Table of Contents 23 Articles in Issue: 2016-05-01 | |
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Low Velocity Elastomer Polymer Wedges Applied to TOFD E. Ginzel1 98 , R. Ginzel2 22, R. MacNeil2 4 1Materials Research Institute 101, Waterloo, Canada 2Innovation Polymers 6, Kitchener, Ontario, Canada TOFD, polymers, velocity, ultrasonic
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Time of Flight Diffraction (TOFD) relies on a beam with relatively high divergence to provide suitable volume coverage. Refracting wedges provide a means of directing the beam towards the inspected volume. Most wedges are made of common polymers with acoustic velocities between about 2400m/s and 2800m/s which are 40-47% the average compression velocity in steel. This provides useful positive refraction in steels with relatively small probe centre spacing (PCS). However, when testing lower velocity materials and where access from the weld centreline is limited, it can be useful to have wedges that have lower velocities. Some applications can use water encased in a reservoir, but preventing the water from leaking and avoiding air bubbles can be problematic. A viable alternative is to fabricate the wedge from a low attenuation low velocity polymer. Examples of the quality of signals obtained using low velocity polymer are given in this paper
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| Acoustic Velocity Determination for AUT on Spiral Pipe Girth Welds E. Ginzel1 98 , H. Van Dijk2 3 1Materials Research Institute 101, Waterloo, Canada 2JES Pipelines, Willemstad, Canada Ultrasonic Testing (UT)
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Determining acoustic velocity is a critical aspect for the correct calculation of Snell’s Law to determine refracted angle and to position the location of flaws along the soundpath of an ultrasonic beam. This has been seen as a critical part of preparations in girth weld inspections using zonal discrimination where it is mandated by codes. The typical steels used in pipeline construction are slightly anisotropic, making it necessary to determine the shear velocities at different angles in the plane of inspection. Anisotropy occurs due to the alignment of the acicular crystals in the direction of rolling. When the pipe is made with a longitudinal seam the velocities change in a relatively simple fashion because the changes occur in predominantly one plane of the crystal axes. However, when the pipe is made by the spiral welding process, the girth weld inspection requires the beam to cross the plane of the crystal axes at an angle. Refraction calculations for the longitudinal seam pipe have been demonstrated to use the fast SH shear mode. However, for pipe made using the spiral welding process, it has been found that the fast SH shear mode need not provide the best velocity for calculating the refracted angle in a zonal discrimination technique.
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| Development of NDT Based Electronic System for measurement of ultrasonic Parameter of Coal Sample D. Kate , N. Choudhari 2, A. Choudhari Department of Electronics and Communication; Bhagwati College of Engineering 2, Nagpur, India Ultrasonic, Coal, NDT, Velocity, attenuation
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Coal is a complex resource and usually it varies within the same deposit. As far as applications are concerned the properties of coal are required to be checked. Acceptable and well-known methods are ingrained and these are widely used in laboratories worldwide. Amongst the techniques used the most commonly use technique is non-destructive technique (NDT) for detecting component and flaw characterization. Other than the flaw characteristics, parameter which is equally important to assess the structural integrity of engineering components is the material property. Researchers all over the world are working on extensive study to characterize, both microstructural and mechanical properties of materials by ultrasonic testing. This paper highlights the ultrasonic testing parameters useful for material characterization studies. In this paper we have presented our electronic system that has been developed for the measurement of velocity and attenuation of ultrasonic signal through coal sample which helps in characterization of coal.
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| An Overview Algorithm to Minimise Side Lobes for 2D Circular Phased Array S. Mondal School of Engineering; London South Bank University 6, London, United Kingdom Phased array, ultrasonic beam focusing and total focusing method
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The report presents an algorithm called the total focusing method for the circular phased array. It shows an improvement in the focusing for the main lobe beam and eliminates the effects of the side lobe. The report visualizes the effects for different ring sizes of the circular array and the effect of different numbers of array elements. The results of this modelling indicate that, for a given number of elements, placing them around the circular ring allow them to perform best and that the element spacing should be less than half a wavelength to avoid grating lobes and to eliminate grating lobes. In addition to that it describes how the TFM images have been built by computing half time traces of the transmitter and receiver array.
