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Non-destructive Testing of Materials and Parts: Techniques, Case Studies and Practical Applications

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Advanced Materials Characterization".

Deadline for manuscript submissions: 10 August 2024 | Viewed by 3047

Special Issue Editors


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Guest Editor
Department of Mechanical Engineering, Instituto Superior de Engenharia do Porto, Porto, Portugal
Interests: composites; machining; damage onset and propagation; damage assessment; image processing; non-destructive testing; mechanical testing
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
Department of Industrial Production Engineering, Instituto Superior de entre Douro e Vouga, Santa Maria da Feira, Portugal
Interests: biodegradable composites; green composites; mechanical characterization; production technologies; damage assessment; non-destructive techniques
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Non-destructive testing (NDT) is the application of scientific principles of physics, chemistry, and mathematics for the development of adequate procedures and specific equipment that can be used to study a part, object, or complex structure, like a car, airplane, or railway bridge, without causing any harm to the object under examination.

NDT is also used in many other industries, as well as in other non-industrial applications; for example, NDT is used to make sure that parts do not have defects that would make the customer unhappy or that passengers and luggage in an airport comply with the strict safety regulations. Some of the equipment and procedures used in NDT can also be found in the medical field, like with the use of X-rays in dental work or ultrasound in echography.

Presently, there is no doubt about the importance of NDT, as it leads to a considerable amount of savings by not destroying parts, some of them expensive, as it replaces the still too present destructive testing technique. Nowadays, there are many NDT techniques available. The field of quality control works to perfect these technologies year after year, allowing us to effectively replace destructive testing.

This Special Issue intends to act as a forum for the presentation of the latest developments in the field of research and development, as well as the demonstration of practical cases of the application of NDT in all industrial areas that can help foster future developments on this interesting theme. The most recent breakthroughs in the development of equipment and instruments by the NDT machine manufacturers will play an important role, allowing the NDT community to be in contact with some cutting-edge techniques and enabling new possibilities for their usage in new areas.

As Editors of this Special Issue, it is our pleasure to invite you to submit a manuscript, whether in the form of research articles or review articles. All submissions will be peer reviewed, and a first decision will be provided to authors approximately 14 days after submission. Once accepted, papers will be published continuously in the journal and listed together on the Special Issue webpage.

It is our pleasure to invite you to submit a manuscript for this Special Issue. Full papers, communications, and reviews are all welcome.

Prof. Dr. Luís Miguel Pereira Durão
Prof. Dr. Nuno Calçada Loureiro
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • NDT techniques
  • image processing
  • damage assessment
  • damage modelling
  • reliability
  • safety
  • mechanical strength
  • standardization

Published Papers (5 papers)

