Non-destructive Material Research Articles

Spatial and Temporal Visualization of Polymorphic Transformations in Pharmaceutical Tablets.

X-ray Diffraction Computed Tomography (XRD-CT) represents a cutting-edge method for non-destructive material analysis, offering the unique capability of providing molecular-level information with spatial resolution. In this study, we have applied XRD-CT to investigate pharmaceutically relevant tablets that have been subjected to a range of compression pressures typical in tablet manufacturing. By employing XRD-CT to pharmaceutical tablets, we reveal material changes without tablet destruction, thereby avoiding potential phase transformations during sample preparation that could lead to errors in the interpretation of the processes that have occurred. Utilizing a pressure-sensitive marker, glycolide, we have tracked changes within tablet structures induced by compression, pinpointing locations where glycolide undergoes pressure-induced transformation. Additionally, we conducted a follow-up study with analysis one month later, observing an in-situ hydrolysis reaction of glycolide within the tablets. Through the complementary use of electron diffraction, we have elucidated the structure of the hydrolysis product, further enhancing our understanding of temporal changes in the tablets.

Design, fabrication, and characterization of 1–3 piezoelectric composite air-coupled ultrasonic transducers with micro-membrane filter matching layer

Air-coupled ultrasonic transducers are widely used in various fields of nondestructive material characterization. This paper presents the fabrication and performance characterization of 1–3 piezoelectric composite air-coupled ultrasonic transducers operating at frequencies ranging from 400 kHz to 600 kHz. The transducers are fabricated using a dice-and-fill method with PZT-5 as the active material. A double-layer matching strategy is employed, utilizing hollow glass microsphere filled epoxy resin as the first matching and bonding layer. Additionally, micro-membrane filters with different pore sizes are used as the second matching layer. Thermoplastic adhesive TPU is utilized to bind the micro-membrane filter and the first matching layer. Due to the low acoustic impedance of the hollow glass microsphere filled epoxy resin and micro-membrane filter, acoustic impedance mismatch is reduced. Finite element simulation is used to determine the optimal ceramic volume fraction and ceramic pillar height of the 1–3 piezoelectric composites. When the pore size of the micro-membrane filter is 0.8 μm, the transducer achieves the lowest two-way insertion loss of −56.86 dB and the highest −6 dB bandwidth of 15.6 %, making it feasible for through mode applications.

Demonstration of shape analysis of neutron resonance transmission spectrum measured with a laser-driven neutron source

Laser-driven neutron sources (LDNSs) can generate strong short-pulse neutron beams, which are valuable for scientific studies and engineering applications. Neutron resonance transmission analysis (NRTA) is a nondestructive technique used for determining the areal density of each nuclide in a material sample using pulsed thermal and epithermal neutrons. Herein, we report the first successful NRTA performed using an LDNS driven by the Laser for Fast Ignition Experiment at the Institute of Laser Engineering, Osaka University. The key challenge was achieving a well-resolved resonance transmission spectrum for material analysis using an LDNS with a limited number of laser shots in the presence of strong background noise. We addressed this by employing a time-gated 6Li\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{6}{\ extrm{Li}}$$\\end{document}-glass scintillation neutron detector to measure the transmission spectra, reducing the impact of electromagnetic noise and neutron and gamma-ray flashes. Output waveforms were recorded for each laser shot and analyzed offline using a counting method. This approach yielded a spectrum with distinct resonances, which were attributed to 115In\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{115}\\,{\ extrm{In}}$$\\end{document} and 109Ag\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{109}{\ extrm{Ag}}$$\\end{document}, as confirmed through neutron transmission simulation. The spectrum was analyzed using the least-square nuclear-resonance fitting program, REFIT, demonstrating the possibility of using an LDNS for nondestructive areal-density material characterization.

Golay coded thermal wave imaging for inclusions inspection in titanium alloy (Ti-6Al-4V): an analytical study