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| Impact-Echo Technique to Assess Concrete Structures R. Otero1 9 , G. Sulbarán2 2, E. Moreno3 7 1Centro de Tecnología de Materiales; Fundación Instituto de Ingeniería 3, Caracas, Venezuela 2Ingenieros Asesores en Metalurgia y Soldadura, , Mexico 3Technological Centre; Fundacion Tecnalia R&I 5, Minano, Spain Ultrasonic Testing (UT)
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This paper presents a methodology and a prototype developed in our NDT group, for the application of nondestructive Impact-Echo technique, which has been implemented and introduced in Venezuela. This technique has shown excellent results to evaluate and characterize different types of concrete structures with experiences in other countries, well-documented and accessible. It is worth noting that this technique can be applied to a wide range of viscoelastic materials and the emphasis in this paper is made in the inspection of concrete structures as an alternative methodology to existing destructive methods. The study is based on the fact that concrete is one of the most used materials in infrastructure construction and therefore the results would be of immediate use. In addition to the possibility of thickness measurement, the technique can detect and evaluate a wide range of "defects" in the concrete structures, such as cracks open to the surface, the presence of laminations, cavities, etc. Any imaging application of this technique would help to determine the internal state in a wide range of basic structures such as floors, beams, slabs, walls, columns, tunnels, etc.
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| The Ultrasonic Polar Scan for Composite Characterization and Damage Assessment: Past, Present and Future M. Kersemans1 7, A. Martens2 2, J. Degrieck1 8, K. Van den Abeel2 8, S. Delrue2 7, L. Pyl3 6, F. Zastavnik3 4, H. Sol3 5, W. Van Paepegem1 7 1Department of Materials Science and Engineering; University of Ghent (UGent) 51, Ghent, Belgium 2aDepartment of Materials Science and Engineering bWave Propagation and Signal Processing Group; Katholieke Universiteit Leuven Campus Kulak (KULK) 13, Kortrijk, Belgium 3Department Mechanics of Materials and Constuctions; Vrije Universiteit Brussel (VUB) 54, Brussel, Belgium ultrasound, ultrasonic polar scan, composites, NDT, characterization, damage
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In the early 1980’s, the ultrasonic polar scan (UPS) technique was developed to assess the fiber direction of composites in a nondestructive way. In spite of the recognition by several researchers as being a sophisticated and promising methodology for nondestructive testing (NDT) and materials science, little advance was made during the following 30 years. Recently however, the UPS technique experienced a strong revival and various modifications to the original UPS setup have been successfully implemented. This revival has exposed several powerful capabilities and interesting applications of the UPS technique for material characterization and damage assessment. This paper gives a short historical overview of the UPS technique for characterizing and inspecting (damaged) fiber-reinforced plastics. In addition, a few future research lines are given, which will further expand the applicability and potential of the UPS method to a broader range of (damaged) materials, bringing the UPS technique to the next level of maturity.
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| Lamb Wave Interaction with Adhesively Bonded Stiffeners and Disbonds Using 3D Vibrometry R. Marks1 , A. Clarke1 2, C. Featherston1 6, C. Paget2 2, R. Pullin1 19 1School of Engineering; Cardiff University 25, Cardiff, United Kingdom 2Airbus Operations 4, Bristol, United Kingdom lamb waves, vibrometry, adhesive bonding, ultrasonics, non-destructive testing, structural health monitoring
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There are many advantages to adhesively bonding stiffeners onto aircraft structures rather
than using traditional mechanical fastening methods. However there is a lack of confidence of the
structural integrity of adhesively bonded joints over time. Acousto-ultrasonic Lamb waves have
shown great potential in structural health monitoring applications in both metallic and composite
structures. This paper presents an experimental investigation of the use of acousto-ultrasonic Lamb
waves for the monitoring of adhesively bonded joints in metallic structures using 3D scanning laser
vibrometry. Two stiffened panels were manufactured, one with an intentional disbonded region.