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Research

14 pages, 6637 KiB  
Article
Monitoring Fatigue Damage of Orthotropic Steel Decks Using Nonlinear Ultrasonic Waves
by Jiahe Liu, Fangtong Zheng, Wei Shen and Dongsheng Li
Materials 2024, 17(12), 2792; https://doi.org/10.3390/ma17122792 - 7 Jun 2024
Viewed by 269
Abstract
Orthotropic steel decks (OSDs) are commonly used in the construction of bridges due to their load-bearing capabilities. However, they are prone to fatigue damage over time due to the cyclic loads from vehicles. Therefore, the early structural health monitoring of fatigue damage in [...] Read more.
Orthotropic steel decks (OSDs) are commonly used in the construction of bridges due to their load-bearing capabilities. However, they are prone to fatigue damage over time due to the cyclic loads from vehicles. Therefore, the early structural health monitoring of fatigue damage in OSDs is crucial for ensuring bridge safety. Moreover, Lamb waves, as elastic waves propagating in OSD plate-like structures, are characterized by their long propagation distances and minimal attenuation. This paper introduces a method of emitting high-energy ultrasonic waves onto the OSD surface to capture the nonlinear Lamb waves formed, thereby calculating the nonlinear parameters. These parameters are then correlated with the fatigue damage endured, forming a damage index (DI) for monitoring the fatigue life of OSDs. Experimental results indicate that as fatigue damage increases, the nonlinear parameters exhibit a significant initial increase followed by a decrease. The behavior is distinct from the characteristic parameters of linear ultrasound (velocity and energy), which also exhibit changes but to a relatively smaller extent. The proposed DI and fatigue life based on nonlinear parameters can be fitted with a Gaussian curve, with the R-squared value of the fitting curve being close to 1. Additionally, this paper discusses the influence of rib welds within the OSDs on the DI, whereby as fatigue damage increases, it enlarges the value of the nonlinear parameters without altering their trend. The proposed method provides a more effective approach for monitoring early fatigue damage in OSDs. Full article
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26 pages, 5683 KiB  
Article
Effects of Seawater on Mechanical Performance of Composite Sandwich Structures: A Machine Learning Framework
by Norman Osa-uwagboe, Amadi Gabriel Udu, Vadim V. Silberschmidt, Konstantinos P. Baxevanakis and Emrah Demirci
Materials 2024, 17(11), 2549; https://doi.org/10.3390/ma17112549 - 25 May 2024
Viewed by 308
Abstract
Sandwich structures made with fibre-reinforced plastics are commonly used in maritime vessels thanks to their high strength-to-weight ratios, corrosion resistance, and buoyancy. Understanding their mechanical performance after moisture uptake and the implications of moisture uptake for their structural integrity and safety within out-of-plane [...] Read more.
Sandwich structures made with fibre-reinforced plastics are commonly used in maritime vessels thanks to their high strength-to-weight ratios, corrosion resistance, and buoyancy. Understanding their mechanical performance after moisture uptake and the implications of moisture uptake for their structural integrity and safety within out-of-plane loading regimes is vital for material optimisation. The use of modern methods such as acoustic emission (AE) and machine learning (ML) could provide effective techniques for the assessment of mechanical behaviour and structural health monitoring. In this study, the AE features obtained from quasi-static indentation tests on sandwich structures made from E-glass fibre face sheets with polyvinyl chloride foam cores were employed. Time- and frequency-domain features were then used to capture the relevant information and patterns within the AE data. A k-means++ algorithm was utilized for clustering analysis, providing insights into the principal damage modes of the studied structures. Three ensemble learning algorithms were employed to develop a damage-prediction model for samples exposed and unexposed to seawater and were loaded with indenters of different geometries. The developed models effectively identified all damage modes for the various indenter geometries under different loading conditions with accuracy scores between 86.4 and 95.9%. This illustrates the significant potential of ML for the prediction of damage evolution in composite structures for marine applications. Full article
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11 pages, 5228 KiB  
Article
High-Resolution Ultrasound to Quantify Sub-Surface Wrinkles in a Woven CFRP Laminate
by Md Admay Amif and David A. Jack
Materials 2024, 17(9), 2002; https://doi.org/10.3390/ma17092002 - 25 Apr 2024
Cited by 1 | Viewed by 582
Abstract
Carbon fiber reinforced polymer (CFRP) composites are popular materials in the aerospace and automotive industries because of their low weight, high strength, and corrosion resistance. However, wrinkles or geometric distortions in the composite layers significantly reduce their mechanical performance and structural integrity. This [...] Read more.