Detecting and characterizing inclusions in metallic materials is crucial in nondestructive testing (NDT) and imaging to ensure structural integrity and reliability. In the field of nondestructive material assessment, infrared thermographic imaging is a well-established technology. This approach analyzes the thermal profile collected over a test specimen to find surface and sub-surface abnormalities. Infrared thermography has demonstrated rising interest in coded thermal excitation techniques and the accompanying data processing technologies in recent years. However, using coded excitations in thermal NDT is still uncommon. This research investigates the viability of using complementary Golay-coded excitation in active thermography. This unique method displays its usefulness in improving the detection sensitivity and resolution by efficiently minimizing the side lobes of the compressed pulse. The current analytical study demonstrates the flaw detection capability of Golay-coded thermal wave imaging (GCTWI) for analyzing titanium alloy materials with anomalies such as inclusions. The research replicates thermal wave propagation and interaction with various inclusion geometries and sizes at the same depths. Furthermore, a comparison study is done between GCTWI analytical and simulation models to validate these models. The correlation coefficient is used as a figure of merit to assess GCTWI’s ability to identify and precisely localize these inclusions. The results show that GCTWI has better fault detectability and spatial resolution capabilities, making it a viable approach for inclusion inspection. Overall, this study advances NDT and imaging approaches by proving the capability of GCTWI for the reliable and efficient identification of inclusions in Titanium Alloy (Ti-6Al-4V). The study’s findings can help to develop more effective inspection procedures for assuring and maintaining the structural integrity of Ti-6Al-4V components in various sectors, including aerospace, automotive, and biomedical engineering.

Two-dimensional Hilbert-Huang transform-based thermographic data processing for non-destructive material defect detection

ABSTRACT Previous research has established the Hilbert-Huang transform (HHT) as a powerful tool for processing and analysing one-dimensional time series signals. Its extension into multi-dimensional Euclidean spaces further demonstrates its versatility. In this study, we leverage a two-dimensional (2D) HHT to enhance non-destructive testing, utilising active infrared thermographic data to improve the detection of material defects. The proposed methodology incorporates a 2D HHT, which synergises multidimensional ensemble empirical mode decomposition with the Riesz transform (RT). This combination is adept at uncovering both global (i.e. intrinsic mode functions) and local (i.e. phase angle and spatial frequency) information. In particular, RT is integrated with a Gaussian filter, which allows for a more thorough analysis of the inherent characteristics of defects through the monogenic signal produced by RT. The experimental application of this method on a mosaic sample, intentionally embedded with defects, has yielded promising results. The approach effectively distinguishes critical defect signals from the surroundings, leading to more accurate and clearer results.

Nondestructive material characterization and component identification in sheet metal processing with electromagnetic methods

Electromagnetic methods for non-destructive evaluation (NDE) are presented, with which sheet metal components can be identified and their material properties can be characterized. The latter is possible with 3MA, the Micromagnetic Multiparametric Microstructure and stress Analyser. This is a combination of several micromagnetic NDE methods that make it possible to analyse the microstructure in a ferromagnetic material and to determine quantitative values of the mechanical material properties or the stress state. In the case of cold forming, the 3MA application for pre-process testing of sheet metal is discussed. Based on the 3MA information, the formability of the sheets can be predicted. To apply 3MA in-line, the influence of the relative speed and the relative distance between the 3MA probe head and the sheet was investigated. In a second study, a spatially resolved eddy current (EC) method was used to create an image of the intrinsic material microstructure of a component for its identification and traceability. It turned out, that these intrinsic fingerprint images can still be recognized even after subsequent plastic deformation or coating of the surface. This enabled the development of a marker-free traceability method for sheet metal processing. It is based on a low-cost array sensor and a specimen identification using robust and partly redundant features of the fingerprint images processed by machine learning (ML).

Development of long-range conductivity mechanisms in glass-like carbon

The conductivity mechanisms in glass-like carbon synthesised from SU-8 3005 photoresist are explored as a function of pyrolysis temperature (between 700–750 °C) utilising microwave dielectric spectroscopy techniques. Broadband measurements using an open-ended coaxial probe (BCP) are used to investigate the complex permittivity and conductivity as a function of frequency and show the development of long range conduction and sp2 carbon chain formation. Fixed frequency resonance measurements using microwave cavity perturbation (MCP) methods are shown as a way of measuring this transition and change in Q-factor without requiring contacts and therefore acting as a effective method for non-destructive and non-invasive measurements. Using these methods we show a clear change in the AC conductivity of glass-like carbon at a pyrolysis temperature of ∼730 °C and demonstrate how microwave cavity perturbation (MCP) can be used as a non-contact method of dielectric spectroscopy for determining the transition of conductivity mechanisms in glass-like carbon from short to long range and therefore as a method for non-destructive material quality control. We demonstrate that both BCP and MCP dielectric spectroscopy methods are effective at clearly detecting changes in the structure and conductivity mechanisms of glass-like carbon over a small pyrolysis temperature range.

Solution of nonlinear Lamb waves in plates with discontinuous thickness.