Lamb wave interaction with the healthy and disbonded stiffeners was investigated at three excitation
frequencies. A windowed root-mean-squared technique was applied to quantify where Lamb wave
energy was reflected, attenuated and transmitted across the structure enabling the size and shape of
the defect to be visualised which was verified by traditional ultrasonic inspection techniques.
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| Acquisition of Complete Acoustic Emission Amplitude Records during Rock Fracture Experiments S. Goodfellow1, J. Flynn2, J. Reyes-montes2, M. Nasseri1, R. Young1 2 1Department of Civil Engineering; University of Toronto 41, Toronto, Canada 2Applied Seismology Consultants, Shrewsbury, United Kingdom
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This paper presents the results from a triaxial deformation experiment where acoustic emission
(AE) waveforms were continuously recorded at two different gain levels. The purpose of
this work is to quantify the extent of missing amplitude data, which is typically lost at critical
points during rock fracture experiments due to waveform clipping. A cylindrical sample of
Westerly granite was axially loaded until failure at a constant displacement rate and 25 MPa of
confining pressure. AE was monitored by 18 piezoelectric sensors mounted on the cylinder ends
and around its circumference. AE data was continuously acquired and digitized at 10 MHz and
12-bits for the duration of the experiment where four channels were amplified 6 dB and the rest
40 dB. Two large stress-drops occurred in the post peak-stress regime resulting in large amplitude
bursts of AE. Channels amplified 40 dB showed complete amplitude saturation, making
event analysis difficult whereas those channels amplified 6 dB remained unclipped. We conclude
that the amount of missing amplitude data is significant for experiments of this nature and should
be considered when designing AE acquisition setups.
| Journal-AE Session: Volume 32, 2014 | Quantitative Evaluation of Rejuvenators to Restore Embrittlement Temperatures in Oxidized Asphalt Mixtures using Acoustic Emission Z. Sun, N. Farace, B. Behnia 2, W. Buttlar 3, H. Reis 4 aDepartment of Industrial and Enterprise Systems Engineering bDepartment of Civil and Environmental Engineering; University of Illinois 14, Urbana, IL,, USA Asphalt concrete, oven-aging, embrittlement temperatures, asphalt binder, rejuvenator
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Towards developing a method capable to assess the efficiency of rejuvenators to restore embrittlement
temperatures of oxidized asphalt binders towards their original, i.e., unaged values,
three gyratory compacted specimens were manufactured with mixtures oven-aged for 36 hours at
135oC. In addition, one gyratory compacted specimen manufactured using a short-term ovenaged
mixture for two hours at 155oC was used for control to simulate aging during plant production.
Each of these four gyratory compacted specimens was then cut into two cylindrical specimen
5 cm thick for a total of six 36-hour oven-aged specimens and two short-term aging specimens.
Two specimens aged for 36 hours and the two short-term specimens were tested using an
acoustic emission approach to obtain base acoustic emission response of short-term and severelyaged
specimens. The remaining four specimens oven-aged for 36 hours were then treated by
spreading their top surface with rejuvenator in the amount of 10% of the binder by weight. These
four specimens were then tested using the same acoustic emission approach after two, four,
six, and eight weeks of dwell time. It was observed that the embrittlement temperatures of the
short-term aged and severely oven-aged specimens were -25oC and -15oC, respectively. It was
also observed that after four weeks of dwell time, the rejuvenator-treated samples had recuperated
the original embrittlement temperatures. In addition, it was also observed that the rejuvenator
kept acting upon the binder after four weeks of dwell time; at eight weeks of dwell time, the
specimens had an embrittlement temperature about one grade cooler than the embrittlement temperature
corresponding to the short-term aged specimen.