Carbon fiber reinforced polymer (CFRP) composites are popular materials in the aerospace and automotive industries because of their low weight, high strength, and corrosion resistance. However, wrinkles or geometric distortions in the composite layers significantly reduce their mechanical performance and structural integrity. This paper presents a method for non-destructively extracting the three-dimensional geometry, lamina by lamina, of a laminated composite. A method is introduced for fabricating consistent out-of-plane wrinkled CFRP laminate panels, simulating the in-service wrinkle observed in industries that utilize thick structure composites such as the vertical lift or wind power industries. The individual lamina geometries are extracted from the fabricated coupon with an embedded wrinkle from captured ultrasonic waveforms generated from single-element conventional ultrasonic (UT) scan data. From the extracted waveforms, a method is presented to characterize the wrinkle features within each individual lamina, specifically the spatially varying wrinkle height and intensity for the wrinkle. Parts were fabricated with visibly undetectable wrinkles using a wet layup process and a hot press for curing. Scans were performed in a conventional immersion tank scanning system, and the scan data were analyzed for wrinkle detection and characterization. Extraction of the layers was performed based on tracking the voltage peaks from A-scans in the time domain. Spatial Gaussian averaging was performed to smooth the A-scans, from which the surfaces were extracted for each individual lamina. The extracted winkle surface aligned with the anticipated wrinkle geometry, and a single parameter for quantification of the wrinkle intensity for each lamina is presented. Full article
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23 pages, 5428 KiB  
Article
Generation of Mechanical Characteristics in Workpiece Subsurface Layers through Milling
by Michael Storchak, Larysa Hlembotska and Oleksandr Melnyk
Materials 2024, 17(7), 1552; https://doi.org/10.3390/ma17071552 - 28 Mar 2024
Viewed by 481
Abstract
The generation of mechanical characteristics in workpiece subsurface layers as a result of the cutting process has a predominant influence on the performance properties of machined parts. The effect of the end milling process on the mechanical characteristics of the machined subsurface layers [...] Read more.
The generation of mechanical characteristics in workpiece subsurface layers as a result of the cutting process has a predominant influence on the performance properties of machined parts. The effect of the end milling process on the mechanical characteristics of the machined subsurface layers was evaluated using nondestructive methods: instrumented nanoindentation and sclerometry (scratching). In this paper, the influence of one of the common processes of materials processing by cutting—the process of end tool milling—on the generation of mechanical characteristics of workpiece machined subsurface layers is studied. The effect of the end milling process on the character of mechanical property formation was evaluated through the coincidence of the cutting process energy characteristics with the mechanical characteristics of the machined subsurface layers. The total cutting power and cutting work in the tertiary cutting zone area were used as energy characteristics of the end milling process. The modes of the end milling process are considered as the main parameters affecting these energy characteristics. The mechanical characteristics of the workpiece machined subsurface layers were the microhardness of the subsurface layers and the total work of indenter penetration, determined by instrumental nanoindentation, and the maximum depth of indenter penetration, determined by sclerometry. Titanium alloy Ti10V2Fe3Al (Ti-1023) was used as the machining material. Based on the evaluation of the coincidence of the cutting process energy characteristics with the specified mechanical characteristics of the machined subsurface layers, the milling mode effect of the studied titanium alloy, in particular the cutter feed and cutting speed, on the generated mechanical characteristics was established. Full article
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22 pages, 6900 KiB  
Article
Damage Detection in FRP-Reinforced Concrete Elements
by Pranit Malla, Seyed Saman Khedmatgozar Dolati, Jesus D. Ortiz, Armin B. Mehrabi, Antonio Nanni and Jiayi Ding
Materials 2024, 17(5), 1171; https://doi.org/10.3390/ma17051171 - 2 Mar 2024
Cited by 1 | Viewed by 942
Abstract
Fiber-Reinforced Polymer (FRP) composites have emerged as a promising alternative to conventional steel reinforcements in concrete structures owing to their benefits of corrosion resistance, higher strength-to-weight ratio, reduced maintenance cost, extended service life, and superior durability. However, there has been limited research on [...] Read more.
Fiber-Reinforced Polymer (FRP) composites have emerged as a promising alternative to conventional steel reinforcements in concrete structures owing to their benefits of corrosion resistance, higher strength-to-weight ratio, reduced maintenance cost, extended service life, and superior durability. However, there has been limited research on non-destructive testing (NDT) methods applicable for identifying damage in FRP-reinforced concrete (FRP-RC) elements. This knowledge gap has often limited its application in the construction industry. Engineers and owners often lack confidence in utilizing this relatively new construction material due to the challenge of assessing its condition. Thus, the main objective of this study is to determine the applicability of two of the most common NDT methods: the Ground-Penetrating Radar (GPR) and Phased Array Ultrasonic (PAU) methods for the detection of damage in FRP-RC elements. Three slab specimens with variations in FRP type (glass-, carbon- and basalt-FRP, i.e., GFRP, CFRP, and BFRP, respectively), bar diameter, bar depths, and defect types were investigated to determine the limitations and detection capabilities of these two NDT methods. The results show that GPR could detect damage in GFRP bars and CFRP strands, but PAU was limited to damage detection in CFRP strands. The findings of this study show the applicability of conventional NDT methods to FRP-RC and at the same time identify the areas with a need for further research. Full article
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