Nonlinear Lamb waves can propagate over long distances in plate and shell structures and are sensitive to the early fatigue damage of materials. Therefore, they offer unique advantages in the fields of nondestructive testing and material health monitoring. Plate and shell structures with discontinuous thicknesses (e.g., ribs, stiffeners, or joints) will cause nonlinear Lamb wave scattering, and it is necessary to study the scattering processes of nonlinear Lamb waves at discontinuities and how these processes impact the resulting signal characteristics. Thus, nonlinear Lamb waves can be used to identify the structural characteristics and defect characteristics of signals in practical applications. In this paper, the propagating and scattering processes of the second harmonic of a Lamb wave in a discontinuous plate are studied, including the contributions of the evanescent Lamb modes near the discontinuity and the nonlinear boundary effect at the discontinuity. The scattering characteristics of the second harmonics with respect to the frequency and geometry of the plate are analyzed. In addition, the integral formula is adjusted to improve the computational stability under different numbers of Lamb wave modes. Transient finite element simulation is used to validate the proposed method.

Automated non-destructive 3D printing filament material properties monitoring based on electric permittivity, longitudinal encoding and diameter multi-axes real-time measurements

Rapid prototyping is an essential part of today’s research and development process. The ability to produce objects quickly, cost-effectively and on-site is critical to meeting this fundamental requirement. One of the factors that leads to inconsistencies and defects in the produced parts is the uncompensated change in material properties used in the material extrusion 3D printing manufacturing process. This creates the need for a real-time, low-cost filament quality monitor that can characterize the material properties of the filament along its length. This can be achieved by tracking the variation in measured capacitive tube capacitance and diameter of different sensor types over multiple selected axes and encoding the results to a specific fragment of filament used in material extrusion 3D printing. With such collected data it is possible to monitor factors such as material moisture, roundness, internal and external defects, component proportions, relative electrical permeability, Poisson’s ratio and material type. This work presents the first proof of concept of such a device and describes its operating principle in detail. As examples of applications, filament material type recognition is presented based on the characteristics of several types of filaments from different manufacturers, the process of moisture absorption over time for selected filaments is described, and the detection of defects of varying degrees is shown.

Resonant ultrasound spectroscopy experimental design and optimization

Resonant Ultrasound Spectroscopy (RUS) is a nondestructive material characterization technique that utilizes solid body resonances to estimate elastic moduli. This method is advantageous over traditional mechanical testing due to the significantly lower number of required samples to estimate the same number of moduli. The goal of this project is to develop a high-throughput RUS system capable of measuring experimental resonances and mode shapes in a fraction of the time of traditional RUS measurements. A new system was designed which leverages data/image analysis algorithms to aid in sample alignment and data collection. A standardized sample geometry was also analyzed by performing a geometric sensitivity study and optimizing the aspect ratio of lengths of a parallelepiped. The results show that the optimized sample geometry is consistent between materials with varying elastic properties. In order to validate the design of the new RUS system a comparative study to an existing system was conducted. The results show that the newly designed system produces comparable resonant frequency and mode shape measurements.

Towards better copies of guitars: Compensate material variability with geometry

Luthiers have been trying to copy the sound of iconic instruments like Torres guitars for many years. Though precise geometric copies were manufactured, audible differences were found which can be attributed largely to the natural variability of wood. We were able to present a methodology allowing non-destructive material identification based on which a shape optimization was performed to compensate material variablility with specific geometric variations, allowing a much more exact copy of a guitar soundboard in terms of eigenfrequencies. We will present a generalization of this methodology to full guitars including almost arbitrary geometric adaptions and consideration of mode shapes in the optimization. A mesh morphing strategy allows to simultaneously define very general geometric adaptions and comparing mode shapes without re-meshing. Further, a parameterized reduced order numerical model will be presented in which all possible global geometric variations are mapped to the individual elements of the underlying finite-element model in symbolical form. This symbolical representation is then carried over to the assembled finite-element matrices resulting in an extremely efficient reduced model keeping the symbolic relationships. This is the absolute core requirement of an efficient shape optimization. The approach will be presented for hexahedral elements.

Maximizing visible Raman resolution of nanodiamond grains fabricated by coaxial arc plasma deposition through oxygen plasma etching optimization

Among the nondestructive carbon material characterization tools, the prominence of visible Raman spectroscopy has surged remarkably for many years due to its ability to explore a diverse array of carbon bonding configurations. However, to fully unlock the distinctive features concealed within carbon composite materials, additional specimen treatments or precise spectroscope calibrations are necessary. In the same regard, the tiny diamond grain size (5–10 nm) and the pronounced amount of sp2 carbon in the ultrananocrystalline diamond film represent major challenges in visible light excitation. In this work, we employ calibrated oxygen plasma reactive ion etching conditions to manifest the nanodiamond visible Raman signature from ultrananocrystalline diamond/amorphous carbon composite (UNCD/a‐C) films fabricated by coaxial arc plasma deposition. Upon plasma etching, the broad defect band in the visible Raman spectra converged toward the diamond characteristic Raman peak at 1332 cm−1. A detailed explanation of band components of the Raman spectra is extracted through peak fitting procedures. The results of Raman spectroscopy are further correlated with the electrical characteristics of the nitrogen‐doped UNCD/a‐C films due to the optimized oxygen plasma etching processes.