| Journal-AE Session: Volume 32, 2014 | Diagnostics of Degradative Changes in Paramagnetic Alloys with the use of Low Frequency Impedance Spectroscopy Z. Żurek1 9, M. Witoś2 17 1Silesian University of Technology 9, Katowice, Poland 2Air Force Institute of Technology 37, Warsaw, Poland
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In the article theoretical bases of the low frequency impedance spectroscopy method and
possibilities of its use in the diagnostics of paramagnetic alloys used in aeronautics are
explained. The main focus is put on description of interaction of electromagnetic radiation
with the material, eddy currents excited in the material (carrier of diagnostic data),
modelling of the material and a given diagnostic problem with an equivalent RLC circuit,
method of exciting and observation of eddy currents and bases of qualitative and
quantitative analysis of the test signal. The knowledge necessary to consciously use eddy
currents in NDT and SHM tests directed on the identification of an early phase of material
degradation (the phase preceding an open crack) is also of particular importance in the
article. The applied measurement instrumentation and sample results of in-house and other
research centres’ tests are presented. The in-house tests were performed on objects made of
the ASTM 289 class C austenitic steel and ALSi13Mg1CuNi aluminium alloy and on
paramagnetic materials used in transport and power industry, whose values of magnetic
susceptibility are similar, but their composition, microstructure and other mechanisms of
the early phase of fatigue degradation are different. Taking them as an example, the need of
taking into consideration the specificity of aeronautical materials and diagnostic problem
being solved by the selection of the frequency of electromagnetic radiation, methodology
applied in preparation of test methods and diagnostic criteria is highlighted.
| AeroNDT 2015 Session: Emerging Technology in Electromagnetism | IT Support of NDE and SHM with Application of the Metal Magnetic Memory Method M. Witoś 17, M. Zieja 4, B. Kurzyk 2 Air Force Institute of Technology 37, Warsaw, Poland
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The paper has been intended to introduce a complex research problem, that is present in aviation, power engineering, mining and transport, with regard to assurance of operational safety for ageing technology, which is exposed to different form of material degradation. Theoretical reasons of active control of material fatigue and selection of reliable state observer have been outlined. The Metal Magnetic Memory Method (MMM) and the scope of scientific research, that are conducted in polish scientific centers in order to confirm and extend its operational possibilities to diagnose early stages of progressive material degradation, have also been presented. Taking the MMM Method into account, IT support of non-destructive testing has been considered with particular interest in the necessity of objective quality assessment and reliability of non-destructive testing performed by external companies (outsourcing). The presented topic has been illustrated by means of practical examples regarding problems in aviation, power engineering, mining and transport.
| AeroNDT 2015 Session: IT Developments and Solutions | Expert System to Support Operational Safety of the TS-11“Iskra” Aircraft and Overhauls of the SO-3 Engines M. Witoś 17, M. Wachłaczenko 5 Air Force Institute of Technology 37, Warsaw, Poland
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The paper has been intended to introduce the Tip Timing Method (TTM) to monitor rotating blades in an aircraft compressor, that was implemented in Poland: in maintenance of the TS-11 “Iskra” aircraft in 1993 and in the SO-3 engine overhaul technology in 1997. The scope of research performed before the implementation of TTM and its advisory expert-software have been outlined. On the base of conducted experimental research, it has been confirmed that computer-based system to support operational safety of the TS-11 “Iskra” aircraft and overhauls of engines SO-3 has enabled to actively control a process of material fatigue. As a result of reason identification of fatigue problems, flight safety of the TS-11 “Iskra” aircraft was improved and the following problems were eliminated from operational use: a fatigue problem with I stage rotor blades in compressors and instable operation of the SO-3 engines. Unconscious human errors were also eliminated and technical culture of maintenance and overhauls of the SO-3 engines was improved. Reasons for other technical problems with the SO-3 engines were reliably determined. Presented topic has been illustrated by means of many practical examples.
