausthal University of Technology, Schäfer G. ,   Clausthal University of Technology, Lohrengel Armin ,   Leibniz University Hannover, Maier Hans Jürgen ,   Leibniz University Hannover, Barton Sebastian
Published: May 2024

Energy-autonomous non-destructive testing (NDT) systems provide new opportunities for structural health
monitoring. An NDT system that is energy-autonomous and transmits the recorded data wirelessly can be used in
places that are not easily accessible for inspection. In addition, it can provide for continuous monitoring, which
can improve the operational safety of various components and structures.
This study presents a concept that enables energy-autonomous and wireless structural health monitoring using a
splined shaft as a demonstrator. To monitor mechanical overloads, a material sensor is applied to critical areas of
these components by a laser heat treatment. The structural change that occurs as a result of an overload can be
monitored by the developed smart sensor system. This system consists of a material sensor, a low-cost eddy current
sensor, an energy-efficient evaluation unit with an ultra-low-power microcontroller unit (MCU) and a Long-Range
Wide Area Network (LoRaWAN) data transmission unit. Wireless data transmission via LoRaWAN provides
access to the Industrial Internet of Things network, enabling the collection of NDT data from multiple smart
sensors in a cloud and the processing of these data to assess the condition of the component from any location. It
is shown that the MCU-based eddy current testing system is able to generate a similar signal quality for material
characterisation compared to an industrial eddy current testing system, despite a much more compact design and
a significantly higher energy efficiency. The energy autonomy of the smart sensor system is achieved by an energy
harvesting system integrated into the splined shaft. In addition, three different testing scenarios are presented,
which differ mainly in the scope of data processing and evaluation on the MCU, and thus also in the energy
required.
Two-scale finite element simulations for UT inspection of micro-structured materials in CIVA
Authors:   University Paris-Saclay, Demaldent Edouard ,   University Paris-Saclay, Leymarie Nicolas ,   University Paris-Saclay, Dorval Vincent ,   University Paris-Saclay, Imperiale Alexandre ,   University Paris-Saclay, Fortuna Thibaud
Published: May 2024

Ultrasonic testing (UT) of highly heterogeneous structures is an important issue for many industrial applications
in civil engineering for concrete inspection as well as in nuclear and oil & gas, where it applies to cast steels and
weld joints. In these materials, performance is limited by the phenomenon of multiple wave scattering at the
microstructure scale. In this context, the use of effective simulation tools is particularly useful both for improving
interpretation of UT and for optimizing or demonstrating the performance of inspections. However, the scales of
heterogeneity to be taken into account are often smaller than fractions of a tenth of a wavelength. In 3D simulations,
it is therefore difficult, if not impossible, to combine computational performances with the refinement of the
modelled interactions. To meet this challenge, CEA is developing an original approach based on two applications
of the finite element (FE) method implemented in CIVA. The first application uses micro-scale heterogeneous
material data on small representative elemental volumes (REVs) to feed a second code dedicated to macro-scale
with effective medium characteristic. This second code relies on a high-order finite element model that is very
efficient at the scale of the inspected industrial component. In this communication we present the main features of
these FE tools and illustrate their performances on different application cases for welded parts and concrete
Investigation of the shape-changing property of X-ray computed tomography in the evaluation of pores
Authors:   University of Erlangen-Nürnberg (FAU), Baumgärtner Benjamin ,   University of Erlangen-Nürnberg (FAU), Sienz Vera ,   University of Erlangen-Nürnberg (FAU), Hausotte Tino
Published: May 2024

Porosity in additive manufacturing is one of the main quality characteristics for components. In processes such as
laser-based powder bed fusion of metals (LPBF-M), correlations can be observed between the process parameters
used, such as laser power, hatch distance or layer thickness, and the pore shape produced. Therefor the surface
depending criterion sphericity is a crucial parameter for the classification of pores. In addition to methods like
micrographs or Archimedes' density determination, industrial X-ray computed tomography (CT) is a key
measurement method for the spatial but also shape-dependent assessment of pores in components. However, due
to the lack of standards, no measurement uncertainty for shape, position, and volume can be given for CT
measurements. With the help of CT simulations and models for detector and X-ray source to real CT system,
investigations can be made on the dependencies and influence on the detectability of pores. This study shows that
the CT measurements as well as the analysis have an influence on the detectable volume and surface of pores. By
modelling pore models with cosine periodic spatial frequencies (peaks), the spatial influence of CT on detectability
can be investigated and assessed as a form of slope distribution. The simulation-based measurement uncertainty
information can be used to improve the separation of pore shape classifications and thus contribute to the
development of additive manufacturing.
Improving defect detection capability of pulse and pulse phase thermography method for CFRP plates by enhancing rear surface heat transfer coefficient
Authors:   University of Tokushima, Sengoku Shuhei ,   University of Tokushima, Ishikawa Masashi ,   University of Tokushima, Nishino Hideo ,   IHI Corporation, Ohashi Takeru ,   IHI Corporation, Kitamura Shunya ,   IHI Corporation, Haruta Eisuke ,   KJTD Co. Ltd., Fukui Ryo
Published: May 2024

Infrared pulse thermography (PT) is a noncontact and convenient nondestructive inspection method, and its
application to various objects has been reported in many papers. However, conventional PT is not suitable for
detecting deep- or near-rear-surface defects. This study focuses on PT inspections of CFRP plates and
improvements in their defect detection capabilities. To improve the capability of detecting near-rear-surface
defects, a method for enhancing the heat transfer coefficient (HTC) of the rear surface during PT inspection was
examined in this study; this would increase the temperature difference in the defective areas observed in thermal
images. To investigate the effectiveness of the proposed method, experiments were conducted on CFRP specimens
with artificial defects. The CFRP specimens were inspected using the PT method, during which water was brought
into contact with the rear surfaces of the specimens to enhance the HTC. The experimental results showed that the
capability of detecting near-rear-surface defects improved when the rear surfaces were in contact with water with
forced convection. In addition, obtaining phase images by applying a Fourier transform to the experimentally
obtained temperature data (that is, pulse phase thermography: PPT) was examined. Consequently, the combination
of the enhancement of the rear-surface HTC and the use of phase images was significantly effective in improving
the defect detection capability.
Air-coupled ultrasonic inspection of resin materials using single-probe vertical reflection method
Authors:   University of Tokushima, Yano Taku ,   University of Tokushima, Ishikawa Masashi ,   University of Tokushima, Nishino Hideo
Published: May 2024

Air-coupled ultrasonic inspection is a noncontact and convenient nondestructive testing method. However, its
vertical reflection method using a single probe (i.e., pulse-echo mode) is known to be difficult to achieve, even
though it is frequently used inspection mode in conventional contact or water immersion ultrasonic testing. This
is because the reflectivity of ultrasonic waves at the boundary between air and the surface of inspection object is
enormous, and faint signals received after transmitting into the object are difficult to detect. In this study, in order
to achieve the air-coupled ultrasonic single-probe reflection method, transmitting chirp signals (waves with a
linearly frequency modulation) with an appropriate window function and applying a pulse compression technique
(a cross-correlation process between the received signal and a reference chirp signal) was examined, and its
effectiveness was investigated through experiments for polystyrene specimens. Experimental results showed that
the proposed method was effective in detecting faint reflection signals after propagating through the specimens,
and that the difference in plate thickness could be detected by observing the change of the signal-receiving period
of multiple reflection signals between the top and bottom surfaces of the specimens. These results demonstrate the
feasibility of nondestructive testing using the air-coupled ultrasonic vertical reflection method and could show an
important step toward its future practical applications.