Comparatively Study of Non-Destructive test with different methods in various curing days

In non-destructive testing, materials, components, or assemblies are inspected, tested, or evaluated without being destroyed. In nondestructive testing, materials, components, and assemblies are evaluated for quality and integrity without damaging them. The use of non-destructive testing (NDT) is a popular method for assessing the strength and durability of existing concrete structures. An ultrasound pulse velocity test and a rebound hammer test are included in the NDT test. An NDT test includes both ultrasound pulse velocity testing and rebound hammer testing. Strength tests are conducted with rebound hammers, while quality tests are conducted with ultrasonic pulse velocity tests. A lab-made concrete cube was tested on three different ages-seven, fourteen, and 28 days-without destroying it. There were 15 cubes that were treated using non-destructive methods. Using both Schmidt rebound hammer and ultrasonic pulse velocity tests, we determined which non-destructive testing method was faster. In addition to surfaces, Schmidt rebound hammers are the toughest tools to use. Rebound number and concrete strength seem to be connected. Schmidt hammers were employed in both vertical and horizontal settings. Concrete’s ultrasonic pulse velocity is mostly determined by its identity and modulus of elasticity, that are motivated by the substances used in making the concrete in addition to its placement, compaction, and curing techniques.

Comparative Study of Destructive Method and Non-destructive with Ultra-Sonic Pulse Velocity Method

The appropriate percentages of cement, fine aggregates, coarse aggregates, and water are utilized to make concrete. Due to its relatively low price and widespread availability, it is a ubiquitous building material. Concrete in its fresh state can also be molded into any desired shape and size. Strength and durability are two of concrete’s most important characteristics (particularly when used for structural purposes). Verify the concrete’s compressive strength before placing it under the expected loads. NDT methods, both destructive and non-destructive, can be used to assess the compressive strength of hardened concrete. A non- destructive test does not harm the concrete specimen, whereas a destructive test (DT) crushes the cast specimen until it breaks. In non-destructive testing, materials, components or assemblies are inspected, tested or evaluated without destroying their serviceability. This study compares the compressive strength of concrete utilising an ultrasonic pulse velocity approach, which is both destructive and non-destructive. Concrete cubes measuring 150 mm by 150 mm by 150 mm were created using the concrete mix grades 25N/mm2 and 30N/mm2, and they were allowed to cure for 28 days. There were 12 cubes produced and used for the study. The determine compressive strength between destructive and non -destructive (ultra-sonic pulse velocity) test method.

Non-Destructive Material Analysis of Whetstones Discovered in Grain Transport Ship of the Early Joseon Period

Non-Destructive Material Analysis of Whetstones Discovered in Grain Transport Ship of the Early Joseon Period

Mutual interactions between bulk waves and guided waves in a quadratic nonlinear elastic medium

The high sensitivity of nonlinear ultrasonic waves to the early stages of local material deteriorations makes them ideal candidates for nondestructive material characterization. Guided elastic waves, which can be emitted and received on the same surface, expand the possibilities to inspect inaccessible domains to test and monitor existing structures. The pure measurement of the amplitude of the second harmonic has only limited significance, since it is difficult to distinguish between the rather weak material nonlinearity and the nonlinearities from the technical equipment. This can be avoided by mixing two ultrasonic waves of different frequencies, which results in superposed harmonics at these frequencies. In this study, the mutual interactions between bulk waves and guided waves in a quadratic nonlinear elastic medium are investigated by highly efficient computations. In addition, numerical examples for the wave interaction in a finite area with nonlinearity in an otherwise linearly elastic host medium are presented and discussed to explore the effects of individual parameters as well as possible experimental implementation.