| AeroNDT 2015 Session: Structural Health Monitoring in General | Internal Stress Monitoring of In-Service Structural Steel Members with Ultrasonic Method Z. Li1 4, J. He1 4, J. Teng1 5, Y. Wang2 4 1School of Civil and Environment Engineering, Shenzhen Graduate School; Harbin Institute of Technology (HIT) 38, Harbin, China 2Department of Civil and Environmental Engineering; University of Surrey 10, Surrey, United Kingdom Ultrasonic Testing (UT), acoustoelasticity, Internal stresses, longitudinal critically refracted waves
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Internal stress in structural steel members is an important parameter for steel structures
in their design, construction, and service stages. However, it is hard to measure via traditional
approaches. Among the existing non-destructive testing (NDT) methods, the ultrasonic method has
received the most research attention. Longitudinal critically refracted (Lcr) waves, which propagate
parallel to the surface of the material within an effective depth, have shown great potential as an
effective stress measurement approach. This paper presents a systematic non-destructive evaluation
method to determine the internal stress in in-service structural steel members using Lcr waves. Based
on theory of acoustoelasticity, a stress evaluation formula is derived. Factor of stress to acoustic
time difference is used to describe the relationship between stress and measurable acoustic results.
A testing facility is developed and used to demonstrate the performance of the proposed method.
Two steel members are measured by using the proposed method and the traditional strain gauge
method for verification. Parametric studies are performed on three steel members and the aluminum
plate to investigate the factors that influence the testing results. The results show that the proposed
method is effective and accurate for determining stress in in-service structural steel members.
| NDT Review Session: Materials (MDPI) | High Temperature Shear Horizontal Electromagnetic Acoustic Transducer for GuidedWave Inspection M. Kogia , T. Gan 30, W. Balachandran 6, M. Livadas 3, V. Kappatos 10, I. Szabo , A. Mohimi 3, A. Round Brunel Innovation Centre ((BIC); Brunel University 36, Uxbridge, United Kingdom Electromagnetic Acoustic Transducers, EMAT, Guided Wave Testing, high temperature inspection
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Guided Wave Testing (GWT) using novel Electromagnetic Acoustic Transducers (EMATs)
is proposed for the inspection of large structures operating at high temperatures. To date, high
temperature EMATs have been developed only for thickness measurements and they are not suitable
for GWT. A pair of water-cooled EMATs capable of exciting and receiving Shear Horizontal (SH0)
waves for GWT with optimal high temperature properties (up to 500 C) has been developed. Thermal
and Computational Fluid Dynamic (CFD) simulations of the EMAT design have been performed
and experimentally validated. The optimal thermal EMAT design, material selection and operating
conditions were calculated. The EMAT was successfully tested regarding its thermal and GWT
performance from ambient temperature to 500 C.
| NDT Review Session: Sensors (MDPI) | A Practical and Portable Solids-State Electronic Terahertz Imaging System K. Smart1, J. Du1, L. Li1 , D. Wang1 , K. Leslie1, F. Ji2 , D. Zeng2 , X. Li2 1Commonwealth Scientific and Industrial Research Organisation (CSIRO) 2, Lindfield, Australia 2Chengdu Shuguang Optical Fiber Network Co., Ltd, Chengdu, China terahertz, imaging, solid-state electronic components
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A practical compact solid-state terahertz imaging system is presented. Various beam
guiding architectures were explored and hardware performance assessed to improve its compactness,
robustness, multi-functionality and simplicity of operation. The system performance in terms of
image resolution, signal-to-noise ratio, the electronic signal modulation versus optical chopper, is
evaluated and discussed. The system can be conveniently switched between transmission and
reflection mode according to the application. A range of imaging application scenarios was explored
and images of high visual quality were obtained in both transmission and reflection mode.
| NDT Review Session: Sensors (MDPI) | Dynamic Measurement for the Diameter of A Train Wheel Based on Structured-Light Vision Z. Gong , J. Sun , G. Zhang Key Laboratory of Precision Opto-Mechatronics Technology, Ministry of Education; Beihang University (BUAA) 39, Beijing, China train wheel diameter, dynamic measurement, structured-light vision, machine vision
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Wheels are very important for the safety of a train. The diameter of the wheel is a significant
parameter that needs regular inspection. Traditional methods only use the contact points of the
wheel tread to fit the rolling round. However, the wheel tread is easily influenced by peeling or
scraping. Meanwhile, the circle fitting algorithm is sensitive to noise when only three points are used.
This paper proposes a dynamic measurement method based on structured-light vision. The axle of
the wheelset and the tread are both employed. The center of the rolling round is determined by the
axle rather than the tread only. Then, the diameter is calculated using the center and the contact
points together. Simulations are performed to help design the layout of the sensors, and the influences
of different noise sources are also analyzed. Static and field experiments are both performed, and the
results show it to be quite stable and accurate.
| NDT Review Session: Sensors (MDPI) | Reducing Sweeping Frequencies in Microwave NDT Employing Machine Learning Feature Selection A. Moomen1 , A. Ali2 2, O. Ramahi2 2 1Department of Computer Science; Rochester Institute of Technology, Rochester, USA 2Electrical and Computer Engineering (ECE); University of Waterloo 18, Waterloo, Canada microwave sensors, nondestructive testing, feature selection, machine learning
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Nondestructive Testing (NDT) assessment of materials’ health condition is useful for
classifying healthy from unhealthy structures or detecting flaws in metallic or dielectric structures.
Performing structural health testing for coated/uncoated metallic or dielectric materials with the
same testing equipment requires a testing method that can work on metallics and dielectrics such
as microwave testing. Reducing complexity and expenses associated with current diagnostic
practices of microwave NDT of structural health requires an effective and intelligent approach
based on feature selection and classification techniques of machine learning. Current microwave
NDT methods in general based on measuring variation in the S-matrix over the entire operating
frequency ranges of the sensors. For instance, assessing the health of metallic structures using a
microwave sensor depends on the reflection or/and transmission coefficient measurements as a
function of the sweeping frequencies of the operating band. The aim of this work is reducing sweeping
frequencies using machine learning feature selection techniques. By treating sweeping frequencies
as features, the number of top important features can be identified, then only the most influential
features (frequencies) are considered when building the microwave NDT equipment. The proposed
method of reducing sweeping frequencies was validated experimentally using a waveguide sensor
and a metallic plate with different cracks. Among the investigated feature selection techniques
are information gain, gain ratio, relief, chi-squared. The effectiveness of the selected features
were validated through performance evaluations of various classification models; namely, Nearest
Neighbor, Neural Networks, Random Forest, and Support Vector Machine. Results showed good
crack classification accuracy rates after employing feature selection algorithms.
| NDT Review Session: Sensors (MDPI) | Concrete Condition Assessment Using Impact-Echo Method and Extreme Learning Machines J. Zhang1 , Y. Weizhong2 , D. Cui1 1Anhui and Huaihe River Institute of Hydraulic Research, Bengbo, 2GE Global Research 4, Niskayuna, NY, USA defect detection, extreme learning machine, feature extraction, machine learning, nondestructive testing, wavelet transform
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The impact-echo (IE) method is a popular non-destructive testing (NDT) technique widely
used for measuring the thickness of plate-like structures and for detecting certain defects inside
concrete elements or structures. However, the IE method is not effective for full condition assessment
(i.e., defect detection, defect diagnosis, defect sizing and location), because the simple frequency
spectrum analysis involved in the existing IE method is not sufficient to capture the IE signal patterns
associated with different conditions. In this paper, we attempt to enhance the IE technique and enable
it for full condition assessment of concrete elements by introducing advanced machine learning
techniques for performing comprehensive analysis and pattern recognition of IE signals. Specifically,
we use wavelet decomposition for extracting signatures or features out of the raw IE signals and
apply extreme learning machine, one of the recently developed machine learning techniques, as
classification models for full condition assessment. To validate the capabilities of the proposed
method, we build a number of specimens with various types, sizes, and locations of defects and
perform IE testing on these specimens in a lab environment. Based on analysis of the collected IE
signals using the proposed machine learning based IE method, we demonstrate that the proposed
method is effective in performing full condition assessment of concrete elements or structures.