A Study on the Preservation Treatment of Gold-Leafed Clothing Artefacts Excavated from a Tomb of the Cheongsong Shim Clan - Focusing on Bugeum Wonsam and Jikgeum Chima (Skirt) -

The purpose of this study is to perform a non-destructive material analysis and conservation treatments on two gold-leafed clothing artefacts (Bugeum Wonsam and Jikgeum Chima (Skirt)) excavated from a tomb of the Cheongsong Shim Clan held by the Chungbuk National University Museum. The artefacts, which were excavated in April 2003, had been stored in storage and were found to be wrinkled, contaminated, hardened and dried. The preservation treatment of the artefacts was performed by means of material analysis and repair. The analysis of the material using scanning electron microscopy SEM, FT-IR, colorimetric and XRF analyses showed that the material is silk fiber, and the analysis of the gold leaf layer using XRF showed that the gold leaf is gold (Au). The preservation treatment was performed by investigating the condition of the artefacts and conducting preliminary experiments on the reinforcing agents. For the reinforcement treatment, a 10% reinforcing agent of cow glue was applied to protect the gold leaf layer to prevent flaking of the gold leaf layer during wet cleaning, and a 2% reinforcing agent was applied after repair . For wet cleaning, a natural cleaning liquid mixed with cypress extract was used at a concentration of 1.0%. For wet cleaning, a natural cleaning solution mixed with Oriental arborvitae extract was used at a concentration of 1.0%. After cleaning, the artefacts were reinforced and repaired to restore their original shapes, completing the preservation treatment including packaging and storage.

Bonding wire characterization using non-destructive X-ray imaging

Counterfeiting in the semiconductor industry poses a significant threat to the economy and can lead to lower performance and reliability of electronic devices. X-ray technology in this respect is commonly used for non-destructive testing to identify physical defects and anomalies in integrated circuits. However, for accurate material identification, destructive methods such as spectroscopic techniques including X-ray diffraction and X-ray fluorescence are typically required. In this work, a fast and non-destructive method is presented for material characterization of bonding wires in ICs and other SMD components by measuring X-ray absorption profiles. The results demonstrated that the X-ray imaging technique can effectively distinguish between bonding wires made of gold, silver, copper, and aluminum. Moreover, the thickness of these materials can also be detected. This technique exhibits high potential for utilization as a simple and quick method for non-destructive material characterization in the industrial environment.

Application of ultrafast laser beam shaping in micro-optical elements

The manufacturing and application of micro-optical elements are constantly evolving toward miniaturization, integration, and intelligence and have important applications in holographic displays, optical imaging, laser processing, information processing, and other fields. Ultrafast lasers, with their ultrashort pulse width, extremely high peak power, high processing resolution, small thermal influence zone, and nondestructive material processing advantages, have become an important processing method for preparing micro-optical elements. However, the laser output from the laser usually has a Gaussian distribution, with limitations in spatial and temporal energy and shape distribution, making it difficult to meet the requirements of processing efficiency and quality, which poses new challenges to ultrafast laser manufacturing technology. Therefore, by shaping the ultrafast laser beam and regulating nonlinear optical effects, the optimization and adjustment of the beam shape can be achieved, thus improving the quality and efficiency of micro-optical element processing. Ultrafast laser beam shaping technology provides a new method for the manufacture of micro-optical elements. This article first introduces the commonly used manufacturing methods for micro-optical elements. Second, from the perspective of the temporal domain, spatial domain, and spatiotemporal domain, the basic principles, methods, and existing problems of ultrafast laser beam shaping are summarized. Then, the application of these shaping technologies in the preparation of micro-optical elements is elaborated. Finally, the challenges and future development prospects of ultrafast laser beam shaping technology are discussed.

Cyber Physical Production Systems for Deep Drawing

Abstract Deep Drawing is an essential manufacturing technology for car body parts. High process stability is a key to reducing scrap and therefore the ecological footprint during production. To deal with an unknown fluctuation of the incoming material properties and uncertainties considering the friction, an adaptive process needs to be implemented. Various approaches have been pursued in the past, but not all of them are suited for industrial series production with high demands for equipment durability, cost efficiency, and flexibility. For this reason, a new concept for cyber-physical production systems (CPPS) in deep drawing is presented, linking the data from the simulation, tool, press, material, and finished part quality. Two common application scenarios are distinguished. First, these are large outer parts with a complex geometry and high value, typically produced with tandem presses. Second, smaller structural parts from high-strength steel for the body in white (BIW) are usually produced through a transfer or progressive die. Non-destructive material testing, supplier material certificates, and data measured directly in the forming tool are considered regarding the input. The servo curve and blank holder force (BHF) operate as control instances. Within the two application scenarios, a reactive and a preventive solution are characterized. As a first step toward the implementation of the CPPS, material inflow, and force sensors are installed and tested in an industrially relevant deep drawing tool.