| NDT Review Session: Sensors (MDPI) | Evaluation of SHM System Produced by Additive Manufacturing via Acoustic Emission and Other NDT Methods M. Strantza 5, D. Aggelis 27, D. De Baere 6, P. Guillaume 11, D. Van Hemelrijck 18 aDepartment of Mechanics of Materials and Constructions b2Department of Mechanical Engineering and Aeronautics cDepartment of Mechanical Engineering cDepartment Mechanics of Materials & Constructions (MeMC; Vrije Universiteit Brussel (VUB) 54, Brussel, Belgium acoustic emission, additive manufacturing, structural health monitoring, liquid penetrant inspection, radiography, eddy current
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During the last decades, structural health monitoring (SHM) systems are used in order to detect damage in structures. We have developed a novel structural health monitoring approach, the so-called “effective structural health monitoring” (eSHM) system. The current SHM system is incorporated into a metallic structure by means of additive manufacturing (AM) and has the possibility to advance life safety and reduce direct operative costs. It operates based on a network of capillaries that are integrated into an AM structure. The internal pressure of the capillaries is continuously monitored by a pressure sensor. When a crack nucleates and reaches the capillary, the internal pressure changes signifying the existence of the flaw. The main objective of this paper is to evaluate the crack detection capacity of the eSHM system and crack location accuracy by means of various non-destructive testing (NDT) techniques. During this study, detailed acoustic emission (AE) analysis was applied in AM materials for the first time in order to investigate if phenomena like the Kaiser effect and waveform parameters used in conventional metals can offer valuable insight into the damage accumulation of the AM structure as well. Liquid penetrant inspection, eddy current and radiography were also used
OPEN ACCESS
Sensors 2015, 15 26710
in order to confirm the fatigue damage and indicate the damage location on un-notched four-point bending AM metallic specimens with an integrated eSHM system. It is shown that the eSHM system in combination with NDT can provide correct information on the damage condition of additive manufactured metals.
| NDT Review Session: Sensors (MDPI) | A Micro-Computed Tomography Technique to Study the Quality of Fibre Optics Embedded in Composite Materials G. Chiesura1, G. Luyckx1 5, E. Voet1 2, N. Lammens1 3, W. Van Paepegem1 7, J. Degrieck1 8, M. Dierick1 4, L. Van hoorebeke1 6, P. Vanderniepen1 , S. Sulejmani2 4, C. Sonnenfeld2 3, T. Geernaert2 6, F. Berghmans2 6 1aDepartment of Materials Science and Engineering bDept. Physics and Astronomy; University of Ghent (UGent) 51, Ghent, Belgium 2Brussels Photonics Team (B-PHOT); Vrije Universiteit Brussel (VUB) 54, Brussel, Belgium carbon fibre, defects, radiography, autoclave, prepreg
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Quality of embedment of optical fibre sensors in carbon fibre-reinforced
polymers plays an important role in the resultant properties of the composite, as well as
for the correct monitoring of the structure. Therefore, availability of a tool able to check
the optical fibre sensor-composite interaction becomes essential. High-resolution 3D X-ray
Micro-Computed Tomography, or Micro-CT, is a relatively new non-destructive inspection
technique which enables investigations of the internal structure of a sample without
actually compromising its integrity. In this work the feasibility of inspecting the position,
the orientation and, more generally, the quality of the embedment of an optical fibre sensor
in a carbon fibre reinforced laminate at unit cell level have been proven.
| NDT Review Session: Sensors (MDPI) |
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